Code

Merge branch 'db/checkout'
authorJunio C Hamano <gitster@pobox.com>
Wed, 27 Feb 2008 20:53:26 +0000 (12:53 -0800)
committerJunio C Hamano <gitster@pobox.com>
Wed, 27 Feb 2008 20:53:26 +0000 (12:53 -0800)
* db/checkout: (21 commits)
  checkout: error out when index is unmerged even with -m
  checkout: show progress when checkout takes long time while switching branches
  Add merge-subtree back
  checkout: updates to tracking report
  builtin-checkout.c: Remove unused prefix arguments in switch_branches path
  checkout: work from a subdirectory
  checkout: tone down the "forked status" diagnostic messages
  Clean up reporting differences on branch switch
  builtin-checkout.c: fix possible usage segfault
  checkout: notice when the switched branch is behind or forked
  Build in checkout
  Move code to clean up after a branch change to branch.c
  Library function to check for unmerged index entries
  Use diff -u instead of diff in t7201
  Move create_branch into a library file
  Build-in merge-recursive
  Add "skip_unmerged" option to unpack_trees.
  Discard "deleted" cache entries after using them to update the working tree
  Send unpack-trees debugging output to stderr
  Add flag to make unpack_trees() not print errors.
  ...

Conflicts:

Makefile

12 files changed:
1  2 
Makefile
builtin-branch.c
builtin-commit.c
builtin-merge-recursive.c
builtin-read-tree.c
builtin.h
cache.h
contrib/examples/git-checkout.sh
git.c
read-cache.c
t/t7201-co.sh
unpack-trees.c

diff --cc Makefile
index 8d9f11e75e8fb1095761fd7fd25e66b1d73e6fa2,40fa41b5f3a914cfb82366158e8e27bac3bb8938..a5b6eebf1a0b65b481f6dd8f1e38006b46e87c83
+++ b/Makefile
@@@ -327,8 -318,7 +327,8 @@@ LIB_OBJS = 
        alloc.o merge-file.o path-list.o help.o unpack-trees.o $(DIFF_OBJS) \
        color.o wt-status.o archive-zip.o archive-tar.o shallow.o utf8.o \
        convert.o attr.o decorate.o progress.o mailmap.o symlinks.o remote.o \
-       transport.o bundle.o walker.o parse-options.o ws.o archive.o \
 -      transport.o bundle.o walker.o parse-options.o ws.o archive.o branch.o
++      transport.o bundle.o walker.o parse-options.o ws.o archive.o branch.o \
 +      alias.o
  
  BUILTIN_OBJS = \
        builtin-add.o \
Simple merge
Simple merge
index 0000000000000000000000000000000000000000,558a58e4d3aaff6e66f25220b30ea9749b50be08..6fe4102c0cfb29031f7fdce68ca4d1937e2fefd7
mode 000000,100644..100644
--- /dev/null
@@@ -1,0 -1,1751 +1,1754 @@@
 -              if (value)
 -                      default_ll_merge = strdup(value);
+ /*
+  * Recursive Merge algorithm stolen from git-merge-recursive.py by
+  * Fredrik Kuivinen.
+  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
+  */
+ #include "cache.h"
+ #include "cache-tree.h"
+ #include "commit.h"
+ #include "blob.h"
+ #include "builtin.h"
+ #include "tree-walk.h"
+ #include "diff.h"
+ #include "diffcore.h"
+ #include "run-command.h"
+ #include "tag.h"
+ #include "unpack-trees.h"
+ #include "path-list.h"
+ #include "xdiff-interface.h"
+ #include "interpolate.h"
+ #include "attr.h"
+ #include "merge-recursive.h"
+ static int subtree_merge;
+ static struct tree *shift_tree_object(struct tree *one, struct tree *two)
+ {
+       unsigned char shifted[20];
+       /*
+        * NEEDSWORK: this limits the recursion depth to hardcoded
+        * value '2' to avoid excessive overhead.
+        */
+       shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
+       if (!hashcmp(two->object.sha1, shifted))
+               return two;
+       return lookup_tree(shifted);
+ }
+ /*
+  * A virtual commit has
+  * - (const char *)commit->util set to the name, and
+  * - *(int *)commit->object.sha1 set to the virtual id.
+  */
+ static unsigned commit_list_count(const struct commit_list *l)
+ {
+       unsigned c = 0;
+       for (; l; l = l->next )
+               c++;
+       return c;
+ }
+ static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
+ {
+       struct commit *commit = xcalloc(1, sizeof(struct commit));
+       static unsigned virtual_id = 1;
+       commit->tree = tree;
+       commit->util = (void*)comment;
+       *(int*)commit->object.sha1 = virtual_id++;
+       /* avoid warnings */
+       commit->object.parsed = 1;
+       return commit;
+ }
+ /*
+  * Since we use get_tree_entry(), which does not put the read object into
+  * the object pool, we cannot rely on a == b.
+  */
+ static int sha_eq(const unsigned char *a, const unsigned char *b)
+ {
+       if (!a && !b)
+               return 2;
+       return a && b && hashcmp(a, b) == 0;
+ }
+ /*
+  * Since we want to write the index eventually, we cannot reuse the index
+  * for these (temporary) data.
+  */
+ struct stage_data
+ {
+       struct
+       {
+               unsigned mode;
+               unsigned char sha[20];
+       } stages[4];
+       unsigned processed:1;
+ };
+ static struct path_list current_file_set = {NULL, 0, 0, 1};
+ static struct path_list current_directory_set = {NULL, 0, 0, 1};
+ static int call_depth = 0;
+ static int verbosity = 2;
+ static int rename_limit = -1;
+ static int buffer_output = 1;
+ static struct strbuf obuf = STRBUF_INIT;
+ static int show(int v)
+ {
+       return (!call_depth && verbosity >= v) || verbosity >= 5;
+ }
+ static void flush_output(void)
+ {
+       if (obuf.len) {
+               fputs(obuf.buf, stdout);
+               strbuf_reset(&obuf);
+       }
+ }
+ static void output(int v, const char *fmt, ...)
+ {
+       int len;
+       va_list ap;
+       if (!show(v))
+               return;
+       strbuf_grow(&obuf, call_depth * 2 + 2);
+       memset(obuf.buf + obuf.len, ' ', call_depth * 2);
+       strbuf_setlen(&obuf, obuf.len + call_depth * 2);
+       va_start(ap, fmt);
+       len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
+       va_end(ap);
+       if (len < 0)
+               len = 0;
+       if (len >= strbuf_avail(&obuf)) {
+               strbuf_grow(&obuf, len + 2);
+               va_start(ap, fmt);
+               len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
+               va_end(ap);
+               if (len >= strbuf_avail(&obuf)) {
+                       die("this should not happen, your snprintf is broken");
+               }
+       }
+       strbuf_setlen(&obuf, obuf.len + len);
+       strbuf_add(&obuf, "\n", 1);
+       if (!buffer_output)
+               flush_output();
+ }
+ static void output_commit_title(struct commit *commit)
+ {
+       int i;
+       flush_output();
+       for (i = call_depth; i--;)
+               fputs("  ", stdout);
+       if (commit->util)
+               printf("virtual %s\n", (char *)commit->util);
+       else {
+               printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
+               if (parse_commit(commit) != 0)
+                       printf("(bad commit)\n");
+               else {
+                       const char *s;
+                       int len;
+                       for (s = commit->buffer; *s; s++)
+                               if (*s == '\n' && s[1] == '\n') {
+                                       s += 2;
+                                       break;
+                               }
+                       for (len = 0; s[len] && '\n' != s[len]; len++)
+                               ; /* do nothing */
+                       printf("%.*s\n", len, s);
+               }
+       }
+ }
+ static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
+               const char *path, int stage, int refresh, int options)
+ {
+       struct cache_entry *ce;
+       ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
+       if (!ce)
+               return error("addinfo_cache failed for path '%s'", path);
+       return add_cache_entry(ce, options);
+ }
+ /*
+  * This is a global variable which is used in a number of places but
+  * only written to in the 'merge' function.
+  *
+  * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
+  *                       don't update the working directory.
+  *               0    => Leave unmerged entries in the cache and update
+  *                       the working directory.
