tag: keep the message file in case ref transaction fails

The ref transaction can fail after the user has written their tag
message. In particular, if there exists a tag `foo/bar` and `git tag -a
foo` is said then the command will only fail once it tries to write
`refs/tags/foo`, which is after the file has been unlinked.

Hold on to the message file for a little longer so that it is not
unlinked before the fatal error occurs.

Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/tag.c b/builtin/tag.c
index 1850a6a6fdcf82f18ad3f1f1aefd5d22fc527e3f..49b64c7a2883b586015931869acf3878f33de299 100644 (file)
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -271,11 +271,10 @@ static const char message_advice_nested_tag[] =
 static void create_tag(const struct object_id *object, const char *object_ref,
                       const char *tag,
                       struct strbuf *buf, struct create_tag_options *opt,
-                      struct object_id *prev, struct object_id *result)
+                      struct object_id *prev, struct object_id *result, char *path)
 {
        enum object_type type;
        struct strbuf header = STRBUF_INIT;
-       char *path = NULL;
 
        type = oid_object_info(the_repository, object, NULL);
        if (type <= OBJ_NONE)
@@ -299,7 +298,6 @@ static void create_tag(const struct object_id *object, const char *object_ref,
                int fd;
 
                /* write the template message before editing: */
-               path = git_pathdup("TAG_EDITMSG");
                fd = xopen(path, O_CREAT | O_TRUNC | O_WRONLY, 0600);
 
                if (opt->message_given) {
@@ -341,10 +339,6 @@ static void create_tag(const struct object_id *object, const char *object_ref,
                                path);
                exit(128);
        }
-       if (path) {
-               unlink_or_warn(path);
-               free(path);
-       }
 }
 
 static void create_reflog_msg(const struct object_id *oid, struct strbuf *sb)
@@ -495,6 +489,7 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
        };
        int ret = 0;
        const char *only_in_list = NULL;
+       char *path = NULL;
 
        setup_ref_filter_porcelain_msg();
 
@@ -629,7 +624,9 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
        if (create_tag_object) {
                if (force_sign_annotate && !annotate)
                        opt.sign = 1;
-               create_tag(&object, object_ref, tag, &buf, &opt, &prev, &object);
+               path = git_pathdup("TAG_EDITMSG");
+               create_tag(&object, object_ref, tag, &buf, &opt, &prev, &object,
+                          path);
        }
 
        transaction = ref_transaction_begin(&err);
@@ -637,8 +634,17 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
            ref_transaction_update(transaction, ref.buf, &object, &prev,
                                   create_reflog ? REF_FORCE_CREATE_REFLOG : 0,
                                   reflog_msg.buf, &err) ||
-           ref_transaction_commit(transaction, &err))
+           ref_transaction_commit(transaction, &err)) {
+               if (path)
+                       fprintf(stderr,
+                               _("The tag message has been left in %s\n"),
+                               path);
                die("%s", err.buf);
+       }
+       if (path) {
+               unlink_or_warn(path);
+               free(path);
+       }
        ref_transaction_free(transaction);
        if (force && !is_null_oid(&prev) && !oideq(&prev, &object))
                printf(_("Updated tag '%s' (was %s)\n"), tag,

diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index 13937c36421f0168fe057f53f3edfedd1361fbc7..e689db429292e60162d4f8f89905cc8489d7a3e0 100755 (executable)
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh
@@ -2197,4 +2197,14 @@ test_expect_success 'If tag is created then tag message file is unlinked' '
        test_path_is_missing .git/TAG_EDITMSG
 '
 
+test_expect_success 'If tag cannot be created then tag message file is not unlinked' '
+       test_when_finished "git tag -d foo/bar && rm .git/TAG_EDITMSG" &&
+       write_script fakeeditor <<-\EOF &&
+       echo Message >.git/TAG_EDITMSG
+       EOF
+       git tag foo/bar &&
+       test_must_fail env GIT_EDITOR=./fakeeditor git tag -a foo &&
+       test_path_exists .git/TAG_EDITMSG
+'
+
 test_done