git-branch: add options and tests for branch renaming

Extend git-branch with the following options:

  git-branch -m|-M [<oldbranch>] newbranch

The -M variation is required to force renaming over an exsisting
branchname.

This also indroduces $GIT_DIR/RENAME_REF which is a "metabranch"
used when renaming branches. It will always hold the original sha1
for the latest renamed branch.

Additionally, if $GIT_DIR/logs/RENAME_REF exists, all branch rename
events are logged there.

Finally, some testcases are added to verify the new options.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt
index 4f5b5d5028e15f693440baa57358ab4c898994e8..71417feba8f4987bb9d7565ec58f82044d343283 100644 (file)
--- a/Documentation/git-branch.txt
+++ b/Documentation/git-branch.txt
@@ -8,8 +8,9 @@ git-branch - List, create, or delete branches.
 SYNOPSIS
 --------
 [verse]
-'git-branch' [-r] [-a] [-v] [--abbrev=<length>]
+'git-branch' [-r | -a] [-v [--abbrev=<length>]]
 'git-branch' [-l] [-f] <branchname> [<start-point>]
+'git-branch' (-m | -M) [<oldbranch>] <newbranch>
 'git-branch' (-d | -D) <branchname>...
 
 DESCRIPTION
@@ -24,6 +25,12 @@ It will start out with a head equal to the one given as <start-point>.
 If no <start-point> is given, the branch will be created with a head
 equal to that of the currently checked out branch.
 
+With a '-m' or '-M' option, <oldbranch> will be renamed to <newbranch>.
+If <oldbranch> had a corresponding reflog, it is renamed to match
+<newbranch>, and a reflog entry is created to remember the branch
+renaming. If <newbranch> exists, -M must be used to force the rename
+to happen.
+
 With a `-d` or `-D` option, `<branchname>` will be deleted.  You may
 specify more than one branch for deletion.  If the branch currently
 has a ref log then the ref log will also be deleted.
@@ -46,6 +53,12 @@ OPTIONS
        Force the creation of a new branch even if it means deleting
        a branch that already exists with the same name.
 
+-m::
+       Move/rename a branch and the corresponding reflog.
+
+-M::
+       Move/rename a branch even if the new branchname already exists.
+
 -r::
        List the remote-tracking branches.
 
@@ -53,7 +66,7 @@ OPTIONS
        List both remote-tracking branches and local branches.
 
 -v::
-       Show sha1 and subject message for each head.
+       Show sha1 and commit subjectline for each head.
 
 --abbrev=<length>::
        Alter minimum display length for sha1 in output listing,
@@ -70,6 +83,12 @@ OPTIONS
        be given as a branch name, a commit-id, or a tag.  If this option
        is omitted, the current branch is assumed.
 
+<oldbranch>::
+       The name of an existing branch to rename.
+
+<newbranch>::
+       The new name for an existing branch. The same restrictions as for
+       <branchname> applies.
 
 
 Examples

diff --git a/builtin-branch.c b/builtin-branch.c
index 3d5cb0e4b2de8abf3a9f1af8fadb9c1bc5393967..153682601e2f77514edab0e6ba9d3077cd3114e7 100644 (file)
--- a/builtin-branch.c
+++ b/builtin-branch.c
@@ -11,7 +11,7 @@
 #include "builtin.h"
 
 static const char builtin_branch_usage[] =
-"git-branch (-d | -D) <branchname> | [-l] [-f] <branchname> [<start-point>] | [-r | -a] [-v] [--abbrev=<length>] ";
+  "git-branch (-d | -D) <branchname> | [-l] [-f] <branchname> [<start-point>] | (-m | -M) [<oldbranch>] <newbranch> | [-r | -a] [-v [--abbrev=<length>]]";
 
 
 static const char *head;
@@ -245,9 +245,37 @@ static void create_branch(const char *name, const char *start,
                die("Failed to write ref: %s.", strerror(errno));
 }
 