+  */
+ static int index_only = 0;
+ static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
+ {
+       parse_tree(tree);
+       init_tree_desc(desc, tree->buffer, tree->size);
+ }
+ static int git_merge_trees(int index_only,
+                          struct tree *common,
+                          struct tree *head,
+                          struct tree *merge)
+ {
+       int rc;
+       struct tree_desc t[3];
+       struct unpack_trees_options opts;
+       memset(&opts, 0, sizeof(opts));
+       if (index_only)
+               opts.index_only = 1;
+       else
+               opts.update = 1;
+       opts.merge = 1;
+       opts.head_idx = 2;
+       opts.fn = threeway_merge;
+       init_tree_desc_from_tree(t+0, common);
+       init_tree_desc_from_tree(t+1, head);
+       init_tree_desc_from_tree(t+2, merge);
+       rc = unpack_trees(3, t, &opts);
+       cache_tree_free(&active_cache_tree);
+       return rc;
+ }
+ struct tree *write_tree_from_memory(void)
+ {
+       struct tree *result = NULL;
+       if (unmerged_cache()) {
+               int i;
+               output(0, "There are unmerged index entries:");
+               for (i = 0; i < active_nr; i++) {
+                       struct cache_entry *ce = active_cache[i];
+                       if (ce_stage(ce))
+                               output(0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
+               }
+               return NULL;
+       }
+       if (!active_cache_tree)
+               active_cache_tree = cache_tree();
+       if (!cache_tree_fully_valid(active_cache_tree) &&
+           cache_tree_update(active_cache_tree,
+                             active_cache, active_nr, 0, 0) < 0)
+               die("error building trees");
+       result = lookup_tree(active_cache_tree->sha1);
+       return result;
+ }
+ static int save_files_dirs(const unsigned char *sha1,
+               const char *base, int baselen, const char *path,
+               unsigned int mode, int stage)
+ {
+       int len = strlen(path);
+       char *newpath = xmalloc(baselen + len + 1);
+       memcpy(newpath, base, baselen);
+       memcpy(newpath + baselen, path, len);
+       newpath[baselen + len] = '\0';
+       if (S_ISDIR(mode))
+               path_list_insert(newpath, &current_directory_set);
+       else
+               path_list_insert(newpath, &current_file_set);
+       free(newpath);
+       return READ_TREE_RECURSIVE;
+ }
+ static int get_files_dirs(struct tree *tree)
+ {
+       int n;
+       if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
+               return 0;
+       n = current_file_set.nr + current_directory_set.nr;
+       return n;
+ }
+ /*
+  * Returns an index_entry instance which doesn't have to correspond to
+  * a real cache entry in Git's index.
+  */
+ static struct stage_data *insert_stage_data(const char *path,
+               struct tree *o, struct tree *a, struct tree *b,
+               struct path_list *entries)
+ {
+       struct path_list_item *item;
+       struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
+       get_tree_entry(o->object.sha1, path,
+                       e->stages[1].sha, &e->stages[1].mode);
+       get_tree_entry(a->object.sha1, path,
+                       e->stages[2].sha, &e->stages[2].mode);
+       get_tree_entry(b->object.sha1, path,
+                       e->stages[3].sha, &e->stages[3].mode);
+       item = path_list_insert(path, entries);
+       item->util = e;
+       return e;
+ }
+ /*
+  * Create a dictionary mapping file names to stage_data objects. The
+  * dictionary contains one entry for every path with a non-zero stage entry.
+  */
+ static struct path_list *get_unmerged(void)
+ {
+       struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
+       int i;
+       unmerged->strdup_paths = 1;
+       for (i = 0; i < active_nr; i++) {
+               struct path_list_item *item;
+               struct stage_data *e;
+               struct cache_entry *ce = active_cache[i];
+               if (!ce_stage(ce))
+                       continue;
+               item = path_list_lookup(ce->name, unmerged);
+               if (!item) {
+                       item = path_list_insert(ce->name, unmerged);
+                       item->util = xcalloc(1, sizeof(struct stage_data));
+               }
+               e = item->util;
+               e->stages[ce_stage(ce)].mode = ce->ce_mode;
+               hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
+       }
+       return unmerged;
+ }
+ struct rename
+ {
+       struct diff_filepair *pair;
+       struct stage_data *src_entry;
+       struct stage_data *dst_entry;
+       unsigned processed:1;
+ };
+ /*
+  * Get information of all renames which occurred between 'o_tree' and
+  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
+  * 'b_tree') to be able to associate the correct cache entries with
+  * the rename information. 'tree' is always equal to either a_tree or b_tree.
+  */
+ static struct path_list *get_renames(struct tree *tree,
+                                       struct tree *o_tree,
+                                       struct tree *a_tree,
+                                       struct tree *b_tree,
+                                       struct path_list *entries)
+ {
+       int i;
+       struct path_list *renames;
+       struct diff_options opts;
+       renames = xcalloc(1, sizeof(struct path_list));
+       diff_setup(&opts);
+       DIFF_OPT_SET(&opts, RECURSIVE);
+       opts.detect_rename = DIFF_DETECT_RENAME;
+       opts.rename_limit = rename_limit;
+       opts.output_format = DIFF_FORMAT_NO_OUTPUT;
+       if (diff_setup_done(&opts) < 0)
+               die("diff setup failed");
+       diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
+       diffcore_std(&opts);
+       for (i = 0; i < diff_queued_diff.nr; ++i) {
+               struct path_list_item *item;
+               struct rename *re;
+               struct diff_filepair *pair = diff_queued_diff.queue[i];
+               if (pair->status != 'R') {
+                       diff_free_filepair(pair);
+                       continue;
+               }
+               re = xmalloc(sizeof(*re));
+               re->processed = 0;
+               re->pair = pair;
+               item = path_list_lookup(re->pair->one->path, entries);
+               if (!item)
+                       re->src_entry = insert_stage_data(re->pair->one->path,
+                                       o_tree, a_tree, b_tree, entries);
+               else
+                       re->src_entry = item->util;
+               item = path_list_lookup(re->pair->two->path, entries);
+               if (!item)
+                       re->dst_entry = insert_stage_data(re->pair->two->path,
+                                       o_tree, a_tree, b_tree, entries);
+               else
+                       re->dst_entry = item->util;
+               item = path_list_insert(pair->one->path, renames);
+               item->util = re;
+       }
+       opts.output_format = DIFF_FORMAT_NO_OUTPUT;
+       diff_queued_diff.nr = 0;
+       diff_flush(&opts);
+       return renames;
+ }
+ static int update_stages(const char *path, struct diff_filespec *o,
+                        struct diff_filespec *a, struct diff_filespec *b,
+                        int clear)
+ {
+       int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
+       if (clear)
+               if (remove_file_from_cache(path))
+                       return -1;
+       if (o)
+               if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
+                       return -1;
+       if (a)
+               if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
+                       return -1;
+       if (b)
+               if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
+                       return -1;
+       return 0;
+ }
+ static int remove_path(const char *name)
+ {
+       int ret;
+       char *slash, *dirs;
+       ret = unlink(name);
+       if (ret)
+               return ret;
+       dirs = xstrdup(name);
+       while ((slash = strrchr(name, '/'))) {
+               *slash = '\0';
+               if (rmdir(name) != 0)
+                       break;
+       }
+       free(dirs);
+       return ret;
+ }
+ static int remove_file(int clean, const char *path, int no_wd)
+ {
+       int update_cache = index_only || clean;
+       int update_working_directory = !index_only && !no_wd;
+       if (update_cache) {
+               if (remove_file_from_cache(path))
+                       return -1;
+       }
+       if (update_working_directory) {
+               unlink(path);
+               if (errno != ENOENT || errno != EISDIR)
+                       return -1;
+               remove_path(path);
+       }
+       return 0;
+ }
+ static char *unique_path(const char *path, const char *branch)
+ {
+       char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
+       int suffix = 0;
+       struct stat st;
+       char *p = newpath + strlen(path);
+       strcpy(newpath, path);
+       *(p++) = '~';
+       strcpy(p, branch);
+       for (; *p; ++p)
+               if ('/' == *p)
+                       *p = '_';
+       while (path_list_has_path(&current_file_set, newpath) ||
+              path_list_has_path(&current_directory_set, newpath) ||
+              lstat(newpath, &st) == 0)
