Merge remote branch 'ko/master' into jc/read-tree-cache-tree-fix

* ko/master: (2325 commits)
  Git 1.7.2-rc2
  backmerge a few more fixes to 1.7.1.X series
  fix git branch -m in presence of cross devices
  t/t0006: specify timezone as EST5 not EST to comply with POSIX
  add missing && to submodule-merge testcase
  t/README: document more test helpers
  test-date: fix sscanf type conversion
  xdiff: optimise for no whitespace difference when ignoring whitespace.
  gitweb: Move evaluate_gitweb_config out of run_request
  parse_date: fix signedness in timezone calculation
  t0006: test timezone parsing
  rerere.txt: Document forget subcommand
  t/README: proposed rewording...
  t/README: Document the do's and don'ts of tests
  t/README: Add a section about skipping tests
  t/README: Document test_expect_code
  t/README: Document test_external*
  t/README: Document the prereq functions, and 3-arg test_*
  t/README: Typo: paralell -> parallel
  t/README: The trash is in 't/trash directory.$name'
  ...

Conflicts:
	builtin-read-tree.c

diff --cc builtin/read-tree.c
index 0000000000000000000000000000000000000000,8bdcab11389e8b4facab355f27f0e1926134b86f..9ad1e66916545dd2aeeb110661e56edfa5921019
mode 000000,100644..100644
--- /dev/null
--- 2/builtin/read-tree.c
+++ b/builtin/read-tree.c
@@@ -1,0 -1,235 +1,230 @@@
 -       *
 -       * The same holds true if we are switching between two trees
 -       * using read-tree -m A B.  The index must match B after that.
+ /*
+  * GIT - The information manager from hell
+  *
+  * Copyright (C) Linus Torvalds, 2005
+  */
+ 
+ #include "cache.h"
+ #include "object.h"
+ #include "tree.h"
+ #include "tree-walk.h"
+ #include "cache-tree.h"
+ #include "unpack-trees.h"
+ #include "dir.h"
+ #include "builtin.h"
+ #include "parse-options.h"
+ #include "resolve-undo.h"
+ 
+ static int nr_trees;
+ static struct tree *trees[MAX_UNPACK_TREES];
+ 
+ static int list_tree(unsigned char *sha1)
+ {
+       struct tree *tree;
+ 
+       if (nr_trees >= MAX_UNPACK_TREES)
+               die("I cannot read more than %d trees", MAX_UNPACK_TREES);
+       tree = parse_tree_indirect(sha1);
+       if (!tree)
+               return -1;
+       trees[nr_trees++] = tree;
+       return 0;
+ }
+ 
+ static const char * const read_tree_usage[] = {
+       "git read-tree [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>] [-u [--exclude-per-directory=<gitignore>] | -i]] [--no-sparse-checkout] [--index-output=<file>] <tree-ish1> [<tree-ish2> [<tree-ish3>]]",
+       NULL
+ };
+ 
+ static int index_output_cb(const struct option *opt, const char *arg,
+                                int unset)
+ {
+       set_alternate_index_output(arg);
+       return 0;
+ }
+ 
+ static int exclude_per_directory_cb(const struct option *opt, const char *arg,
+                                   int unset)
+ {
+       struct dir_struct *dir;
+       struct unpack_trees_options *opts;
+ 
+       opts = (struct unpack_trees_options *)opt->value;
+ 
+       if (opts->dir)
+               die("more than one --exclude-per-directory given.");
+ 
+       dir = xcalloc(1, sizeof(*opts->dir));
+       dir->flags |= DIR_SHOW_IGNORED;
+       dir->exclude_per_dir = arg;
+       opts->dir = dir;
+       /* We do not need to nor want to do read-directory
+        * here; we are merely interested in reusing the
+        * per directory ignore stack mechanism.
+        */
+       return 0;
+ }
+ 
+ static void debug_stage(const char *label, struct cache_entry *ce,
+                       struct unpack_trees_options *o)
+ {
+       printf("%s ", label);
+       if (!ce)
+               printf("(missing)\n");
+       else if (ce == o->df_conflict_entry)
+               printf("(conflict)\n");
+       else
+               printf("%06o #%d %s %.8s\n",
+                      ce->ce_mode, ce_stage(ce), ce->name,
+                      sha1_to_hex(ce->sha1));
+ }
+ 
+ static int debug_merge(struct cache_entry **stages, struct unpack_trees_options *o)
+ {
+       int i;
+ 
+       printf("* %d-way merge\n", o->merge_size);
+       debug_stage("index", stages[0], o);
+       for (i = 1; i <= o->merge_size; i++) {
+               char buf[24];
+               sprintf(buf, "ent#%d", i);
+               debug_stage(buf, stages[i], o);
+       }
+       return 0;
+ }
+ 
+ static struct lock_file lock_file;
+ 
+ int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
+ {
+       int i, newfd, stage = 0;
+       unsigned char sha1[20];
+       struct tree_desc t[MAX_UNPACK_TREES];
+       struct unpack_trees_options opts;
+       int prefix_set = 0;
+       const struct option read_tree_options[] = {
+               { OPTION_CALLBACK, 0, "index-output", NULL, "FILE",
+                 "write resulting index to <FILE>",
+                 PARSE_OPT_NONEG, index_output_cb },
+               OPT__VERBOSE(&opts.verbose_update),
+               OPT_GROUP("Merging"),
+               OPT_SET_INT('m', NULL, &opts.merge,
+                           "perform a merge in addition to a read", 1),
