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 <mhag...@alum.mit.edu> --- 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.mhag...@alum.mit.edu/ 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