+               sprintf(p, "_%d", suffix++);
+       path_list_insert(newpath, &current_file_set);
+       return newpath;
+ }
+ static int mkdir_p(const char *path, unsigned long mode)
+ {
+       /* path points to cache entries, so xstrdup before messing with it */
+       char *buf = xstrdup(path);
+       int result = safe_create_leading_directories(buf);
+       free(buf);
+       return result;
+ }
+ static void flush_buffer(int fd, const char *buf, unsigned long size)
+ {
+       while (size > 0) {
+               long ret = write_in_full(fd, buf, size);
+               if (ret < 0) {
+                       /* Ignore epipe */
+                       if (errno == EPIPE)
+                               break;
+                       die("merge-recursive: %s", strerror(errno));
+               } else if (!ret) {
+                       die("merge-recursive: disk full?");
+               }
+               size -= ret;
+               buf += ret;
+       }
+ }
+ static int make_room_for_path(const char *path)
+ {
+       int status;
+       const char *msg = "failed to create path '%s'%s";
+       status = mkdir_p(path, 0777);
+       if (status) {
+               if (status == -3) {
+                       /* something else exists */
+                       error(msg, path, ": perhaps a D/F conflict?");
+                       return -1;
+               }
+               die(msg, path, "");
+       }
+       /* Successful unlink is good.. */
+       if (!unlink(path))
+               return 0;
+       /* .. and so is no existing file */
+       if (errno == ENOENT)
+               return 0;
+       /* .. but not some other error (who really cares what?) */
+       return error(msg, path, ": perhaps a D/F conflict?");
+ }
+ static void update_file_flags(const unsigned char *sha,
+                             unsigned mode,
+                             const char *path,
+                             int update_cache,
+                             int update_wd)
+ {
+       if (index_only)
+               update_wd = 0;
+       if (update_wd) {
+               enum object_type type;
+               void *buf;
+               unsigned long size;
+               if (S_ISGITLINK(mode))
+                       die("cannot read object %s '%s': It is a submodule!",
+                           sha1_to_hex(sha), path);
+               buf = read_sha1_file(sha, &type, &size);
+               if (!buf)
+                       die("cannot read object %s '%s'", sha1_to_hex(sha), path);
+               if (type != OBJ_BLOB)
+                       die("blob expected for %s '%s'", sha1_to_hex(sha), path);
+               if (make_room_for_path(path) < 0) {
+                       update_wd = 0;
+                       goto update_index;
+               }
+               if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
+                       int fd;
+                       if (mode & 0100)
+                               mode = 0777;
+                       else
+                               mode = 0666;
+                       fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
+                       if (fd < 0)
+                               die("failed to open %s: %s", path, strerror(errno));
+                       flush_buffer(fd, buf, size);
+                       close(fd);
+               } else if (S_ISLNK(mode)) {
+                       char *lnk = xmemdupz(buf, size);
+                       mkdir_p(path, 0777);
+                       unlink(path);
+                       symlink(lnk, path);
+                       free(lnk);
+               } else
+                       die("do not know what to do with %06o %s '%s'",
+                           mode, sha1_to_hex(sha), path);
+       }
+  update_index:
+       if (update_cache)
+               add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
+ }
+ static void update_file(int clean,
+                       const unsigned char *sha,
+                       unsigned mode,
+                       const char *path)
+ {
+       update_file_flags(sha, mode, path, index_only || clean, !index_only);
+ }
+ /* Low level file merging, update and removal */
+ struct merge_file_info
+ {
+       unsigned char sha[20];
+       unsigned mode;
+       unsigned clean:1,
+                merge:1;
+ };
+ static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
+ {
+       unsigned long size;
+       enum object_type type;
+       if (!hashcmp(sha1, null_sha1)) {
+               mm->ptr = xstrdup("");
+               mm->size = 0;
+               return;
+       }
+       mm->ptr = read_sha1_file(sha1, &type, &size);
+       if (!mm->ptr || type != OBJ_BLOB)
+               die("unable to read blob object %s", sha1_to_hex(sha1));
+       mm->size = size;
+ }
+ /*
+  * Customizable low-level merge drivers support.
+  */
+ struct ll_merge_driver;
+ typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
+                          const char *path,
+                          mmfile_t *orig,
+                          mmfile_t *src1, const char *name1,
+                          mmfile_t *src2, const char *name2,
+                          mmbuffer_t *result);
+ struct ll_merge_driver {
+       const char *name;
+       const char *description;
+       ll_merge_fn fn;
+       const char *recursive;
+       struct ll_merge_driver *next;
+       char *cmdline;
+ };
+ /*
+  * Built-in low-levels
+  */
+ static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
+                          const char *path_unused,
+                          mmfile_t *orig,
+                          mmfile_t *src1, const char *name1,
+                          mmfile_t *src2, const char *name2,
+                          mmbuffer_t *result)
+ {
+       /*
+        * The tentative merge result is "ours" for the final round,
+        * or common ancestor for an internal merge.  Still return
+        * "conflicted merge" status.
+        */
+       mmfile_t *stolen = index_only ? orig : src1;
+       result->ptr = stolen->ptr;
+       result->size = stolen->size;
+       stolen->ptr = NULL;
+       return 1;
+ }
+ static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
+                       const char *path_unused,
+                       mmfile_t *orig,
+                       mmfile_t *src1, const char *name1,
+                       mmfile_t *src2, const char *name2,
+                       mmbuffer_t *result)
+ {
+       xpparam_t xpp;
+       if (buffer_is_binary(orig->ptr, orig->size) ||
+           buffer_is_binary(src1->ptr, src1->size) ||
+           buffer_is_binary(src2->ptr, src2->size)) {
+               warning("Cannot merge binary files: %s vs. %s\n",
+                       name1, name2);
+               return ll_binary_merge(drv_unused, path_unused,
+                                      orig, src1, name1,
+                                      src2, name2,
+                                      result);
+       }
+       memset(&xpp, 0, sizeof(xpp));
+       return xdl_merge(orig,
+                        src1, name1,
+                        src2, name2,
+                        &xpp, XDL_MERGE_ZEALOUS,
+                        result);
+ }
+ static int ll_union_merge(const struct ll_merge_driver *drv_unused,
+                         const char *path_unused,
+                         mmfile_t *orig,
+                         mmfile_t *src1, const char *name1,
+                         mmfile_t *src2, const char *name2,
+                         mmbuffer_t *result)
+ {
+       char *src, *dst;
+       long size;
+       const int marker_size = 7;
+       int status = ll_xdl_merge(drv_unused, path_unused,
+                                 orig, src1, NULL, src2, NULL, result);
+       if (status <= 0)
+               return status;
+       size = result->size;
+       src = dst = result->ptr;
+       while (size) {
+               char ch;
+               if ((marker_size < size) &&
+                   (*src == '<' || *src == '=' || *src == '>')) {
+                       int i;
+                       ch = *src;
+                       for (i = 0; i < marker_size; i++)
+                               if (src[i] != ch)
+                                       goto not_a_marker;
+                       if (src[marker_size] != '\n')
+                               goto not_a_marker;
+                       src += marker_size + 1;
+                       size -= marker_size + 1;
+                       continue;
+               }
+       not_a_marker:
+               do {
+                       ch = *src++;
+                       *dst++ = ch;
+                       size--;
+               } while (ch != '\n' && size);
+       }
+       result->size = dst - result->ptr;
+       return 0;
+ }
+ #define LL_BINARY_MERGE 0
+ #define LL_TEXT_MERGE 1
+ #define LL_UNION_MERGE 2
+ static struct ll_merge_driver ll_merge_drv[] = {
+       { "binary", "built-in binary merge", ll_binary_merge },
+       { "text", "built-in 3-way text merge", ll_xdl_merge },
+       { "union", "built-in union merge", ll_union_merge },
+ };
+ static void create_temp(mmfile_t *src, char *path)
+ {
+       int fd;
+       strcpy(path, ".merge_file_XXXXXX");
+       fd = xmkstemp(path);
+       if (write_in_full(fd, src->ptr, src->size) != src->size)
+               die("unable to write temp-file");
+       close(fd);
+ }
+ /*
+  * User defined low-level merge driver support.
