git@vger.kernel.org mailing list mirror (one of many)
 help / color / mirror / code / Atom feed
From: Junio C Hamano <gitster@pobox.com>
To: "Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>
Cc: git@jeffhostetler.com, git@vger.kernel.org, newren@gmail.com,
	pawelparuzel95@gmail.com, peff@peff.net,
	sandals@crustytoothpaste.net, tboegi@web.de,
	"SZEDER Gábor" <szeder.dev@gmail.com>
Subject: Re: [PATCH v4] clone: report duplicate entries on case-insensitive filesystems
Date: Mon, 13 Aug 2018 10:18:31 -0700	[thread overview]
Message-ID: <xmqq4lfy6v88.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <20180812090714.19060-1-pclouds@gmail.com> ("Nguyễn Thái Ngọc Duy"'s message of "Sun, 12 Aug 2018 11:07:14 +0200")

Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:

> Paths that only differ in case work fine in a case-sensitive
> filesystems, but if those repos are cloned in a case-insensitive one,
> you'll get problems. The first thing to notice is "git status" will
> never be clean with no indication what exactly is "dirty".
>
> This patch helps the situation a bit by pointing out the problem at
> clone time. Even though this patch talks about case sensitivity, the
> patch makes no assumption about folding rules by the filesystem. It
> simply observes that if an entry has been already checked out at clone
> time when we're about to write a new path, some folding rules are
> behind this.
>
> This patch is tested with vim-colorschemes repository on a JFS partition
> with case insensitive support on Linux. This repository has two files
> darkBlue.vim and darkblue.vim.
>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---
>  v4 removes nr_duplicates (and fixes that false warning Szeder
>  reported). It also hints about case insensitivity as a cause of
>  problem because it's most likely the case when this warning shows up.

Ah, you no longer have that counter and the pointer to the counter,
as you do not even report how many paths collide ;-)  Makes sense.

> diff --git a/entry.c b/entry.c
> index b5d1d3cf23..c70340df8e 100644
> --- a/entry.c
> +++ b/entry.c
> @@ -399,6 +399,31 @@ static int check_path(const char *path, int len, struct stat *st, int skiplen)
>  	return lstat(path, st);
>  }
>  
> +static void mark_colliding_entries(const struct checkout *state,
> +				   struct cache_entry *ce, struct stat *st)
> +{
> +	int i;
> +
> +	ce->ce_flags |= CE_MATCHED;
> +
> +#if !defined(GIT_WINDOWS_NATIVE) /* inode is always zero on Windows */
> +	for (i = 0; i < state->istate->cache_nr; i++) {
> +		struct cache_entry *dup = state->istate->cache[i];
> +
> +		if (dup == ce)
> +			break;
> +
> +		if (dup->ce_flags & (CE_MATCHED | CE_VALID | CE_SKIP_WORKTREE))
> +			continue;
> +
> +		if (dup->ce_stat_data.sd_ino == st->st_ino) {
> +			dup->ce_flags |= CE_MATCHED;
> +			break;
> +		}
> +	}
> +#endif
> +}

OK.  The whole loop might want to become a call to a helper function
whose implementation is platform dependent in the future, but that
should be kept outside the topic and left for a future enhancement.

> @@ -455,6 +480,9 @@ int checkout_entry(struct cache_entry *ce,
>  			return -1;
>  		}
>  
> +		if (state->clone)
> +			mark_colliding_entries(state, ce, &st);

OK.  I haven't carefully looked at the codepath but is it more
involved to instead *not* check out this ce (and leave the working
tree file that is already there for another path in the index
alone)?  I suspect it won't be as simple as

		if (state->clone) {
			mark_colliding_entries(state, ce, &st);
			return -1;
		}

but I think it would give much more pleasant end-user experience if
we can do so, especially on GIT_WINDOWS_NATIVE.  I would imagine
that the first thing those who see the message "foo.txt have
collided with something else we are not telling you" would want to
do is to see what "foo.txt" contains---and it may be obvious to
human that it contains the contents intended for "Foo.txt" instead,
if we somehow refrained from overwriting it here, which would
compensate for the lack of "this is the other path that collided
with your file."

