From: Luke Shumaker <lukeshu@xxxxxxxxxxx>
A tag object contains the tag-name in the object, and is also pointed
to by a ref named 'refs/tags/{tag-name}'. It's possible to end up
with a tag for which the internal name and the refname disagree.
This "shouldn't" happen, but sometimes it can. In the "the coolest
merge ever"[1], if Linus had wanted to import existing tags from
Paul's gitk repo, he'd likely have wanted to give them a `gitk/` or
`gitk-` prefix; you don't want gitk v0.0.1 to appear to be git v0.0.1,
so when importing it, you'd rename the tag to `gitk/v0.0.1`.
(Less hypothetically, my employer's repo has _several_ such
merges/imports, where the tags from each repo were given a prefix.)
That'd work fine if they're lightweight tags, but if they're annotated
tags, then after the rename the internal name in the tag object
(`v0.0.1`) is now different than the refname (`gitk/v0.0.1`). Which
is still mostly fine, since not too many tools care if the internal
name and the refname disagree.
But, fast-export/fast-import are tools that do care: it's currently
impossible to represent these tags in a fast-import stream.
This patch adds an optional "name" sub-command to fast-import's "tag"
top-level-command, the stream
tag foo
name bar
...
will create a tag at "refs/tags/foo" that says "tag bar" internally.
These tags are things that "shouldn't" happen, so perhaps adding
support for them to fast-export/fast-import is unwelcome, which is why
I've marked this as an "RFC". If this addition is welcome, then it
still needs tests and documentation.
[1]: https://lore.kernel.org/git/Pine.LNX.4.58.0506221433540.2353@xxxxxxxxxxxxxxx/
---
Documentation/git-fast-import.txt | 1 +
builtin/fast-export.c | 25 ++++++++++++++++++-------
builtin/fast-import.c | 11 +++++++++--
3 files changed, 28 insertions(+), 9 deletions(-)
diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt
index 39cfa05b28..6514b42d28 100644
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@ -824,6 +824,7 @@ lightweight (non-annotated) tags see the `reset` command below.
....
'tag' SP <name> LF
mark?
+ ('name' SP <name> LF)?
'from' SP <commit-ish> LF
original-oid?
'tagger' (SP <name>)? SP LT <email> GT SP <when> LF
diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index 85a76e0ef8..48e207a445 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -767,12 +767,13 @@ static void handle_tail(struct object_array *commits, struct rev_info *revs,
}
}
-static void handle_tag(const char *name, struct tag *tag)
+static void handle_tag(const char *refname, struct tag *tag)
{
unsigned long size;
enum object_type type;
char *buf;
- const char *tagger, *tagger_end, *message;
+ const char *refbasename;
+ const char *tagname, *tagname_end, *tagger, *tagger_end, *message;
size_t message_size = 0;
struct object *tagged;
int tagged_mark;
@@ -800,6 +801,11 @@ static void handle_tag(const char *name, struct tag *tag)
message += 2;
message_size = strlen(message);
}
+ tagname = memmem(buf, message ? message - buf : size, "\ntag ", 5);
+ if (!tagname)
+ die("malformed tag %s", oid_to_hex(&tag->object.oid));
+ tagname += 5;
+ tagname_end = strchrnul(tagname, '\n');
tagger = memmem(buf, message ? message - buf : size, "\ntagger ", 8);
if (!tagger) {
if (fake_missing_tagger)
@@ -816,7 +822,7 @@ static void handle_tag(const char *name, struct tag *tag)
}
if (anonymize) {
- name = anonymize_refname(name);
+ refname = anonymize_refname(refname);
if (message) {
static struct hashmap tags;
message = anonymize_str(&tags, anonymize_tag,
@@ -870,7 +876,7 @@ static void handle_tag(const char *name, struct tag *tag)
p = rewrite_commit((struct commit *)tagged);
if (!p) {
printf("reset %s\nfrom %s\n\n",
- name, oid_to_hex(&null_oid));
+ refname, oid_to_hex(&null_oid));
free(buf);
return;
}
@@ -884,14 +890,19 @@ static void handle_tag(const char *name, struct tag *tag)
if (tagged->type == OBJ_TAG) {
printf("reset %s\nfrom %s\n\n",
- name, oid_to_hex(&null_oid));
+ refname, oid_to_hex(&null_oid));
}
- skip_prefix(name, "refs/tags/", &name);
- printf("tag %s\n", name);
+ refbasename = refname;
+ skip_prefix(refbasename, "refs/tags/", &refbasename);
+ printf("tag %s\n", refbasename);
if (mark_tags) {
mark_next_object(&tag->object);
printf("mark :%"PRIu32"\n", last_idnum);
}
+ if ((size_t)(tagname_end - tagname) != strlen(refbasename) ||
+ strncmp(tagname, refbasename, (size_t)(tagname_end - tagname)))
+ printf("name %.*s\n",
+ (int)(tagname_end - tagname), tagname);
if (tagged_mark)
printf("from :%d\n", tagged_mark);
else
diff --git a/builtin/fast-import.c b/builtin/fast-import.c
index 3afa81cf9a..24bdd46cba 100644
--- a/builtin/fast-import.c
+++ b/builtin/fast-import.c
@@ -2783,7 +2783,7 @@ static void parse_new_commit(const char *arg)
static void parse_new_tag(const char *arg)
{
static struct strbuf msg = STRBUF_INIT;
- const char *from;
+ const char *name, *from;
char *tagger;
struct branch *s;
struct tag *t;
@@ -2803,6 +2803,13 @@ static void parse_new_tag(const char *arg)
read_next_command();
parse_mark();
+ /* name ... */
+ if (skip_prefix(command_buf.buf, "name ", &v)) {
+ name = strdupa(v);
+ read_next_command();
+ } else
+ name = NULL;
+
/* from ... */
if (!skip_prefix(command_buf.buf, "from ", &from))
die("Expected from command, got %s", command_buf.buf);
@@ -2850,7 +2857,7 @@ static void parse_new_tag(const char *arg)
"object %s\n"
"type %s\n"
"tag %s\n",
- oid_to_hex(&oid), type_name(type), t->name);
+ oid_to_hex(&oid), type_name(type), name ? name : t->name);
if (tagger)
strbuf_addf(&new_data,
"tagger %s\n", tagger);
--
2.31.1
Happy hacking,
~ Luke Shumaker