+static void rename_branch(const char *oldname, const char *newname, int force)
+{
+       char oldref[PATH_MAX], newref[PATH_MAX];
+       unsigned char sha1[20];
+
+       if (snprintf(oldref, sizeof(oldref), "refs/heads/%s", oldname) > sizeof(oldref))
+               die("Old branchname too long");
+
+       if (check_ref_format(oldref))
+               die("Invalid branch name: %s", oldref);
+
+       if (snprintf(newref, sizeof(newref), "refs/heads/%s", newname) > sizeof(newref))
+               die("New branchname too long");
+
+       if (check_ref_format(newref))
+               die("Invalid branch name: %s", newref);
+
+       if (resolve_ref(newref, sha1, 1, NULL) && !force)
+               die("A branch named '%s' already exists.", newname);
+
+       if (rename_ref(oldref, newref))
+               die("Branch rename failed");
+
+       if (!strcmp(oldname, head) && create_symref("HEAD", newref))
+               die("Branch renamed to %s, but HEAD is not updated!", newname);
+}
+
 int cmd_branch(int argc, const char **argv, const char *prefix)
 {
        int delete = 0, force_delete = 0, force_create = 0;
+       int rename = 0, force_rename = 0;
        int verbose = 0, abbrev = DEFAULT_ABBREV;
        int reflog = 0;
        int kinds = REF_LOCAL_BRANCH;
@@ -277,6 +305,15 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
                        force_create = 1;
                        continue;
                }
+               if (!strcmp(arg, "-m")) {
+                       rename = 1;
+                       continue;
+               }
+               if (!strcmp(arg, "-M")) {
+                       rename = 1;
+                       force_rename = 1;
+                       continue;
+               }
                if (!strcmp(arg, "-r")) {
                        kinds = REF_REMOTE_BRANCH;
                        continue;
@@ -300,6 +337,10 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
                usage(builtin_branch_usage);
        }
 
+       if ((delete && rename) || (delete && force_create) ||
+           (rename && force_create))
+               usage(builtin_branch_usage);
+
        head = xstrdup(resolve_ref("HEAD", head_sha1, 0, NULL));
        if (!head)
                die("Failed to resolve HEAD as a valid ref.");
@@ -311,6 +352,10 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
                delete_branches(argc - i, argv + i, force_delete);
        else if (i == argc)
                print_ref_list(kinds, verbose, abbrev);
+       else if (rename && (i == argc - 1))
+               rename_branch(head, argv[i], force_rename);
+       else if (rename && (i == argc - 2))
+               rename_branch(argv[i], argv[i + 1], force_rename);
        else if (i == argc - 1)
                create_branch(argv[i], head, force_create, reflog);
        else if (i == argc - 2)

diff --git a/refs.c b/refs.c
index 96ea8b6907b1e4be9c7b8575ff7e4a36f5a7a5f8..cdedb45f00d2a9c379b5cfbf78086f8d2f9eaba1 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -610,6 +610,29 @@ static int remove_empty_directories(char *file)
        return remove_empty_dir_recursive(path, len);
 }
 
