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, in-the-wild, my employer's
repo has _several_ such merges/imports, where the tags from each repo
were given a prefix.)
- Sometimes tags are "archived" to something like
"refs/archived-tags/foo".
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 "refname" sub-command to fast-import's "tag"
top-level-command, the stream
tag foo
refname refs/tags/bar
...
will create a tag at "refs/tags/bar" that says "tag foo" internally.
[1]: https://lore.kernel.org/git/Pine.LNX.4.58.0506221433540.2353@xxxxxxxxxxxxxxx/
Signed-off-by: Luke Shumaker <lukeshu@xxxxxxxxxxx>
---
Documentation/git-fast-import.txt | 22 +++++++++++++---------
builtin/fast-export.c | 6 ++++++
builtin/fast-import.c | 10 ++++++++--
t/t9350-fast-export.sh | 11 ++++++++---
4 files changed, 35 insertions(+), 14 deletions(-)
diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt
index 39cfa05b28..8c1756bdad 100644
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@ -822,24 +822,28 @@ Creates an annotated tag referring to a specific commit. To create
lightweight (non-annotated) tags see the `reset` command below.
....
- 'tag' SP <name> LF
+ 'tag' SP <tagname> LF
mark?
+ ('refname' SP <refname> LF)?
'from' SP <commit-ish> LF
original-oid?
'tagger' (SP <name>)? SP LT <email> GT SP <when> LF
data
....
-where `<name>` is the name of the tag to create.
+where `<tagname>` is the name of the tag that is stored in the tag
+object itself. The value of `<tagname>` must be a valid for inclusion
+as part of a refname in Git and therefore may contain forward slashes.
+As `LF` is not valid in a Git refname, no quoting or escaping syntax
+is supported here.
-Tag names are automatically prefixed with `refs/tags/` when stored
-in Git, so importing the CVS branch symbol `RELENG-1_0-FINAL` would
-use just `RELENG-1_0-FINAL` for `<name>`, and fast-import will write the
-corresponding ref as `refs/tags/RELENG-1_0-FINAL`.
+The `refname` command controls where in the ref hierarchy to put the
+reference that points to the resulting tag object. If `refname` is
+not given, then `refs/tags/<tagname>` is used.
-The value of `<name>` must be a valid refname in Git and therefore
-may contain forward slashes. As `LF` is not valid in a Git refname,
-no quoting or escaping syntax is supported here.
+So, for example, importing the CVS branch symbol `RELENG-1_0-FINAL`
+would use just `RELENG-1_0-FINAL` for `<tagname>`, and fast-import
+will write the corresponding ref as `refs/tags/RELENG-1_0-FINAL`.
The `from` command is the same as in the `commit` command; see
above for details.
diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index 2bf83fe52e..de04aaf241 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -784,6 +784,7 @@ static void handle_tail(struct object_array *commits, struct rev_info *revs,
static void handle_tag(const char *refname, struct tag *tag)
{
+ static struct strbuf autorefname = STRBUF_INIT;
unsigned long size;
enum object_type type;
char *buf;
@@ -910,6 +911,9 @@ static void handle_tag(const char *refname, struct tag *tag)
}
}
+ strbuf_reset(&autorefname);
+ strbuf_addf(&autorefname, "refs/tags/%.*s", (int)tagname_len, tagname);
+
if (tagged->type == OBJ_TAG) {
printf("reset %s\nfrom %s\n\n",
refname, oid_to_hex(&null_oid));
@@ -919,6 +923,8 @@ static void handle_tag(const char *refname, struct tag *tag)
mark_next_object(&tag->object);
printf("mark :%"PRIu32"\n", last_idnum);
}
+ if (strcmp(refname, autorefname.buf))
+ printf("refname %s\n", refname);
if (tagged_mark)
printf("from :%d\n", tagged_mark);
else
diff --git a/builtin/fast-import.c b/builtin/fast-import.c
index 43287f929f..49e5a0c159 100644
--- a/builtin/fast-import.c
+++ b/builtin/fast-import.c
@@ -2794,9 +2794,15 @@ static void parse_new_tag(const char *arg)
read_next_command();
parse_mark();
+ /* refname ... */
strbuf_reset(&refname);
- strbuf_addstr(&refname, "refs/tags/");
- strbuf_addstr(&refname, tagname);
+ if (skip_prefix(command_buf.buf, "refname ", &v)) {
+ strbuf_addstr(&refname, v);
+ read_next_command();
+ } else {
+ strbuf_addstr(&refname, "refs/tags/");
+ strbuf_addstr(&refname, tagname);
+ }
/* from ... */
if (!skip_prefix(command_buf.buf, "from ", &from))
diff --git a/t/t9350-fast-export.sh b/t/t9350-fast-export.sh
index 0bcc1bd54e..089c0c0a24 100755
--- a/t/t9350-fast-export.sh
+++ b/t/t9350-fast-export.sh
@@ -34,6 +34,9 @@ test_expect_success 'setup' '
git commit -m sitzt file2 &&
test_tick &&
git tag -a -m valentin muss &&
+ git tag -a -m joseph pure &&
+ git update-ref refs/english-tags/rein refs/tags/pure &&
+ git update-ref -d refs/tags/pure &&
git merge -s ours main
'
@@ -42,6 +45,7 @@ test_expect_success 'fast-export | fast-import' '
MAIN=$(git rev-parse --verify main) &&
REIN=$(git rev-parse --verify rein) &&
+ PURE=$(git rev-parse --verify refs/english-tags/rein) &&
WER=$(git rev-parse --verify wer) &&
MUSS=$(git rev-parse --verify muss) &&
mkdir new &&
@@ -51,6 +55,7 @@ test_expect_success 'fast-export | fast-import' '
git fast-import &&
test $MAIN = $(git rev-parse --verify refs/heads/main) &&
test $REIN = $(git rev-parse --verify refs/tags/rein) &&
+ test $PURE = $(git rev-parse --verify refs/english-tags/rein) &&
test $WER = $(git rev-parse --verify refs/heads/wer) &&
test $MUSS = $(git rev-parse --verify refs/tags/muss)) <actual
@@ -359,7 +364,7 @@ test_expect_success 'fast-export | fast-import when main is tagged' '
git tag -m msg last &&
git fast-export -C -C --signed-tags=strip --all > output &&
- test $(grep -c "^tag " output) = 3
+ test $(grep -c "^tag " output) = 4
'
@@ -374,11 +379,11 @@ test_expect_success 'cope with tagger-less tags' '
TAG=$(git hash-object -t tag -w tag-content) &&
git update-ref refs/tags/sonnenschein $TAG &&
git fast-export -C -C --signed-tags=strip --all > output &&
- test $(grep -c "^tag " output) = 4 &&
+ test $(grep -c "^tag " output) = 5 &&
! grep "Unspecified Tagger" output &&
git fast-export -C -C --signed-tags=strip --all \
--fake-missing-tagger > output &&
- test $(grep -c "^tag " output) = 4 &&
+ test $(grep -c "^tag " output) = 5 &&
grep "Unspecified Tagger" output
'
--
2.31.1
