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From: Elijah Newren <newren@gmail.com>
To: Denton Liu <liu.denton@gmail.com>
Cc: "Junio C Hamano" <gitster@pobox.com>,
	"Git Mailing List" <git@vger.kernel.org>,
	"SZEDER Gábor" <szeder.dev@gmail.com>
Subject: Re: [PATCH] dir: special case check for the possibility that pathspec is NULL
Date: Tue, 1 Oct 2019 00:01:44 -0700
Message-ID: <CABPp-BGv0zRbvSkXSvF=Q55Z9gJ1od4dsDpTOSDLVv9tppkKnw@mail.gmail.com> (raw)
In-Reply-To: <20190930223105.GA86525@generichostname>

On Mon, Sep 30, 2019 at 3:31 PM Denton Liu <liu.denton@gmail.com> wrote:
>
> 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@gmail.com>
> > Helped-by: SZEDER Gábor <szeder.dev@gmail.com>
> > Signed-off-by: Elijah Newren <newren@gmail.com>
> > ---
> > 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.

Yep, good point, I'll just go ahead and remove it.

> > +             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?

I will clean this one too and send a v2 tomorrow; it's getting late.

Thanks for all the digging you did on this bug to get it sorted out,
Denton; I really appreciate it.

Elijah

  reply index

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-25 18:59 [PATCH] t7300-clean: demonstrate deleting nested repo with an ignored file breakage SZEDER Gábor
2019-08-25 20:34 ` SZEDER Gábor
2019-08-25 22:32 ` Philip Oakley
2019-08-26  7:48   ` SZEDER Gábor
2019-09-05 15:47 ` [RFC PATCH v2 00/12] Fix some git clean issues Elijah Newren
2019-09-05 15:47   ` [RFC PATCH v2 01/12] t7300: Add some testcases showing failure to clean specified pathspecs Elijah Newren
2019-09-05 15:47   ` [RFC PATCH v2 02/12] dir: fix typo in comment Elijah Newren
2019-09-05 15:47   ` [RFC PATCH v2 03/12] dir: fix off-by-one error in match_pathspec_item Elijah Newren
2019-09-05 15:47   ` [RFC PATCH v2 04/12] dir: Directories should be checked for matching pathspecs too Elijah Newren
2019-09-05 15:47   ` [RFC PATCH v2 05/12] dir: Make the DO_MATCH_SUBMODULE code reusable for a non-submodule case Elijah Newren
2019-09-05 15:47   ` [RFC PATCH v2 06/12] dir: If our pathspec might match files under a dir, recurse into it Elijah Newren
2019-09-05 15:47   ` [RFC PATCH v2 07/12] dir: add commentary explaining match_pathspec_item's return value Elijah Newren
2019-09-05 15:47   ` [RFC PATCH v2 08/12] git-clean.txt: do not claim we will delete files with -n/--dry-run Elijah Newren
2019-09-05 15:47   ` [RFC PATCH v2 09/12] clean: disambiguate the definition of -d Elijah Newren
2019-09-05 15:47   ` [RFC PATCH v2 10/12] clean: avoid removing untracked files in a nested git repository Elijah Newren
2019-09-05 21:20     ` SZEDER Gábor
2019-09-05 15:47   ` [RFC PATCH v2 11/12] clean: rewrap overly long line Elijah Newren
2019-09-05 15:47   ` [RFC PATCH v2 12/12] clean: fix theoretical path corruption Elijah Newren
2019-09-05 19:27     ` SZEDER Gábor
2019-09-07  0:34       ` Elijah Newren
2019-09-05 19:01   ` [RFC PATCH v2 00/12] Fix some git clean issues SZEDER Gábor
2019-09-07  0:33     ` Elijah Newren
2019-09-12 22:12   ` [PATCH v3 " Elijah Newren
2019-09-12 22:12     ` [PATCH v3 01/12] t7300: add testcases showing failure to clean specified pathspecs Elijah Newren
2019-09-13 18:54       ` Junio C Hamano
2019-09-13 19:10         ` Elijah Newren
2019-09-13 20:29           ` Junio C Hamano
2019-09-12 22:12     ` [PATCH v3 02/12] dir: fix typo in comment Elijah Newren
2019-09-12 22:12     ` [PATCH v3 03/12] dir: fix off-by-one error in match_pathspec_item Elijah Newren
2019-09-13 19:05       ` Junio C Hamano