+static int is_refname_available(const char *ref, const char *oldref,
+                               struct ref_list *list, int quiet)
+{
+       int namlen = strlen(ref); /* e.g. 'foo/bar' */
+       while (list) {
+               /* list->name could be 'foo' or 'foo/bar/baz' */
+               if (!oldref || strcmp(oldref, list->name)) {
+                       int len = strlen(list->name);
+                       int cmplen = (namlen < len) ? namlen : len;
+                       const char *lead = (namlen < len) ? list->name : ref;
+                       if (!strncmp(ref, list->name, cmplen) &&
+                           lead[cmplen] == '/') {
+                               if (!quiet)
+                                       error("'%s' exists; cannot create '%s'",
+                                             list->name, ref);
+                               return 0;
+                       }
+               }
+               list = list->next;
+       }
+       return 1;
+}
+
 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int *flag)
 {
        char *ref_file;
@@ -643,29 +666,14 @@ static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char
                        orig_ref, strerror(errno));
                goto error_return;
        }
-       if (is_null_sha1(lock->old_sha1)) {
-               /* The ref did not exist and we are creating it.
-                * Make sure there is no existing ref that is packed
-                * whose name begins with our refname, nor a ref whose
-                * name is a proper prefix of our refname.
-                */
-               int namlen = strlen(ref); /* e.g. 'foo/bar' */
-               struct ref_list *list = get_packed_refs();
-               while (list) {
-                       /* list->name could be 'foo' or 'foo/bar/baz' */
-                       int len = strlen(list->name);
-                       int cmplen = (namlen < len) ? namlen : len;
-                       const char *lead = (namlen < len) ? list->name : ref;
-
-                       if (!strncmp(ref, list->name, cmplen) &&
-                           lead[cmplen] == '/') {
-                               error("'%s' exists; cannot create '%s'",
-                                     list->name, ref);
-                               goto error_return;
-                       }
-                       list = list->next;
-               }
-       }
+       /* When the ref did not exist and we are creating it,
+        * make sure there is no existing ref that is packed
+        * whose name begins with our refname, nor a ref whose
+        * name is a proper prefix of our refname.
+        */
+       if (is_null_sha1(lock->old_sha1) &&
+            !is_refname_available(ref, NULL, get_packed_refs(), 0))
+               goto error_return;
 
        lock->lk = xcalloc(1, sizeof(struct lock_file));
 
@@ -776,6 +784,121 @@ int delete_ref(const char *refname, unsigned char *sha1)
        return ret;
 }
 
+int rename_ref(const char *oldref, const char *newref)
+{
+       static const char renamed_ref[] = "RENAMED-REF";
+       unsigned char sha1[20], orig_sha1[20];
+       int flag = 0, logmoved = 0;
+       struct ref_lock *lock;
+       char msg[PATH_MAX*2 + 100];
+       struct stat loginfo;
+       int log = !stat(git_path("logs/%s", oldref), &loginfo);
+
+       if (S_ISLNK(loginfo.st_mode))
+               return error("reflog for %s is a symlink", oldref);
+
+       if (!resolve_ref(oldref, orig_sha1, 1, &flag))
+               return error("refname %s not found", oldref);
+
+       if (!is_refname_available(newref, oldref, get_packed_refs(), 0))
+               return 1;
+
+       if (!is_refname_available(newref, oldref, get_loose_refs(), 0))
+               return 1;
+
+       if (snprintf(msg, sizeof(msg), "renamed %s to %s", oldref, newref) > sizeof(msg))
+               return error("Refnames to long");
+
+       lock = lock_ref_sha1_basic(renamed_ref, NULL, NULL);
+       if (!lock)
+               return error("unable to lock %s", renamed_ref);
+       lock->force_write = 1;
+       if (write_ref_sha1(lock, orig_sha1, msg))
+               return error("unable to save current sha1 in %s", renamed_ref);
+
+       if (log && rename(git_path("logs/%s", oldref), git_path("tmp-renamed-log")))
+               return error("unable to move logfile logs/%s to tmp-renamed-log: %s",
+                       oldref, strerror(errno));
+
+       if (delete_ref(oldref, orig_sha1)) {
+               error("unable to delete old %s", oldref);
+               goto rollback;
+       }
+
+       if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1)) {
+               if (errno==EISDIR) {
+                       if (remove_empty_directories(git_path("%s", newref))) {
+                               error("Directory not empty: %s", newref);
+                               goto rollback;
+                       }
+               } else {
+                       error("unable to delete existing %s", newref);
+                       goto rollback;
+               }
+       }
+
+       if (log && safe_create_leading_directories(git_path("logs/%s", newref))) {
+               error("unable to create directory for %s", newref);
+               goto rollback;
+       }
+
+ retry:
+       if (log && rename(git_path("tmp-renamed-log"), git_path("logs/%s", newref))) {
+               if (errno==EISDIR) {
+                       if (remove_empty_directories(git_path("logs/%s", newref))) {
+                               error("Directory not empty: logs/%s", newref);
+                               goto rollback;
+                       }
+                       goto retry;
+               } else {
+                       error("unable to move logfile tmp-renamed-log to logs/%s: %s",
+                               newref, strerror(errno));
+                       goto rollback;
+               }
+       }
+       logmoved = log;
+
+       lock = lock_ref_sha1_basic(newref, NULL, NULL);
+       if (!lock) {
+               error("unable to lock %s for update", newref);
+               goto rollback;
+       }
+
+       lock->force_write = 1;
+       hashcpy(lock->old_sha1, orig_sha1);
+       if (write_ref_sha1(lock, orig_sha1, msg)) {
+               error("unable to write current sha1 into %s", newref);
+               goto rollback;
+       }
+
+       return 0;
+
+ rollback:
+       lock = lock_ref_sha1_basic(oldref, NULL, NULL);
+       if (!lock) {
+               error("unable to lock %s for rollback", oldref);
+               goto rollbacklog;
+       }
+
+       lock->force_write = 1;
+       flag = log_all_ref_updates;
+       log_all_ref_updates = 0;
+       if (write_ref_sha1(lock, orig_sha1, NULL))
+               error("unable to write current sha1 into %s", oldref);
+       log_all_ref_updates = flag;
+
+ rollbacklog:
+       if (logmoved && rename(git_path("logs/%s", newref), git_path("logs/%s", oldref)))
+               error("unable to restore logfile %s from %s: %s",
+                       oldref, newref, strerror(errno));
+       if (!logmoved && log &&
+           rename(git_path("tmp-renamed-log"), git_path("logs/%s", oldref)))
+               error("unable to restore logfile %s from tmp-renamed-log: %s",
+                       oldref, strerror(errno));
+
+       return 1;
+}
+
 void unlock_ref(struct ref_lock *lock)
 {
        if (lock->lock_fd >= 0) {

