fast-import: fix handling of deleted tags

If our input stream includes a tag which is later deleted, we were not
properly deleting it.  We did have a step which would delete it, but we
left a tag in the tag list noting that it needed to be updated, and the
updating of annotated tags occurred AFTER ref deletion.  So, when we
record that a tag needs to be deleted, also remove it from the list of
annotated tags to update.

While this has likely been something that has not happened in practice,
it will come up more in order to support nested tags.  For nested tags,
we either need to give temporary names to the intermediate tags and then
delete them, or else we need to use the final name for the intermediate
tags.  If we use the final name for the intermediate tags, then in order
to keep the sanity check that someone doesn't try to update the same tag
twice, we need to delete the ref after creating the intermediate tag.
So, either way nested tags imply the need to delete temporary inner tag
references.

Helped-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/fast-import.c b/fast-import.c
index b44d6a467ef17f3d2f541475ab1f4ce968504a5e..caae0819f59357721be2f43f72afdade2af2d6cd 100644 (file)
--- a/fast-import.c
+++ b/fast-import.c
@@ -2778,6 +2778,7 @@ static void parse_new_tag(const char *arg)
 static void parse_reset_branch(const char *arg)
 {
        struct branch *b;
+       const char *tag_name;
 
        b = lookup_branch(arg);
        if (b) {
@@ -2793,6 +2794,32 @@ static void parse_reset_branch(const char *arg)
                b = new_branch(arg);
        read_next_command();
        parse_from(b);
+       if (b->delete && skip_prefix(b->name, "refs/tags/", &tag_name)) {
+               /*
+                * Elsewhere, we call dump_branches() before dump_tags(),
+                * and dump_branches() will handle ref deletions first, so
+                * in order to make sure the deletion actually takes effect,
+                * we need to remove the tag from our list of tags to update.
+                *
+                * NEEDSWORK: replace list of tags with hashmap for faster
+                * deletion?
+                */
+               struct tag *t, *prev = NULL;
+               for (t = first_tag; t; t = t->next_tag) {
+                       if (!strcmp(t->name, tag_name))
+                               break;
+                       prev = t;
+               }
+               if (t) {
+                       if (prev)
+                               prev->next_tag = t->next_tag;
+                       else
+                               first_tag = t->next_tag;
+                       if (!t->next_tag)
+                               last_tag = prev;
+                       /* There is no mem_pool_free(t) function to call. */
+               }
+       }
        if (command_buf.len > 0)
                unread_command_buf = 1;
 }

diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index 141b7fa35e74b860d91ea7cdabf48730442ed635..74bc41333b9944bc3d312606b6343de486ccf184 100755 (executable)
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -85,6 +85,15 @@ test_expect_success 'A: create pack from stdin' '
        An annotated tag that annotates a blob.
        EOF
 
+       tag to-be-deleted
+       from :3
+       data <<EOF
+       Another annotated tag that annotates a blob.
+       EOF
+
+       reset refs/tags/to-be-deleted
+       from 0000000000000000000000000000000000000000
+
        INPUT_END
        git fast-import --export-marks=marks.out <input &&
        git whatchanged master
@@ -157,6 +166,10 @@ test_expect_success 'A: verify tag/series-A-blob' '
        test_cmp expect actual
 '
 
+test_expect_success 'A: verify tag deletion is successful' '
+       test_must_fail git rev-parse --verify refs/tags/to-be-deleted
+'
+
 test_expect_success 'A: verify marks output' '
        cat >expect <<-EOF &&
        :2 $(git rev-parse --verify master:file2)