+  */
+ static int ll_ext_merge(const struct ll_merge_driver *fn,
+                       const char *path,
+                       mmfile_t *orig,
+                       mmfile_t *src1, const char *name1,
+                       mmfile_t *src2, const char *name2,
+                       mmbuffer_t *result)
+ {
+       char temp[3][50];
+       char cmdbuf[2048];
+       struct interp table[] = {
+               { "%O" },
+               { "%A" },
+               { "%B" },
+       };
+       struct child_process child;
+       const char *args[20];
+       int status, fd, i;
+       struct stat st;
+       if (fn->cmdline == NULL)
+               die("custom merge driver %s lacks command line.", fn->name);
+       result->ptr = NULL;
+       result->size = 0;
+       create_temp(orig, temp[0]);
+       create_temp(src1, temp[1]);
+       create_temp(src2, temp[2]);
+       interp_set_entry(table, 0, temp[0]);
+       interp_set_entry(table, 1, temp[1]);
+       interp_set_entry(table, 2, temp[2]);
+       output(1, "merging %s using %s", path,
+              fn->description ? fn->description : fn->name);
+       interpolate(cmdbuf, sizeof(cmdbuf), fn->cmdline, table, 3);
+       memset(&child, 0, sizeof(child));
+       child.argv = args;
+       args[0] = "sh";
+       args[1] = "-c";
+       args[2] = cmdbuf;
+       args[3] = NULL;
+       status = run_command(&child);
+       if (status < -ERR_RUN_COMMAND_FORK)
+               ; /* failure in run-command */
+       else
+               status = -status;
+       fd = open(temp[1], O_RDONLY);
+       if (fd < 0)
+               goto bad;
+       if (fstat(fd, &st))
+               goto close_bad;
+       result->size = st.st_size;
+       result->ptr = xmalloc(result->size + 1);
+       if (read_in_full(fd, result->ptr, result->size) != result->size) {
+               free(result->ptr);
+               result->ptr = NULL;
+               result->size = 0;
+       }
+  close_bad:
+       close(fd);
+  bad:
+       for (i = 0; i < 3; i++)
+               unlink(temp[i]);
+       return status;
+ }
+ /*
+  * merge.default and merge.driver configuration items
+  */
+ static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
+ static const char *default_ll_merge;
+ static int read_merge_config(const char *var, const char *value)
+ {
+       struct ll_merge_driver *fn;
+       const char *ep, *name;
+       int namelen;
+       if (!strcmp(var, "merge.default")) {
 -                      return error("%s: lacks value", var);
++              if (!value)
++                      return config_error_nonbool(var);
++              default_ll_merge = strdup(value);
+               return 0;
+       }
+       /*
+        * We are not interested in anything but "merge.<name>.variable";
+        * especially, we do not want to look at variables such as
+        * "merge.summary", "merge.tool", and "merge.verbosity".
+        */
+       if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5)
+               return 0;
+       /*
+        * Find existing one as we might be processing merge.<name>.var2
+        * after seeing merge.<name>.var1.
+        */
+       name = var + 6;
+       namelen = ep - name;
+       for (fn = ll_user_merge; fn; fn = fn->next)
+               if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
+                       break;
+       if (!fn) {
+               fn = xcalloc(1, sizeof(struct ll_merge_driver));
+               fn->name = xmemdupz(name, namelen);
+               fn->fn = ll_ext_merge;
+               *ll_user_merge_tail = fn;
+               ll_user_merge_tail = &(fn->next);
+       }
+       ep++;
+       if (!strcmp("name", ep)) {
+               if (!value)
 -                      return error("%s: lacks value", var);
++                      return config_error_nonbool(var);
+               fn->description = strdup(value);
+               return 0;
+       }
+       if (!strcmp("driver", ep)) {
+               if (!value)
 -                      return error("%s: lacks value", var);
++                      return config_error_nonbool(var);
+               /*
+                * merge.<name>.driver specifies the command line:
+                *
+                *      command-line
+                *
+                * The command-line will be interpolated with the following
+                * tokens and is given to the shell:
+                *
+                *    %O - temporary file name for the merge base.
+                *    %A - temporary file name for our version.
+                *    %B - temporary file name for the other branches' version.
+                *
+                * The external merge driver should write the results in the
+                * file named by %A, and signal that it has done with zero exit
+                * status.
+                */
+               fn->cmdline = strdup(value);
+               return 0;
+       }
+       if (!strcmp("recursive", ep)) {
+               if (!value)
++                      return config_error_nonbool(var);
+               fn->recursive = strdup(value);
+               return 0;
+       }
+       return 0;
+ }
+ static void initialize_ll_merge(void)
+ {
+       if (ll_user_merge_tail)
+               return;
+       ll_user_merge_tail = &ll_user_merge;
+       git_config(read_merge_config);
+ }
+ static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
+ {
+       struct ll_merge_driver *fn;
+       const char *name;
+       int i;
+       initialize_ll_merge();
+       if (ATTR_TRUE(merge_attr))
+               return &ll_merge_drv[LL_TEXT_MERGE];
+       else if (ATTR_FALSE(merge_attr))
+               return &ll_merge_drv[LL_BINARY_MERGE];
+       else if (ATTR_UNSET(merge_attr)) {
+               if (!default_ll_merge)
+                       return &ll_merge_drv[LL_TEXT_MERGE];
+               else
+                       name = default_ll_merge;
+       }
+       else
+               name = merge_attr;
+       for (fn = ll_user_merge; fn; fn = fn->next)
+               if (!strcmp(fn->name, name))
+                       return fn;
+       for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
+               if (!strcmp(ll_merge_drv[i].name, name))
+                       return &ll_merge_drv[i];
+       /* default to the 3-way */
+       return &ll_merge_drv[LL_TEXT_MERGE];
+ }
+ static const char *git_path_check_merge(const char *path)
+ {
+       static struct git_attr_check attr_merge_check;
+       if (!attr_merge_check.attr)
+               attr_merge_check.attr = git_attr("merge", 5);
+       if (git_checkattr(path, 1, &attr_merge_check))
+               return NULL;
+       return attr_merge_check.value;
+ }
+ static int ll_merge(mmbuffer_t *result_buf,
+                   struct diff_filespec *o,
+                   struct diff_filespec *a,
+                   struct diff_filespec *b,
+                   const char *branch1,
+                   const char *branch2)
+ {
+       mmfile_t orig, src1, src2;
+       char *name1, *name2;
+       int merge_status;
+       const char *ll_driver_name;
+       const struct ll_merge_driver *driver;
+       name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
+       name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
+       fill_mm(o->sha1, &orig);
+       fill_mm(a->sha1, &src1);
+       fill_mm(b->sha1, &src2);
+       ll_driver_name = git_path_check_merge(a->path);
+       driver = find_ll_merge_driver(ll_driver_name);
+       if (index_only && driver->recursive)
+               driver = find_ll_merge_driver(driver->recursive);
+       merge_status = driver->fn(driver, a->path,
+                                 &orig, &src1, name1, &src2, name2,
+                                 result_buf);
+       free(name1);
+       free(name2);
+       free(orig.ptr);
+       free(src1.ptr);
+       free(src2.ptr);
+       return merge_status;
+ }
+ static struct merge_file_info merge_file(struct diff_filespec *o,
+               struct diff_filespec *a, struct diff_filespec *b,
+               const char *branch1, const char *branch2)
+ {
+       struct merge_file_info result;
+       result.merge = 0;
+       result.clean = 1;
+       if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
+               result.clean = 0;
+               if (S_ISREG(a->mode)) {
+                       result.mode = a->mode;
+                       hashcpy(result.sha, a->sha1);
+               } else {
+                       result.mode = b->mode;
+                       hashcpy(result.sha, b->sha1);
+               }
+       } else {
+               if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
+                       result.merge = 1;
+               result.mode = a->mode == o->mode ? b->mode: a->mode;
+               if (sha_eq(a->sha1, o->sha1))
+                       hashcpy(result.sha, b->sha1);
+               else if (sha_eq(b->sha1, o->sha1))
+                       hashcpy(result.sha, a->sha1);
+               else if (S_ISREG(a->mode)) {
+                       mmbuffer_t result_buf;
+                       int merge_status;
+                       merge_status = ll_merge(&result_buf, o, a, b,
+                                               branch1, branch2);
+                       if ((merge_status < 0) || !result_buf.ptr)
+                               die("Failed to execute internal merge");
+                       if (write_sha1_file(result_buf.ptr, result_buf.size,
+                                           blob_type, result.sha))
+                               die("Unable to add %s to database",
+                                   a->path);
+                       free(result_buf.ptr);
+                       result.clean = (merge_status == 0);
+               } else if (S_ISGITLINK(a->mode)) {
+                       result.clean = 0;
+                       hashcpy(result.sha, a->sha1);
+               } else if (S_ISLNK(a->mode)) {
+                       hashcpy(result.sha, a->sha1);
+                       if (!sha_eq(a->sha1, b->sha1))
+                               result.clean = 0;
+               } else {
+                       die("unsupported object type in the tree");
+               }
+       }
+       return result;
+ }
+ static void conflict_rename_rename(struct rename *ren1,
+                                  const char *branch1,
+                                  struct rename *ren2,
+                                  const char *branch2)
+ {
+       char *del[2];
+       int delp = 0;
+       const char *ren1_dst = ren1->pair->two->path;
+       const char *ren2_dst = ren2->pair->two->path;
+       const char *dst_name1 = ren1_dst;
+       const char *dst_name2 = ren2_dst;
+       if (path_list_has_path(&current_directory_set, ren1_dst)) {
+               dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
+               output(1, "%s is a directory in %s added as %s instead",
+                      ren1_dst, branch2, dst_name1);
+               remove_file(0, ren1_dst, 0);
+       }
+       if (path_list_has_path(&current_directory_set, ren2_dst)) {
+               dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
+               output(1, "%s is a directory in %s added as %s instead",
+                      ren2_dst, branch1, dst_name2);
+               remove_file(0, ren2_dst, 0);
+       }
+       if (index_only) {
+               remove_file_from_cache(dst_name1);
+               remove_file_from_cache(dst_name2);
+               /*
+                * Uncomment to leave the conflicting names in the resulting tree
+                *
+                * update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
+                * update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
