One of the tricks that `contrib/workdir/git-new-workdir` plays is to
making `packed-refs` in the new workdir a symlink to the `packed-refs`
file in the original repository. Before
42dfa7ecef ("commit_packed_refs(): use a staging file separate from
the lockfile", 2017-06-23), a lockfile was used as the staging file,
and because the `LOCK_NO_DEREF` was not used, the pointed-to file was
locked and modified.
But after that commit, the staging file was created using a tempfile,
with the end result that rewriting the `packed-refs` file in the
workdir overwrote the symlink rather than the original `packed-refs`
file.
Change `commit_packed_refs()` to use `get_locked_file_path()` to find
the path of the file that it should overwrite. Since that path was
properly resolved when the lockfile was created, this restores the
pre-42dfa7ecef behavior.
Also add a test case to document this use case and prevent a
regression like this from recurring.
Signed-off-by: Michael Haggerty <mhagger@xxxxxxxxxxxx>
---
Sorry for the slow response; I've been traveling and very busy.
I didn't even know that a symlinked `packed-refs` file is a thing. The
attached patch should fix the problem. It applies on top of v3 of
mh/packed-ref-store [1] (which is already in next).
Michael
[1] http://public-inbox.org/git/cover.1498933362.git.mhagger@xxxxxxxxxxxx/
refs/packed-backend.c | 24 ++++++++++++++++++------
t/t3210-pack-refs.sh | 15 +++++++++++++++
2 files changed, 33 insertions(+), 6 deletions(-)
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index a28befbfa3..59e7d1a509 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -610,19 +610,27 @@ int commit_packed_refs(struct ref_store *ref_store, struct strbuf *err)
struct packed_ref_cache *packed_ref_cache =
get_packed_ref_cache(refs);
int ok;
+ int ret = -1;
struct strbuf sb = STRBUF_INIT;
FILE *out;
struct ref_iterator *iter;
+ char *packed_refs_path;
if (!is_lock_file_locked(&refs->lock))
die("BUG: commit_packed_refs() called when unlocked");
- strbuf_addf(&sb, "%s.new", refs->path);
+ /*
+ * If packed-refs is a symlink, we want to overwrite the
+ * symlinked-to file, not the symlink itself. Also, put the
+ * staging file next to it:
+ */
+ packed_refs_path = get_locked_file_path(&refs->lock);
+ strbuf_addf(&sb, "%s.new", packed_refs_path);
if (create_tempfile(&refs->tempfile, sb.buf) < 0) {
strbuf_addf(err, "unable to create file %s: %s",
sb.buf, strerror(errno));
strbuf_release(&sb);
- return -1;
+ goto out;
}
strbuf_release(&sb);
@@ -660,17 +668,21 @@ int commit_packed_refs(struct ref_store *ref_store, struct strbuf *err)
goto error;
}
- if (rename_tempfile(&refs->tempfile, refs->path)) {
+ if (rename_tempfile(&refs->tempfile, packed_refs_path)) {
strbuf_addf(err, "error replacing %s: %s",
refs->path, strerror(errno));
- return -1;
+ goto out;
}
- return 0;
+ ret = 0;
+ goto out;
error:
delete_tempfile(&refs->tempfile);
- return -1;
+
+out:
+ free(packed_refs_path);
+ return ret;
}
/*
diff --git a/t/t3210-pack-refs.sh b/t/t3210-pack-refs.sh
index 2bb4b25ed9..0d8a03e2a9 100755
--- a/t/t3210-pack-refs.sh
+++ b/t/t3210-pack-refs.sh
@@ -238,4 +238,19 @@ test_expect_success 'retry acquiring packed-refs.lock' '
git -c core.packedrefstimeout=3000 pack-refs --all --prune
'
+test_expect_success 'pack symlinked packed-refs' '
+ # First make sure that symlinking works when reading:
+ git update-ref refs/heads/loosy refs/heads/master &&
+ git for-each-ref >all-refs-before &&
+ mv .git/packed-refs .git/my-deviant-packed-refs &&
+ ln -s my-deviant-packed-refs .git/packed-refs &&
+ git for-each-ref >all-refs-linked &&
+ test_cmp all-refs-before all-refs-linked &&
+ git pack-refs --all --prune &&
+ git for-each-ref >all-refs-packed &&
+ test_cmp all-refs-before all-refs-packed &&
+ test -h .git/packed-refs &&
+ test "$(readlink .git/packed-refs)" = "my-deviant-packed-refs"
+'
+
test_done
--
2.11.0
