On Sun, Sep 02, 2018 at 12:17:53AM +0200, Ævar Arnfjörð Bjarmason wrote:
> > Here are the steps to reproduce it:
> > $ git clone git://github.com/lucvoo/sparse-dev.git <somedir>
> > $ cd <somedir>
> > $ git co index-corruption
> > $ git rm -r validation/ Documentation/
> > $ git commit -m <some message> -p
> > $ git status
> > error: index uses $?+? extension, which we do not understand
> > fatal: index file corrupt
> >
> > The 'extension' pattern '$?+?', can vary a bit, sometimes
> > it's just '????', but always seems 4 chars.
> > If the commit command doesn't use the '-p' flag, there is no
> > problem. The repository itself is not corrupted, it's only
> > the index. It happends with git 2.18.0 and 2.17.0
>
> Yeah this is a bug, I didn't dig much but testing with this script down
> to 2.8.0:
> [...]
> I found that the first bad commit was: 680ee550d7 ("commit: skip
> discarding the index if there is no pre-commit hook", 2017-08-14)
I think it's much older than that. I set up my test repo like this:
git clone git://github.com/lucvoo/sparse-dev.git
cd sparse-dev
git checkout --detach
and then bisected with this script:
cd /path/to/sparse-dev
rm .git/index
git reset --hard index-corruption &&
git rm -q -r validation/ Documentation/ &&
git commit -qm foo -p &&
git status
Since a33fc72fe9 (read-cache: force_verify_index_checksum, 2017-04-14),
that produces the corrupt extension error. But before that, I
consistently get:
error: bad index file sha1 signature
fatal: index file corrupt
from git-commit. And that bisects back to 9c4d6c0297 (cache-tree: Write
updated cache-tree after commit, 2014-07-13).
If I revert that commit (which takes some untangling, see below), then
the problem seems to go away. Here's the patch I tried on top of the
current master, though I think it is actually the first hunk that is
making the difference.
---
diff --git a/builtin/commit.c b/builtin/commit.c
index 0d9828e29e..779c5e2cb5 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -359,13 +359,6 @@ static const char *prepare_index(int argc, const char **argv, const char *prefix
discard_cache();
read_cache_from(get_lock_file_path(&index_lock));
- if (update_main_cache_tree(WRITE_TREE_SILENT) == 0) {
- if (reopen_lock_file(&index_lock) < 0)
- die(_("unable to write index file"));
- if (write_locked_index(&the_index, &index_lock, 0))
- die(_("unable to update temporary index"));
- } else
- warning(_("Failed to update main cache tree"));
commit_style = COMMIT_NORMAL;
ret = get_lock_file_path(&index_lock);
@@ -408,9 +401,6 @@ static const char *prepare_index(int argc, const char **argv, const char *prefix
if (!only && !pathspec.nr) {
hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);
refresh_cache_or_die(refresh_flags);
- if (active_cache_changed
- || !cache_tree_fully_valid(active_cache_tree))
- update_main_cache_tree(WRITE_TREE_SILENT);
if (write_locked_index(&the_index, &index_lock,
COMMIT_LOCK | SKIP_IF_UNCHANGED))
die(_("unable to write new_index file"));
@@ -457,7 +447,6 @@ static const char *prepare_index(int argc, const char **argv, const char *prefix
hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);
add_remove_files(&partial);
refresh_cache(REFRESH_QUIET);
- update_main_cache_tree(WRITE_TREE_SILENT);
if (write_locked_index(&the_index, &index_lock, 0))
die(_("unable to write new_index file"));
-Peff