+                */
+       } else {
+               update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
+               update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
+       }
+       while (delp--)
+               free(del[delp]);
+ }
+ static void conflict_rename_dir(struct rename *ren1,
+                               const char *branch1)
+ {
+       char *new_path = unique_path(ren1->pair->two->path, branch1);
+       output(1, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
+       remove_file(0, ren1->pair->two->path, 0);
+       update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
+       free(new_path);
+ }
+ static void conflict_rename_rename_2(struct rename *ren1,
+                                    const char *branch1,
+                                    struct rename *ren2,
+                                    const char *branch2)
+ {
+       char *new_path1 = unique_path(ren1->pair->two->path, branch1);
+       char *new_path2 = unique_path(ren2->pair->two->path, branch2);
+       output(1, "Renamed %s to %s and %s to %s instead",
+              ren1->pair->one->path, new_path1,
+              ren2->pair->one->path, new_path2);
+       remove_file(0, ren1->pair->two->path, 0);
+       update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
+       update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
+       free(new_path2);
+       free(new_path1);
+ }
+ static int process_renames(struct path_list *a_renames,
+                          struct path_list *b_renames,
+                          const char *a_branch,
+                          const char *b_branch)
+ {
+       int clean_merge = 1, i, j;
+       struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
+       const struct rename *sre;
+       for (i = 0; i < a_renames->nr; i++) {
+               sre = a_renames->items[i].util;
+               path_list_insert(sre->pair->two->path, &a_by_dst)->util
+                       = sre->dst_entry;
+       }
+       for (i = 0; i < b_renames->nr; i++) {
+               sre = b_renames->items[i].util;
+               path_list_insert(sre->pair->two->path, &b_by_dst)->util
+                       = sre->dst_entry;
+       }
+       for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
+               int compare;
+               char *src;
+               struct path_list *renames1, *renames2, *renames2Dst;
+               struct rename *ren1 = NULL, *ren2 = NULL;
+               const char *branch1, *branch2;
+               const char *ren1_src, *ren1_dst;
+               if (i >= a_renames->nr) {
+                       compare = 1;
+                       ren2 = b_renames->items[j++].util;
+               } else if (j >= b_renames->nr) {
+                       compare = -1;
+                       ren1 = a_renames->items[i++].util;
+               } else {
+                       compare = strcmp(a_renames->items[i].path,
+                                       b_renames->items[j].path);
+                       if (compare <= 0)
+                               ren1 = a_renames->items[i++].util;
+                       if (compare >= 0)
+                               ren2 = b_renames->items[j++].util;
+               }
+               /* TODO: refactor, so that 1/2 are not needed */
+               if (ren1) {
+                       renames1 = a_renames;
+                       renames2 = b_renames;
+                       renames2Dst = &b_by_dst;
+                       branch1 = a_branch;
+                       branch2 = b_branch;
+               } else {
+                       struct rename *tmp;
+                       renames1 = b_renames;
+                       renames2 = a_renames;
+                       renames2Dst = &a_by_dst;
+                       branch1 = b_branch;
+                       branch2 = a_branch;
+                       tmp = ren2;
+                       ren2 = ren1;
+                       ren1 = tmp;
+               }
+               src = ren1->pair->one->path;
+               ren1->dst_entry->processed = 1;
+               ren1->src_entry->processed = 1;
+               if (ren1->processed)
+                       continue;
+               ren1->processed = 1;
+               ren1_src = ren1->pair->one->path;
+               ren1_dst = ren1->pair->two->path;
+               if (ren2) {
+                       const char *ren2_src = ren2->pair->one->path;
+                       const char *ren2_dst = ren2->pair->two->path;
+                       /* Renamed in 1 and renamed in 2 */
+                       if (strcmp(ren1_src, ren2_src) != 0)
+                               die("ren1.src != ren2.src");
+                       ren2->dst_entry->processed = 1;
+                       ren2->processed = 1;
+                       if (strcmp(ren1_dst, ren2_dst) != 0) {
+                               clean_merge = 0;
+                               output(1, "CONFLICT (rename/rename): "
+                                      "Rename \"%s\"->\"%s\" in branch \"%s\" "
+                                      "rename \"%s\"->\"%s\" in \"%s\"%s",
+                                      src, ren1_dst, branch1,
+                                      src, ren2_dst, branch2,
+                                      index_only ? " (left unresolved)": "");
+                               if (index_only) {
+                                       remove_file_from_cache(src);
+                                       update_file(0, ren1->pair->one->sha1,
+                                                   ren1->pair->one->mode, src);
+                               }
+                               conflict_rename_rename(ren1, branch1, ren2, branch2);
+                       } else {
+                               struct merge_file_info mfi;
+                               remove_file(1, ren1_src, 1);
+                               mfi = merge_file(ren1->pair->one,
+                                                ren1->pair->two,
+                                                ren2->pair->two,
+                                                branch1,
+                                                branch2);
+                               if (mfi.merge || !mfi.clean)
+                                       output(1, "Renamed %s->%s", src, ren1_dst);
+                               if (mfi.merge)
+                                       output(2, "Auto-merged %s", ren1_dst);
+                               if (!mfi.clean) {
+                                       output(1, "CONFLICT (content): merge conflict in %s",
+                                              ren1_dst);
+                                       clean_merge = 0;
+                                       if (!index_only)
+                                               update_stages(ren1_dst,
+                                                             ren1->pair->one,
+                                                             ren1->pair->two,
+                                                             ren2->pair->two,
+                                                             1 /* clear */);
+                               }
+                               update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
+                       }
+               } else {
+                       /* Renamed in 1, maybe changed in 2 */
+                       struct path_list_item *item;
+                       /* we only use sha1 and mode of these */
+                       struct diff_filespec src_other, dst_other;
+                       int try_merge, stage = a_renames == renames1 ? 3: 2;
+                       remove_file(1, ren1_src, index_only || stage == 3);
+                       hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
+                       src_other.mode = ren1->src_entry->stages[stage].mode;
+                       hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
+                       dst_other.mode = ren1->dst_entry->stages[stage].mode;
+                       try_merge = 0;
+                       if (path_list_has_path(&current_directory_set, ren1_dst)) {
+                               clean_merge = 0;
+                               output(1, "CONFLICT (rename/directory): Renamed %s->%s in %s "
+                                      " directory %s added in %s",
+                                      ren1_src, ren1_dst, branch1,
+                                      ren1_dst, branch2);
+                               conflict_rename_dir(ren1, branch1);
+                       } else if (sha_eq(src_other.sha1, null_sha1)) {
+                               clean_merge = 0;
+                               output(1, "CONFLICT (rename/delete): Renamed %s->%s in %s "
+                                      "and deleted in %s",
+                                      ren1_src, ren1_dst, branch1,
+                                      branch2);
+                               update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
+                       } else if (!sha_eq(dst_other.sha1, null_sha1)) {
+                               const char *new_path;
+                               clean_merge = 0;
+                               try_merge = 1;
+                               output(1, "CONFLICT (rename/add): Renamed %s->%s in %s. "
+                                      "%s added in %s",
+                                      ren1_src, ren1_dst, branch1,
+                                      ren1_dst, branch2);
+                               new_path = unique_path(ren1_dst, branch2);
+                               output(1, "Added as %s instead", new_path);
+                               update_file(0, dst_other.sha1, dst_other.mode, new_path);
+                       } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
+                               ren2 = item->util;
+                               clean_merge = 0;
+                               ren2->processed = 1;
+                               output(1, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
+                                      "Renamed %s->%s in %s",
+                                      ren1_src, ren1_dst, branch1,
+                                      ren2->pair->one->path, ren2->pair->two->path, branch2);
+                               conflict_rename_rename_2(ren1, branch1, ren2, branch2);
+                       } else
+                               try_merge = 1;
+                       if (try_merge) {
+                               struct diff_filespec *o, *a, *b;
+                               struct merge_file_info mfi;
+                               src_other.path = (char *)ren1_src;
+                               o = ren1->pair->one;
+                               if (a_renames == renames1) {
+                                       a = ren1->pair->two;
+                                       b = &src_other;
+                               } else {
+                                       b = ren1->pair->two;
+                                       a = &src_other;
+                               }
+                               mfi = merge_file(o, a, b,
+                                               a_branch, b_branch);
+                               if (mfi.clean &&
+                                   sha_eq(mfi.sha, ren1->pair->two->sha1) &&
+                                   mfi.mode == ren1->pair->two->mode)
+                                       /*
+                                        * This messaged is part of
+                                        * t6022 test. If you change
+                                        * it update the test too.