diff --git a/refs.h b/refs.h
index cd1e1d620e6513cd1542d15763ccd5c07f108e48..ce73d5c7ae394c012f828536dd4df8b143819718 100644 (file)
--- a/refs.h
+++ b/refs.h
@@ -47,4 +47,7 @@ extern int read_ref_at(const char *ref, unsigned long at_time, int cnt, unsigned
 /** Returns 0 if target has the right format for a ref. **/
 extern int check_ref_format(const char *target);
 
+/** rename ref, return 0 on success **/
+extern int rename_ref(const char *oldref, const char *newref);
+
 #endif /* REFS_H */

diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index acb54b6a079b2e790c3bf6eb58007188af7ef1a1..afaa8536a9342d6597e82dc8b96ad8b9becafad6 100755 (executable)
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -70,4 +70,38 @@ test_expect_success \
         git-branch -d l/m &&
         git-branch l'
 
+test_expect_success \
+    'git branch -m m m/m should work' \
+       'git-branch -l m &&
+        git-branch -m m m/m &&
+        test -f .git/logs/refs/heads/m/m'
+
+test_expect_success \
+    'git branch -m n/n n should work' \
+       'git-branch -l n/n &&
+        git-branch -m n/n n
+        test -f .git/logs/refs/heads/n'
+
+test_expect_failure \
+    'git branch -m o/o o should fail when o/p exists' \
+       'git-branch o/o &&
+        git-branch o/p &&
+        git-branch -m o/o o'
+
+test_expect_failure \
+    'git branch -m q r/q should fail when r exists' \
+       'git-branch q &&
+         git-branch r &&
+         git-branch -m q r/q'
+
+test_expect_success \
+    'git branch -m s/s s should work when s/t is deleted' \
+       'git-branch -l s/s &&
+        test -f .git/logs/refs/heads/s/s &&
+        git-branch -l s/t &&
+        test -f .git/logs/refs/heads/s/t &&
+        git-branch -d s/t &&
+        git-branch -m s/s s &&
+        test -f .git/logs/refs/heads/s'
+
 test_done