2019-09-12 22:12     ` [PATCH v3 04/12] dir: also check directories for matching pathspecs Elijah Newren
2019-09-12 22:12     ` [PATCH v3 05/12] dir: make the DO_MATCH_SUBMODULE code reusable for a non-submodule case Elijah Newren
2019-09-12 22:12     ` [PATCH v3 06/12] dir: if our pathspec might match files under a dir, recurse into it Elijah Newren
2019-09-13 19:45       ` Junio C Hamano
2019-09-12 22:12     ` [PATCH v3 07/12] dir: add commentary explaining match_pathspec_item's return value Elijah Newren
2019-09-13 20:04       ` Junio C Hamano
2019-09-12 22:12     ` [PATCH v3 08/12] git-clean.txt: do not claim we will delete files with -n/--dry-run Elijah Newren
2019-09-12 22:12     ` [PATCH v3 09/12] clean: disambiguate the definition of -d Elijah Newren
2019-09-12 22:12     ` [PATCH v3 10/12] clean: avoid removing untracked files in a nested git repository Elijah Newren
2019-09-12 22:12     ` [PATCH v3 11/12] clean: rewrap overly long line Elijah Newren
2019-09-12 22:12     ` [PATCH v3 12/12] clean: fix theoretical path corruption Elijah Newren
2019-09-17 16:34     ` [PATCH v4 00/12] Fix some git clean issues Elijah Newren
2019-09-17 16:34       ` [PATCH v4 01/12] t7300: add testcases showing failure to clean specified pathspecs Elijah Newren
2019-09-17 16:34       ` [PATCH v4 02/12] dir: fix typo in comment Elijah Newren
2019-09-17 16:34       ` [PATCH v4 03/12] dir: fix off-by-one error in match_pathspec_item Elijah Newren
2019-09-17 16:34       ` [PATCH v4 04/12] dir: also check directories for matching pathspecs Elijah Newren
2019-09-25 20:39         ` [BUG] git is segfaulting, was " Denton Liu
2019-09-25 21:28           ` Elijah Newren
2019-09-25 21:55             ` Denton Liu
2019-09-26 20:35               ` Denton Liu
2019-09-27  0:12                 ` Elijah Newren
2019-09-27  1:09           ` SZEDER Gábor
2019-09-27  2:17             ` SZEDER Gábor
2019-09-27 17:10               ` Denton Liu
2019-09-30 19:11                 ` [PATCH] dir: special case check for the possibility that pathspec is NULL Elijah Newren
2019-09-30 22:31                   ` Denton Liu
2019-10-01  7:01                     ` Elijah Newren [this message]
2019-10-01 18:30                   ` [PATCH v2] " Elijah Newren
2019-10-01 18:40                     ` Denton Liu
2019-10-01 18:54                       ` Elijah Newren
2019-10-01 18:55                       ` [PATCH v3] " Elijah Newren
2019-10-01 19:35                         ` Denton Liu
2019-10-01 19:39                           ` Elijah Newren
2019-10-02 15:51                             ` Elijah Newren
2019-10-07 18:04                         ` SZEDER Gábor
2019-09-17 16:34       ` [PATCH v4 05/12] dir: make the DO_MATCH_SUBMODULE code reusable for a non-submodule case Elijah Newren
2019-09-17 16:34       ` [PATCH v4 06/12] dir: if our pathspec might match files under a dir, recurse into it Elijah Newren
2019-09-17 16:34       ` [PATCH v4 07/12] dir: add commentary explaining match_pathspec_item's return value Elijah Newren
2019-09-17 16:35       ` [PATCH v4 08/12] git-clean.txt: do not claim we will delete files with -n/--dry-run Elijah Newren
2019-09-17 16:35       ` [PATCH v4 09/12] clean: disambiguate the definition of -d Elijah Newren
2019-09-17 16:35       ` [PATCH v4 10/12] clean: avoid removing untracked files in a nested git repository Elijah Newren
2019-09-17 16:35       ` [PATCH v4 11/12] clean: rewrap overly long line Elijah Newren
2019-09-17 16:35       ` [PATCH v4 12/12] clean: fix theoretical path corruption Elijah Newren

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