+                                        */
+                                       output(3, "Skipped %s (merged same as existing)", ren1_dst);
+                               else {
+                                       if (mfi.merge || !mfi.clean)
+                                               output(1, "Renamed %s => %s", ren1_src, ren1_dst);
+                                       if (mfi.merge)
+                                               output(2, "Auto-merged %s", ren1_dst);
+                                       if (!mfi.clean) {
+                                               output(1, "CONFLICT (rename/modify): Merge conflict in %s",
+                                                      ren1_dst);
+                                               clean_merge = 0;
+                                               if (!index_only)
+                                                       update_stages(ren1_dst,
+                                                                     o, a, b, 1);
+                                       }
+                                       update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
+                               }
+                       }
+               }
+       }
+       path_list_clear(&a_by_dst, 0);
+       path_list_clear(&b_by_dst, 0);
+       return clean_merge;
+ }
+ static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
+ {
+       return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
+ }
+ /* Per entry merge function */
+ static int process_entry(const char *path, struct stage_data *entry,
+                        const char *branch1,
+                        const char *branch2)
+ {
+       /*
+       printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
+       print_index_entry("\tpath: ", entry);
+       */
+       int clean_merge = 1;
+       unsigned o_mode = entry->stages[1].mode;
+       unsigned a_mode = entry->stages[2].mode;
+       unsigned b_mode = entry->stages[3].mode;
+       unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
+       unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
+       unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
+       if (o_sha && (!a_sha || !b_sha)) {
+               /* Case A: Deleted in one */
+               if ((!a_sha && !b_sha) ||
+                   (sha_eq(a_sha, o_sha) && !b_sha) ||
+                   (!a_sha && sha_eq(b_sha, o_sha))) {
+                       /* Deleted in both or deleted in one and
+                        * unchanged in the other */
+                       if (a_sha)
+                               output(2, "Removed %s", path);
+                       /* do not touch working file if it did not exist */
+                       remove_file(1, path, !a_sha);
+               } else {
+                       /* Deleted in one and changed in the other */
+                       clean_merge = 0;
+                       if (!a_sha) {
+                               output(1, "CONFLICT (delete/modify): %s deleted in %s "
+                                      "and modified in %s. Version %s of %s left in tree.",
+                                      path, branch1,
+                                      branch2, branch2, path);
+                               update_file(0, b_sha, b_mode, path);
+                       } else {
+                               output(1, "CONFLICT (delete/modify): %s deleted in %s "
+                                      "and modified in %s. Version %s of %s left in tree.",
+                                      path, branch2,
+                                      branch1, branch1, path);
+                               update_file(0, a_sha, a_mode, path);
+                       }
+               }
+       } else if ((!o_sha && a_sha && !b_sha) ||
+                  (!o_sha && !a_sha && b_sha)) {
+               /* Case B: Added in one. */
+               const char *add_branch;
+               const char *other_branch;
+               unsigned mode;
+               const unsigned char *sha;
+               const char *conf;
+               if (a_sha) {
+                       add_branch = branch1;
+                       other_branch = branch2;
+                       mode = a_mode;
+                       sha = a_sha;
+                       conf = "file/directory";
+               } else {
+                       add_branch = branch2;
+                       other_branch = branch1;
+                       mode = b_mode;
+                       sha = b_sha;
+                       conf = "directory/file";
+               }
+               if (path_list_has_path(&current_directory_set, path)) {
+                       const char *new_path = unique_path(path, add_branch);
+                       clean_merge = 0;
+                       output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
+                              "Added %s as %s",
+                              conf, path, other_branch, path, new_path);
+                       remove_file(0, path, 0);
+                       update_file(0, sha, mode, new_path);
+               } else {
+                       output(2, "Added %s", path);
+                       update_file(1, sha, mode, path);
+               }
+       } else if (a_sha && b_sha) {
+               /* Case C: Added in both (check for same permissions) and */
+               /* case D: Modified in both, but differently. */
+               const char *reason = "content";
+               struct merge_file_info mfi;
+               struct diff_filespec o, a, b;
+               if (!o_sha) {
+                       reason = "add/add";
+                       o_sha = (unsigned char *)null_sha1;
+               }
+               output(2, "Auto-merged %s", path);
+               o.path = a.path = b.path = (char *)path;
+               hashcpy(o.sha1, o_sha);
+               o.mode = o_mode;
+               hashcpy(a.sha1, a_sha);
+               a.mode = a_mode;
+               hashcpy(b.sha1, b_sha);
+               b.mode = b_mode;
+               mfi = merge_file(&o, &a, &b,
+                                branch1, branch2);
+               clean_merge = mfi.clean;
+               if (mfi.clean)
+                       update_file(1, mfi.sha, mfi.mode, path);
+               else if (S_ISGITLINK(mfi.mode))
+                       output(1, "CONFLICT (submodule): Merge conflict in %s "
+                              "- needs %s", path, sha1_to_hex(b.sha1));
+               else {
+                       output(1, "CONFLICT (%s): Merge conflict in %s",
+                                       reason, path);
+                       if (index_only)
+                               update_file(0, mfi.sha, mfi.mode, path);
+                       else
+                               update_file_flags(mfi.sha, mfi.mode, path,
+                                             0 /* update_cache */, 1 /* update_working_directory */);
+               }
+       } else if (!o_sha && !a_sha && !b_sha) {
+               /*
+                * this entry was deleted altogether. a_mode == 0 means
+                * we had that path and want to actively remove it.
+                */
+               remove_file(1, path, !a_mode);
+       } else
+               die("Fatal merge failure, shouldn't happen.");
+       return clean_merge;
+ }
+ int merge_trees(struct tree *head,
+               struct tree *merge,
+               struct tree *common,
+               const char *branch1,
+               const char *branch2,
+               struct tree **result)
+ {
+       int code, clean;
+       if (subtree_merge) {
+               merge = shift_tree_object(head, merge);
+               common = shift_tree_object(head, common);
+       }
+       if (sha_eq(common->object.sha1, merge->object.sha1)) {
+               output(0, "Already uptodate!");
+               *result = head;
+               return 1;
+       }
+       code = git_merge_trees(index_only, common, head, merge);
+       if (code != 0)
+               die("merging of trees %s and %s failed",
+                   sha1_to_hex(head->object.sha1),
+                   sha1_to_hex(merge->object.sha1));
+       if (unmerged_cache()) {
+               struct path_list *entries, *re_head, *re_merge;
+               int i;
+               path_list_clear(&current_file_set, 1);
+               path_list_clear(&current_directory_set, 1);
+               get_files_dirs(head);
+               get_files_dirs(merge);
+               entries = get_unmerged();
+               re_head  = get_renames(head, common, head, merge, entries);
+               re_merge = get_renames(merge, common, head, merge, entries);
+               clean = process_renames(re_head, re_merge,
+                               branch1, branch2);
+               for (i = 0; i < entries->nr; i++) {
+                       const char *path = entries->items[i].path;
+                       struct stage_data *e = entries->items[i].util;
+                       if (!e->processed
+                               && !process_entry(path, e, branch1, branch2))
+                               clean = 0;
+               }
+               path_list_clear(re_merge, 0);
+               path_list_clear(re_head, 0);
+               path_list_clear(entries, 1);
+       }
+       else
+               clean = 1;
+       if (index_only)
+               *result = write_tree_from_memory();
+       return clean;
+ }
+ static struct commit_list *reverse_commit_list(struct commit_list *list)
+ {
+       struct commit_list *next = NULL, *current, *backup;
+       for (current = list; current; current = backup) {
+               backup = current->next;
+               current->next = next;
+               next = current;
+       }
+       return next;
+ }
+ /*
+  * Merge the commits h1 and h2, return the resulting virtual
+  * commit object and a flag indicating the cleanness of the merge.