It is perfectly an acceptable answer if it is "I looked at it, and
it is a lot more involved as there are these fallouts from the
codepaths that the control flows later from this point you haven't
checked and considered---let's keep overwriting, it is much safer."

> diff --git a/t/t5601-clone.sh b/t/t5601-clone.sh
> index 0b62037744..f2eb73bc74 100755
> --- a/t/t5601-clone.sh
> +++ b/t/t5601-clone.sh
> @@ -624,10 +624,16 @@ test_expect_success 'clone on case-insensitive fs' '
>  			git hash-object -w -t tree --stdin) &&
>  		c=$(git commit-tree -m bogus $t) &&
>  		git update-ref refs/heads/bogus $c &&
> -		git clone -b bogus . bogus
> +		git clone -b bogus . bogus 2>warning
>  	)
>  '
>  
> +test_expect_success !MINGW,!CYGWIN,CASE_INSENSITIVE_FS 'colliding file detection' '
> +	grep X icasefs/warning &&
> +	grep x icasefs/warning &&
> +	test_i18ngrep "the following paths have collided" icasefs/warning
> +'
> +

Ah, I was wondering why possible error message needs to be hidden in
the previous test---it is not hiding; it is capturing to look for
the paths in the message.  Makes sense.


  parent reply	other threads:[~2018-08-13 17:18 UTC|newest]

