Hi Elijah,
On Mon, Sep 30, 2019 at 12:11:06PM -0700, Elijah Newren wrote:
> Commits 404ebceda01c ("dir: also check directories for matching
> pathspecs", 2019-09-17) and 89a1f4aaf765 ("dir: if our pathspec might
> match files under a dir, recurse into it", 2019-09-17) added calls to
> match_pathspec() and do_match_pathspec() passing along their pathspec
> parameter. Both match_pathspec() and do_match_pathspec() assume the
> pathspec argument they are given is non-NULL. It turns out that
> unpack-tree.c's verify_clean_subdirectory() calls read_directory() with
> pathspec == NULL, and it is possible on case insensitive filesystems for
> that NULL to make it to these new calls to match_pathspec() and
> do_match_pathspec(). Add appropriate checks on the NULLness of pathspec
> to avoid a segfault.
>
> In case the negation throws anyone off (one of the calls was to
> do_match_pathspec() while the other was to !match_pathspec(), yet no
> negation of the NULLness of pathspec is used), there are two ways to
> understand the differences:
> * The code already handled the pathspec == NULL cases before this
> series, and this series only tried to change behavior when there was
> a pathspec, thus we only want to go into the if-block if pathspec is
> non-NULL.
> * One of the calls is for whether to recurse into a subdirectory, the
> other is for after we've recursed into it for whether we want to
> remove the subdirectory itself (i.e. the subdirectory didn't match
> but something under it could have). That difference in situation
> leads to the slight differences in logic used (well, that and the
> slightly unusual fact that we don't want empty pathspecs to remove
> untracked directories by default).
>
> Helped-by: Denton Liu <liu.denton@xxxxxxxxx>
> Helped-by: SZEDER Gábor <szeder.dev@xxxxxxxxx>
> Signed-off-by: Elijah Newren <newren@xxxxxxxxx>
> ---
> This patch applies on top of en/clean-nested-with-ignored, which is now
> in next.
>
> Denton found and analyzed one issue and provided the patch for the
> match_pathspec() call, SZEDER figured out why the issue only reproduced
> for some folks and not others and provided the testcase, and I looked
> through the remainder of the series and noted the do_match_pathspec()
> call that should have the same check.
Thanks for catching what I missed.
>
> So, I'm not sure who should be author and who should be helped-by; I
> feel like their contributions are possibly bigger than mine. While I
> tried to reproduce and debug, they ended up doing the work, and I just
> looked through the rest of the series for similar issues and wrote up
> a commit message. *shrug*
Eh, it doesn't really matter to me. GitHub appears to have de facto
standardised the Co-authored-by: trailer to allow credit to be split
amonst multiple authors so _maybe_ we could use that, but I'm pretty
impartial.
>
> dir.c | 8 +++++---
> t/t0050-filesystem.sh | 23 +++++++++++++++++++++++
> 2 files changed, 28 insertions(+), 3 deletions(-)
>
> diff --git a/dir.c b/dir.c
> index 7ff79170fc..bd39b86be4 100644
> --- a/dir.c
> +++ b/dir.c
> @@ -1962,8 +1962,9 @@ static enum path_treatment read_directory_recursive(struct dir_struct *dir,
> ((state == path_untracked) &&
> (get_dtype(cdir.de, istate, path.buf, path.len) == DT_DIR) &&
> ((dir->flags & DIR_SHOW_IGNORED_TOO) ||
> - do_match_pathspec(istate, pathspec, path.buf, path.len,
> - baselen, NULL, DO_MATCH_LEADING_PATHSPEC) == MATCHED_RECURSIVELY_LEADING_PATHSPEC))) {
> + (pathspec &&
> + do_match_pathspec(istate, pathspec, path.buf, path.len,
> + baselen, NULL, DO_MATCH_LEADING_PATHSPEC) == MATCHED_RECURSIVELY_LEADING_PATHSPEC)))) {
> struct untracked_cache_dir *ud;
> ud = lookup_untracked(dir->untracked, untracked,
> path.buf + baselen,
> @@ -1975,7 +1976,8 @@ static enum path_treatment read_directory_recursive(struct dir_struct *dir,
> if (subdir_state > dir_state)
> dir_state = subdir_state;
>
> - if (!match_pathspec(istate, pathspec, path.buf, path.len,
> + if (pathspec &&
> + !match_pathspec(istate, pathspec, path.buf, path.len,
> 0 /* prefix */, NULL,
> 0 /* do NOT special case dirs */))
> state = path_none;
> diff --git a/t/t0050-filesystem.sh b/t/t0050-filesystem.sh
> index 192c94eccd..edb30f9eb2 100755
> --- a/t/t0050-filesystem.sh
> +++ b/t/t0050-filesystem.sh
> @@ -131,4 +131,27 @@ $test_unicode 'merge (silent unicode normalization)' '
> git merge topic
> '
>
> +test_expect_success CASE_INSENSITIVE_FS 'checkout with no pathspec and a case insensitive fs' '
> + git init repo &&
> + (
> + cd repo &&
> +
> + >Gitweb &&
> + git add Gitweb &&
> + git commit -m "add Gitweb" &&
> +
> + git checkout --orphan todo &&
> + git reset --hard &&
> + # the subdir is crucial, without it there is no segfault
We should either remove this comment or change the justification. A
future reader may be confused at what particular segfault this refers
to.
> + mkdir -p gitweb/subdir &&
> + >gitweb/subdir/file &&
> + # it is not strictly necessary to add and commit the
> + # gitweb directory, its presence is sufficient
Same here, its presence is sufficient to... what?
Thanks,
Denton
> + git add gitweb &&
> + git commit -m "add gitweb/subdir/file" &&
> +
> + git checkout master
> + )
> +'
> +
> test_done
> --
> 2.22.1.14.g885c22d24b
>