+  */
+ int merge_recursive(struct commit *h1,
+                   struct commit *h2,
+                   const char *branch1,
+                   const char *branch2,
+                   struct commit_list *ca,
+                   struct commit **result)
+ {
+       struct commit_list *iter;
+       struct commit *merged_common_ancestors;
+       struct tree *mrtree = mrtree;
+       int clean;
+       if (show(4)) {
+               output(4, "Merging:");
+               output_commit_title(h1);
+               output_commit_title(h2);
+       }
+       if (!ca) {
+               ca = get_merge_bases(h1, h2, 1);
+               ca = reverse_commit_list(ca);
+       }
+       if (show(5)) {
+               output(5, "found %u common ancestor(s):", commit_list_count(ca));
+               for (iter = ca; iter; iter = iter->next)
+                       output_commit_title(iter->item);
+       }
+       merged_common_ancestors = pop_commit(&ca);
+       if (merged_common_ancestors == NULL) {
+               /* if there is no common ancestor, make an empty tree */
+               struct tree *tree = xcalloc(1, sizeof(struct tree));
+               tree->object.parsed = 1;
+               tree->object.type = OBJ_TREE;
+               pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
+               merged_common_ancestors = make_virtual_commit(tree, "ancestor");
+       }
+       for (iter = ca; iter; iter = iter->next) {
+               call_depth++;
+               /*
+                * When the merge fails, the result contains files
+                * with conflict markers. The cleanness flag is
+                * ignored, it was never actually used, as result of
+                * merge_trees has always overwritten it: the committed
+                * "conflicts" were already resolved.
+                */
+               discard_cache();
+               merge_recursive(merged_common_ancestors, iter->item,
+                               "Temporary merge branch 1",
+                               "Temporary merge branch 2",
+                               NULL,
+                               &merged_common_ancestors);
+               call_depth--;
+               if (!merged_common_ancestors)
+                       die("merge returned no commit");
+       }
+       discard_cache();
+       if (!call_depth) {
+               read_cache();
+               index_only = 0;
+       } else
+               index_only = 1;
+       clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
+                           branch1, branch2, &mrtree);
+       if (index_only) {
+               *result = make_virtual_commit(mrtree, "merged tree");
+               commit_list_insert(h1, &(*result)->parents);
+               commit_list_insert(h2, &(*result)->parents->next);
+       }
+       flush_output();
+       return clean;
+ }
+ static const char *better_branch_name(const char *branch)
+ {
+       static char githead_env[8 + 40 + 1];
+       char *name;
+       if (strlen(branch) != 40)
+               return branch;
+       sprintf(githead_env, "GITHEAD_%s", branch);
+       name = getenv(githead_env);
+       return name ? name : branch;
+ }
+ static struct commit *get_ref(const char *ref)
+ {
+       unsigned char sha1[20];
+       struct object *object;
+       if (get_sha1(ref, sha1))
+               die("Could not resolve ref '%s'", ref);
+       object = deref_tag(parse_object(sha1), ref, strlen(ref));
++      if (!object)
++              return NULL;
+       if (object->type == OBJ_TREE)
+               return make_virtual_commit((struct tree*)object,
+                       better_branch_name(ref));
+       if (object->type != OBJ_COMMIT)
+               return NULL;
+       if (parse_commit((struct commit *)object))
+               die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
+       return (struct commit *)object;
+ }
+ static int merge_config(const char *var, const char *value)
+ {
+       if (!strcasecmp(var, "merge.verbosity")) {
+               verbosity = git_config_int(var, value);
+               return 0;
+       }
+       if (!strcasecmp(var, "diff.renamelimit")) {
+               rename_limit = git_config_int(var, value);
+               return 0;
+       }
+       return git_default_config(var, value);
+ }
+ int cmd_merge_recursive(int argc, const char **argv, const char *prefix)
+ {
+       static const char *bases[20];
+       static unsigned bases_count = 0;
+       int i, clean;
+       const char *branch1, *branch2;
+       struct commit *result, *h1, *h2;
+       struct commit_list *ca = NULL;
+       struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
+       int index_fd;
+       if (argv[0]) {
+               int namelen = strlen(argv[0]);
+               if (8 < namelen &&
+                   !strcmp(argv[0] + namelen - 8, "-subtree"))
+                       subtree_merge = 1;
+       }
+       git_config(merge_config);
+       if (getenv("GIT_MERGE_VERBOSITY"))
+               verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
+       if (argc < 4)
+               die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
+       for (i = 1; i < argc; ++i) {
+               if (!strcmp(argv[i], "--"))
+                       break;
+               if (bases_count < sizeof(bases)/sizeof(*bases))
+                       bases[bases_count++] = argv[i];
+       }
+       if (argc - i != 3) /* "--" "<head>" "<remote>" */
+               die("Not handling anything other than two heads merge.");
+       if (verbosity >= 5)
+               buffer_output = 0;
+       branch1 = argv[++i];
+       branch2 = argv[++i];
+       h1 = get_ref(branch1);
+       h2 = get_ref(branch2);
+       branch1 = better_branch_name(branch1);
+       branch2 = better_branch_name(branch2);
+       if (show(3))
+               printf("Merging %s with %s\n", branch1, branch2);
+       index_fd = hold_locked_index(lock, 1);
+       for (i = 0; i < bases_count; i++) {
+               struct commit *ancestor = get_ref(bases[i]);
+               ca = commit_list_insert(ancestor, &ca);
+       }
+       clean = merge_recursive(h1, h2, branch1, branch2, ca, &result);
+       if (active_cache_changed &&
+           (write_cache(index_fd, active_cache, active_nr) ||
+            commit_locked_index(lock)))
+                       die ("unable to write %s", get_index_file());
+       return clean ? 0: 1;
+ }
Simple merge
diff --cc builtin.h
Simple merge
diff --cc cache.h
Simple merge
index 0000000000000000000000000000000000000000,5621c69d86062c7c75c0b8c2749d34efc78cafb4..1a7689a48f07a6ed2bb156f745bfea19a10e3eb9
mode 000000,100755..100755
--- /dev/null
@@@ -1,0 -1,298 +1,302 @@@
 -if rev=$(git rev-parse --verify "$arg^0" 2>/dev/null)
+ #!/bin/sh
+ OPTIONS_KEEPDASHDASH=t
+ OPTIONS_SPEC="\
+ git-checkout [options] [<branch>] [<paths>...]
+ --
+ b=          create a new branch started at <branch>
+ l           create the new branch's reflog
+ track       arrange that the new branch tracks the remote branch
+ f           proceed even if the index or working tree is not HEAD
+ m           merge local modifications into the new branch
+ q,quiet     be quiet
+ "
+ SUBDIRECTORY_OK=Sometimes
+ . git-sh-setup
+ require_work_tree
+ old_name=HEAD
+ old=$(git rev-parse --verify $old_name 2>/dev/null)
+ oldbranch=$(git symbolic-ref $old_name 2>/dev/null)
+ new=
+ new_name=
+ force=
+ branch=
+ track=
+ newbranch=
+ newbranch_log=
+ merge=
+ quiet=
+ v=-v
+ LF='
+ '
+ while test $# != 0; do
+       case "$1" in
+       -b)
+               shift
+               newbranch="$1"
+               [ -z "$newbranch" ] &&
+                       die "git checkout: -b needs a branch name"
+               git show-ref --verify --quiet -- "refs/heads/$newbranch" &&
+                       die "git checkout: branch $newbranch already exists"
+               git check-ref-format "heads/$newbranch" ||
+                       die "git checkout: we do not like '$newbranch' as a branch name."
+               ;;
+       -l)
+               newbranch_log=-l
+               ;;
+       --track|--no-track)
+               track="$1"
+               ;;
+       -f)
+               force=1
+               ;;
+       -m)
+               merge=1
+               ;;
+       -q|--quiet)
+               quiet=1
+               v=
+               ;;
+       --)
+               shift
+               break
+               ;;
+       *)
+               usage
+               ;;
+       esac
+       shift
+ done
+ arg="$1"
 -elif rev=$(git rev-parse --verify "$arg^{tree}" 2>/dev/null)
++rev=$(git rev-parse --verify "$arg" 2>/dev/null)
++if rev=$(git rev-parse --verify "$rev^0" 2>/dev/null)
+ then
+       [ -z "$rev" ] && die "unknown flag $arg"
+       new_name="$arg"
+       if git show-ref --verify --quiet -- "refs/heads/$arg"
+       then
+               rev=$(git rev-parse --verify "refs/heads/$arg^0")
+               branch="$arg"
+       fi
+       new="$rev"
+       shift
 -      new_name="$arg^{tree}"
++elif rev=$(git rev-parse --verify "$rev^{tree}" 2>/dev/null)
+ then
+       # checking out selected paths from a tree-ish.
