Teach the "@{-1} syntax to "git branch"

This teaches the new "@{-1} syntax to refer to the previous branch to "git
branch".  After looking at somebody's faulty patch series on a topic
branch too long, if you decide it is not worth merging, you can just say:

    $ git checkout master
    $ git branch -D @{-1}

to get rid of it without having to type the name of the topic you now hate
so much for wasting a lot of your time.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/branch.c b/branch.c
index b1ac837f3d30c826ddbe29492b906bf2d0de0a1a..1f00e44deb28afe74ae4f0b85b23039476032fe5 100644 (file)
--- a/branch.c
+++ b/branch.c
@@ -103,14 +103,22 @@ void create_branch(const char *head,
        struct ref_lock *lock;
        struct commit *commit;
        unsigned char sha1[20];
-       char *real_ref, ref[PATH_MAX], msg[PATH_MAX + 20];
+       char *real_ref, msg[PATH_MAX + 20];
+       struct strbuf ref = STRBUF_INIT;
        int forcing = 0;
+       int len;
 
-       snprintf(ref, sizeof ref, "refs/heads/%s", name);
-       if (check_ref_format(ref))
+       len = strlen(name);
+       if (interpret_nth_last_branch(name, &ref) != len) {
+               strbuf_reset(&ref);
+               strbuf_add(&ref, name, len);
+       }
+       strbuf_splice(&ref, 0, 0, "refs/heads/", 11);
+
+       if (check_ref_format(ref.buf))
                die("'%s' is not a valid branch name.", name);
 
-       if (resolve_ref(ref, sha1, 1, NULL)) {
+       if (resolve_ref(ref.buf, sha1, 1, NULL)) {
                if (!force)
                        die("A branch named '%s' already exists.", name);
                else if (!is_bare_repository() && !strcmp(head, name))
@@ -142,7 +150,7 @@ void create_branch(const char *head,
                die("Not a valid branch point: '%s'.", start_name);
        hashcpy(sha1, commit->object.sha1);
 
-       lock = lock_any_ref_for_update(ref, NULL, 0);
+       lock = lock_any_ref_for_update(ref.buf, NULL, 0);
        if (!lock)
                die("Failed to lock ref for update: %s.", strerror(errno));
 
@@ -162,6 +170,7 @@ void create_branch(const char *head,
        if (write_ref_sha1(lock, sha1, msg) < 0)
                die("Failed to write ref: %s.", strerror(errno));
 
+       strbuf_release(&ref);
        free(real_ref);
 }
 

diff --git a/builtin-branch.c b/builtin-branch.c
index 56a1971d690e32ca1cb0bc2d66ee05be48bfe565..504a981ad56f73a547c11bf3e18185f67111d000 100644 (file)
--- a/builtin-branch.c
+++ b/builtin-branch.c
@@ -99,6 +99,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds)
        const char *fmt, *remote;
        int i;
        int ret = 0;
+       struct strbuf bname = STRBUF_INIT;
 
        switch (kinds) {
        case REF_REMOTE_BRANCH:
@@ -119,20 +120,25 @@ static int delete_branches(int argc, const char **argv, int force, int kinds)
                if (!head_rev)
                        die("Couldn't look up commit object for HEAD");
        }
-       for (i = 0; i < argc; i++) {
-               if (kinds == REF_LOCAL_BRANCH && !strcmp(head, argv[i])) {
+       for (i = 0; i < argc; i++, strbuf_release(&bname)) {
+               int len = strlen(argv[i]);
+
+               if (interpret_nth_last_branch(argv[i], &bname) != len)
+                       strbuf_add(&bname, argv[i], len);
+
+               if (kinds == REF_LOCAL_BRANCH && !strcmp(head, bname.buf)) {
                        error("Cannot delete the branch '%s' "
-                               "which you are currently on.", argv[i]);
+                             "which you are currently on.", bname.buf);
                        ret = 1;
                        continue;
                }
 
                free(name);
 
-               name = xstrdup(mkpath(fmt, argv[i]));
+               name = xstrdup(mkpath(fmt, bname.buf));
                if (!resolve_ref(name, sha1, 1, NULL)) {
                        error("%sbranch '%s' not found.",
-                                       remote, argv[i]);
+                                       remote, bname.buf);
                        ret = 1;
                        continue;
                }
@@ -152,22 +158,23 @@ static int delete_branches(int argc, const char **argv, int force, int kinds)
                if (!force &&
                    !in_merge_bases(rev, &head_rev, 1)) {
                        error("The branch '%s' is not an ancestor of "
-                               "your current HEAD.\n"
-                               "If you are sure you want to delete it, "
-                               "run 'git branch -D %s'.", argv[i], argv[i]);
+                             "your current HEAD.\n"
+                             "If you are sure you want to delete it, "
+                             "run 'git branch -D %s'.", bname.buf, bname.buf);
                        ret = 1;
                        continue;
                }
 
                if (delete_ref(name, sha1, 0)) {
                        error("Error deleting %sbranch '%s'", remote,
-                              argv[i]);
+                             bname.buf);
                        ret = 1;
                } else {
                        struct strbuf buf = STRBUF_INIT;
-                       printf("Deleted %sbranch %s (%s).\n", remote, argv[i],
-                               find_unique_abbrev(sha1, DEFAULT_ABBREV));
-                       strbuf_addf(&buf, "branch.%s", argv[i]);
+                       printf("Deleted %sbranch %s (%s).\n", remote,
+                              bname.buf,
+                              find_unique_abbrev(sha1, DEFAULT_ABBREV));
+                       strbuf_addf(&buf, "branch.%s", bname.buf);
                        if (git_config_rename_section(buf.buf, NULL) < 0)
                                warning("Update of config-file failed");
                        strbuf_release(&buf);

diff --git a/t/t0100-previous.sh b/t/t0100-previous.sh
new file mode 100755 (executable)
index 0000000..db51b42
--- /dev/null
+++ b/t/t0100-previous.sh
@@ -0,0 +1,26 @@
+#!/bin/sh
+
+test_description='previous branch syntax @{-n}'
+
+. ./test-lib.sh
+
+test_expect_success 'branch -d @{-1}' '
+       test_commit A &&
+       git checkout -b junk &&
+       git checkout - &&
+       test "$(git symbolic-ref HEAD)" = refs/heads/master &&
+       git branch -d @{-1} &&
+       test_must_fail git rev-parse --verify refs/heads/junk
+'
+
+test_expect_success 'branch -d @{-12} when there is not enough switches yet' '
+       git reflog expire --expire=now &&
+       git checkout -b junk2 &&
+       git checkout - &&
+       test "$(git symbolic-ref HEAD)" = refs/heads/master &&
+       test_must_fail git branch -d @{-12} &&
+       git rev-parse --verify refs/heads/master
+'
+
+test_done
+