Thread overview: 96+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-27  9:59 Git clone and case sensitivity Paweł Paruzel
2018-07-27 20:59 ` brian m. carlson
2018-07-28  4:36   ` Duy Nguyen
2018-07-28  4:45     ` Duy Nguyen
2018-07-28  4:48       ` Jeff King
2018-07-28  5:11         ` Duy Nguyen
2018-07-28  9:48           ` Simon Ruderich
2018-07-28  9:56           ` Jeff King
2018-07-28 18:05             ` brian m. carlson
2018-07-29  5:26             ` Duy Nguyen
2018-07-29  9:28               ` Jeff King
2018-07-30 15:27                 ` [PATCH/RFC] clone: report duplicate entries on case-insensitive filesystems Nguyễn Thái Ngọc Duy
2018-07-31 18:23                   ` Torsten Bögershausen
2018-08-01 15:25                     ` Duy Nguyen
2018-07-31 18:44                   ` Elijah Newren
2018-07-31 19:12                     ` Junio C Hamano
2018-07-31 19:29                       ` Jeff King
2018-07-31 20:12                         ` Junio C Hamano
2018-07-31 20:37                           ` Jeff King
2018-07-31 20:57                             ` Junio C Hamano
2018-08-01 21:20                               ` Junio C Hamano
2018-08-02 14:43                                 ` Duy Nguyen
2018-08-02 16:27                                   ` Junio C Hamano
2018-08-02 19:06                                     ` Jeff King
2018-08-02 21:14                                       ` Junio C Hamano
2018-08-02 21:28                                         ` Jeff King
2018-08-03 18:23                                           ` Jeff Hostetler
2018-08-03 18:49                                             ` Junio C Hamano
2018-08-03 18:53                                             ` Jeff King
2018-08-05 14:01                                               ` Jeff Hostetler
2018-08-03 14:28                                   ` Torsten Bögershausen
2018-08-01 15:21                     ` Duy Nguyen
2018-07-31 19:13                   ` Junio C Hamano
2018-08-01 15:16                     ` Duy Nguyen
2018-08-07 19:01                   ` [PATCH v2] " Nguyễn Thái Ngọc Duy
2018-08-07 19:31                     ` Junio C Hamano
2018-08-08 19:48                       ` Jeff Hostetler
2018-08-08 22:31                         ` Jeff King
2018-08-09  0:41                           ` Junio C Hamano
2018-08-09 14:23                             ` Jeff King
2018-08-09 21:14                               ` Jeff Hostetler
2018-08-09 21:34                                 ` Jeff King
2018-08-09 21:40                                 ` Elijah Newren
2018-08-09 21:44                                   ` Jeff King
2018-08-09 21:53                                     ` Elijah Newren
2018-08-09 21:59                                       ` Jeff King
2018-08-09 23:05                                         ` Elijah Newren
2018-08-09 22:07                                   ` Junio C Hamano
2018-08-10 15:36                     ` [PATCH v3 0/1] clone: warn on colidding entries on checkout Nguyễn Thái Ngọc Duy
2018-08-10 15:36                       ` [PATCH v3 1/1] clone: report duplicate entries on case-insensitive filesystems Nguyễn Thái Ngọc Duy
2018-08-10 16:42                         ` Junio C Hamano
2018-08-11 10:09                         ` SZEDER Gábor
2018-08-11 13:16                           ` Duy Nguyen
2018-08-13 16:55                             ` Junio C Hamano
2018-08-13 17:12                               ` Duy Nguyen
2018-08-10 16:12                       ` [PATCH v3 0/1] clone: warn on colidding entries on checkout Junio C Hamano
2018-08-12  9:07                       ` [PATCH v4] clone: report duplicate entries on case-insensitive filesystems Nguyễn Thái Ngọc Duy
2018-08-13 15:32                         ` Jeff Hostetler
2018-08-13 17:18                         ` Junio C Hamano [this message]
2018-08-15 19:08                         ` Torsten Bögershausen
2018-08-15 19:35                           ` Duy Nguyen
2018-08-16 15:56                             ` [PATCH] config.txt: clarify core.checkStat = minimal Nguyễn Thái Ngọc Duy
2018-08-16 17:01                               ` Junio C Hamano
2018-08-16 18:19                                 ` Duy Nguyen
2018-08-16 22:29                                   ` Junio C Hamano
2018-08-17 15:26                                   ` Junio C Hamano
2018-08-17 15:29                                     ` Duy Nguyen
2018-08-15 19:38                           ` [PATCH v4] clone: report duplicate entries on case-insensitive filesystems Junio C Hamano
2018-08-16 14:03                             ` Torsten Bögershausen
2018-08-16 15:42                               ` Duy Nguyen
2018-08-16 16:23                               ` Junio C Hamano
2018-08-17 16:16                         ` [PATCH v5] " Nguyễn Thái Ngọc Duy
2018-08-17 17:20                           ` Junio C Hamano
2018-08-17 18:00                             ` Duy Nguyen
2018-08-17 19:46                           ` Torsten Bögershausen
2018-11-19  8:20                           ` Carlo Marcelo Arenas Belón
2018-11-19 12:28                             ` Torsten Bögershausen
2018-11-19 17:14                               ` Carlo Arenas
2018-11-19 18:24                                 ` Duy Nguyen
2018-11-19 21:03                                   ` Duy Nguyen
2018-11-19 21:04                                     ` Duy Nguyen
2018-11-19 21:17                                     ` Duy Nguyen
2018-11-19 23:29                                     ` Ramsay Jones
2018-11-19 23:54                                       ` Ramsay Jones
2018-11-20  1:05                                         ` Carlo Arenas
2018-11-20  2:22                                     ` Junio C Hamano
2018-11-20 16:28                                       ` [PATCH] clone: fix colliding file detection on APFS Nguyễn Thái Ngọc Duy
2018-11-20 19:20                                         ` Ramsay Jones
2018-11-20 19:35                                         ` Carlo Arenas
2018-11-20 19:38                                           ` Duy Nguyen
2018-11-22 17:59                                         ` [PATCH v1 1/1] t5601-99: Enable colliding file detection for MINGW tboegi
2018-11-22 20:16                                           ` Carlo Marcelo Arenas Belón
2018-11-23 11:24                                             ` Johannes Schindelin
2018-11-19 17:21                               ` [PATCH v5] clone: report duplicate entries on case-insensitive filesystems Ramsay Jones
2018-11-19 19:39                                 ` Carlo Arenas
2018-07-31 19:39                 ` Git clone and case sensitivity Jeff Hostetler

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=xmqq4lfy6v88.fsf@gitster-ct.c.googlers.com \
    --to=gitster@pobox.com \
    --cc=git@jeffhostetler.com \
    --cc=git@vger.kernel.org \
    --cc=newren@gmail.com \
    --cc=pawelparuzel95@gmail.com \
    --cc=pclouds@gmail.com \
    --cc=peff@peff.net \
    --cc=sandals@crustytoothpaste.net \
    --cc=szeder.dev@gmail.com \
    --cc=tboegi@web.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

	https://80x24.org/mirrors/git.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).