+       new="$rev"
 -    merge_error=$(git read-tree -m -u --exclude-per-directory=.gitignore $old $new 2>&1) || (
 -      case "$merge" in
 -      '')
 -              echo >&2 "$merge_error"
++      new_name="$rev^{tree}"
+       shift
+ fi
+ [ "$1" = "--" ] && shift
+ case "$newbranch,$track" in
+ ,--*)
+       die "git checkout: --track and --no-track require -b"
+ esac
+ case "$force$merge" in
+ 11)
+       die "git checkout: -f and -m are incompatible"
+ esac
+ # The behaviour of the command with and without explicit path
+ # parameters is quite different.
+ #
+ # Without paths, we are checking out everything in the work tree,
+ # possibly switching branches.  This is the traditional behaviour.
+ #
+ # With paths, we are _never_ switching branch, but checking out
+ # the named paths from either index (when no rev is given),
+ # or the named tree-ish (when rev is given).
+ if test "$#" -ge 1
+ then
+       hint=
+       if test "$#" -eq 1
+       then
+               hint="
+ Did you intend to checkout '$@' which can not be resolved as commit?"
+       fi
+       if test '' != "$newbranch$force$merge"
+       then
+               die "git checkout: updating paths is incompatible with switching branches/forcing$hint"
+       fi
+       if test '' != "$new"
+       then
+               # from a specific tree-ish; note that this is for
+               # rescuing paths and is never meant to remove what
+               # is not in the named tree-ish.
+               git ls-tree --full-name -r "$new" "$@" |
+               git update-index --index-info || exit $?
+       fi
+       # Make sure the request is about existing paths.
+       git ls-files --full-name --error-unmatch -- "$@" >/dev/null || exit
+       git ls-files --full-name -- "$@" |
+               (cd_to_toplevel && git checkout-index -f -u --stdin)
+       # Run a post-checkout hook -- the HEAD does not change so the
+       # current HEAD is passed in for both args
+       if test -x "$GIT_DIR"/hooks/post-checkout; then
+           "$GIT_DIR"/hooks/post-checkout $old $old 0
+       fi
+       exit $?
+ else
+       # Make sure we did not fall back on $arg^{tree} codepath
+       # since we are not checking out from an arbitrary tree-ish,
+       # but switching branches.
+       if test '' != "$new"
+       then
+               git rev-parse --verify "$new^{commit}" >/dev/null 2>&1 ||
+               die "Cannot switch branch to a non-commit."
+       fi
+ fi
+ # We are switching branches and checking out trees, so
+ # we *NEED* to be at the toplevel.
+ cd_to_toplevel
+ [ -z "$new" ] && new=$old && new_name="$old_name"
+ # If we don't have an existing branch that we're switching to,
+ # and we don't have a new branch name for the target we
+ # are switching to, then we are detaching our HEAD from any
+ # branch.  However, if "git checkout HEAD" detaches the HEAD
+ # from the current branch, even though that may be logically
+ # correct, it feels somewhat funny.  More importantly, we do not
+ # want "git checkout" nor "git checkout -f" to detach HEAD.
+ detached=
+ detach_warn=
+ describe_detached_head () {
+       test -n "$quiet" || {
+               printf >&2 "$1 "
+               GIT_PAGER= git log >&2 -1 --pretty=oneline --abbrev-commit "$2" --
+       }
+ }
+ if test -z "$branch$newbranch" && test "$new_name" != "$old_name"
+ then
+       detached="$new"
+       if test -n "$oldbranch" && test -z "$quiet"
+       then
+               detach_warn="Note: moving to \"$new_name\" which isn't a local branch
+ If you want to create a new branch from this checkout, you may do so
+ (now or later) by using -b with the checkout command again. Example:
+   git checkout -b <new_branch_name>"
+       fi
+ elif test -z "$oldbranch" && test "$new" != "$old"
+ then
+       describe_detached_head 'Previous HEAD position was' "$old"
+ fi
+ if [ "X$old" = X ]
+ then
+       if test -z "$quiet"
+       then
+               echo >&2 "warning: You appear to be on a branch yet to be born."
+               echo >&2 "warning: Forcing checkout of $new_name."
+       fi
+       force=1
+ fi
+ if [ "$force" ]
+ then
+     git read-tree $v --reset -u $new
+ else
+     git update-index --refresh >/dev/null
++    git read-tree $v -m -u --exclude-per-directory=.gitignore $old $new || (
++      case "$merge,$v" in
++      ,*)
+               exit 1 ;;
++      1,)
++              ;; # quiet
++      *)
++              echo >&2 "Falling back to 3-way merge..." ;;
+       esac
+       # Match the index to the working tree, and do a three-way.
+       git diff-files --name-only | git update-index --remove --stdin &&
+       work=`git write-tree` &&
+       git read-tree $v --reset -u $new || exit
+       eval GITHEAD_$new='${new_name:-${branch:-$new}}' &&
+       eval GITHEAD_$work=local &&
+       export GITHEAD_$new GITHEAD_$work &&
+       git merge-recursive $old -- $new $work
+       # Do not register the cleanly merged paths in the index yet.
+       # this is not a real merge before committing, but just carrying
+       # the working tree changes along.
+       unmerged=`git ls-files -u`
+       git read-tree $v --reset $new
+       case "$unmerged" in
+       '')     ;;
+       *)
+               (
+                       z40=0000000000000000000000000000000000000000
+                       echo "$unmerged" |
+                       sed -e 's/^[0-7]* [0-9a-f]* /'"0 $z40 /"
+                       echo "$unmerged"
+               ) | git update-index --index-info
+               ;;
+       esac
+       exit 0
+     )
+     saved_err=$?
+     if test "$saved_err" = 0 && test -z "$quiet"
+     then
+       git diff-index --name-status "$new"
+     fi
+     (exit $saved_err)
+ fi
+ #
+ # Switch the HEAD pointer to the new branch if we
+ # checked out a branch head, and remove any potential
+ # old MERGE_HEAD's (subsequent commits will clearly not
+ # be based on them, since we re-set the index)
+ #
+ if [ "$?" -eq 0 ]; then
+       if [ "$newbranch" ]; then
+               git branch $track $newbranch_log "$newbranch" "$new_name" || exit
+               branch="$newbranch"
+       fi
+       if test -n "$branch"
+       then
+               old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
+               GIT_DIR="$GIT_DIR" git symbolic-ref -m "checkout: moving from ${old_branch_name:-$old} to $branch" HEAD "refs/heads/$branch"
+               if test -n "$quiet"
+               then
+                       true    # nothing
+               elif test "refs/heads/$branch" = "$oldbranch"
+               then
+                       echo >&2 "Already on branch \"$branch\""
+               else
+                       echo >&2 "Switched to${newbranch:+ a new} branch \"$branch\""
+               fi
+       elif test -n "$detached"
+       then
+               old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'`
+               git update-ref --no-deref -m "checkout: moving from ${old_branch_name:-$old} to $arg" HEAD "$detached" ||
+                       die "Cannot detach HEAD"
+               if test -n "$detach_warn"
+               then
+                       echo >&2 "$detach_warn"
+               fi
+               describe_detached_head 'HEAD is now at' HEAD
+       fi
+       rm -f "$GIT_DIR/MERGE_HEAD"
+ else
+       exit 1
+ fi
+ # Run a post-checkout hook
+ if test -x "$GIT_DIR"/hooks/post-checkout; then
+       "$GIT_DIR"/hooks/post-checkout $old $new 1
+ fi
diff --cc git.c
Simple merge
diff --cc read-cache.c
Simple merge
diff --cc t/t7201-co.sh
Simple merge
diff --cc unpack-trees.c
index 56c1ffbc199c534a53da9615aa16b4357656e320,470fa02e0886462f44fd0e188da6e8c65ab6fac0..3e448d8974eb6d738fec2c35cc5a9ffbc8764411
@@@ -590,9 -624,10 +625,10 @@@ static int merged_entry(struct cache_en
                 * a match.
                 */
                if (same(old, merge)) {
 -                      memcpy(merge, old, offsetof(struct cache_entry, name));
 +                      copy_cache_entry(merge, old);
                } else {
-                       verify_uptodate(old, o);
+                       if (verify_uptodate(old, o))
+                               return -1;
                        invalidate_ce_path(old);
                }
        }