+               OPT_SET_INT(0, "trivial", &opts.trivial_merges_only,
+                           "3-way merge if no file level merging required", 1),
+               OPT_SET_INT(0, "aggressive", &opts.aggressive,
+                           "3-way merge in presence of adds and removes", 1),
+               OPT_SET_INT(0, "reset", &opts.reset,
+                           "same as -m, but discard unmerged entries", 1),
+               { OPTION_STRING, 0, "prefix", &opts.prefix, "<subdirectory>/",
+                 "read the tree into the index under <subdirectory>/",
+                 PARSE_OPT_NONEG | PARSE_OPT_LITERAL_ARGHELP },
+               OPT_SET_INT('u', NULL, &opts.update,
+                           "update working tree with merge result", 1),
+               { OPTION_CALLBACK, 0, "exclude-per-directory", &opts,
+                 "gitignore",
+                 "allow explicitly ignored files to be overwritten",
+                 PARSE_OPT_NONEG, exclude_per_directory_cb },
+               OPT_SET_INT('i', NULL, &opts.index_only,
+                           "don't check the working tree after merging", 1),
+               OPT_SET_INT(0, "no-sparse-checkout", &opts.skip_sparse_checkout,
+                           "skip applying sparse checkout filter", 1),
+               OPT_SET_INT(0, "debug-unpack", &opts.debug_unpack,
+                           "debug unpack-trees", 1),
+               OPT_END()
+       };
+ 
+       memset(&opts, 0, sizeof(opts));
+       opts.head_idx = -1;
+       opts.src_index = &the_index;
+       opts.dst_index = &the_index;
+ 
+       git_config(git_default_config, NULL);
+ 
+       argc = parse_options(argc, argv, unused_prefix, read_tree_options,
+                            read_tree_usage, 0);
+ 
+       newfd = hold_locked_index(&lock_file, 1);
+ 
+       prefix_set = opts.prefix ? 1 : 0;
+       if (1 < opts.merge + opts.reset + prefix_set)
+               die("Which one? -m, --reset, or --prefix?");
+ 
+       if (opts.reset || opts.merge || opts.prefix) {
+               if (read_cache_unmerged() && (opts.prefix || opts.merge))
+                       die("You need to resolve your current index first");
+               stage = opts.merge = 1;
+       }
+       resolve_undo_clear();
+ 
+       for (i = 0; i < argc; i++) {
+               const char *arg = argv[i];
+ 
+               if (get_sha1(arg, sha1))
+                       die("Not a valid object name %s", arg);
+               if (list_tree(sha1) < 0)
+                       die("failed to unpack tree object %s", arg);
+               stage++;
+       }
+       if (1 < opts.index_only + opts.update)
+               die("-u and -i at the same time makes no sense");
+       if ((opts.update||opts.index_only) && !opts.merge)
+               die("%s is meaningless without -m, --reset, or --prefix",
+                   opts.update ? "-u" : "-i");
+       if ((opts.dir && !opts.update))
+               die("--exclude-per-directory is meaningless unless -u");
+       if (opts.merge && !opts.index_only)
+               setup_work_tree();
+ 
+       if (opts.merge) {
+               if (stage < 2)
+                       die("just how do you expect me to merge %d trees?", stage-1);
+               switch (stage - 1) {
+               case 1:
+                       opts.fn = opts.prefix ? bind_merge : oneway_merge;
+                       break;
+               case 2:
+                       opts.fn = twoway_merge;
+                       opts.initial_checkout = is_cache_unborn();
+                       break;
+               case 3:
+               default:
+                       opts.fn = threeway_merge;
+                       break;
+               }
+ 
+               if (stage - 1 >= 3)
+                       opts.head_idx = stage - 2;
+               else
+                       opts.head_idx = 1;
+       }
+ 
+       if (opts.debug_unpack)
+               opts.fn = debug_merge;
+ 
+       cache_tree_free(&active_cache_tree);
+       for (i = 0; i < nr_trees; i++) {
+               struct tree *tree = trees[i];
+               parse_tree(tree);
+               init_tree_desc(t+i, tree->buffer, tree->size);
+       }
+       if (unpack_trees(nr_trees, t, &opts))
+               return 128;
+ 
+       if (opts.debug_unpack)
+               return 0; /* do not write the index out */
+ 
+       /*
+        * When reading only one tree (either the most basic form,
+        * "-m ent" or "--reset ent" form), we can obtain a fully
+        * valid cache-tree because the index must match exactly
+        * what came from the tree.
 -      else if (nr_trees == 2 && opts.merge)
 -              prime_cache_tree(&active_cache_tree, trees[1]);
+        */
+       if (nr_trees == 1 && !opts.prefix)
+               prime_cache_tree(&active_cache_tree, trees[0]);
+ 
+       if (write_cache(newfd, active_cache, active_nr) ||
+           commit_locked_index(&lock_file))
+               die("unable to write new index file");
+       return 0;
+ }

diff --cc t/t1001-read-tree-m-2way.sh
Simple merge