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From: Jeff King <peff@peff.net>
To: Derrick Stolee <stolee@gmail.com>
Cc: Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org, me@ttaylorr.com, newren@gmail.com,
	Derrick Stolee <dstolee@microsoft.com>
Subject: Re: [PATCH 8/8] sparse-checkout: write escaped patterns in cone mode
Date: Fri, 24 Jan 2020 16:42:06 -0500	[thread overview]
Message-ID: <20200124214206.GA2211026@coredump.intra.peff.net> (raw)
In-Reply-To: <d4fe0b4a-9e3f-6669-9068-d7b4b8934d1b@gmail.com>

On Fri, Jan 24, 2020 at 04:10:21PM -0500, Derrick Stolee wrote:

> Hm. Perhaps you are right! The ls-tree output for the test example
> is:
> 
> 	deep
> 	folder1
> 	folder2
> 	"zbad\\dir"
> 	zdoes*exist
> 
> so the "zdoes*exist" value is not escaped. I believe the current
> logic does something extra: consider supplying this input to
> 'git sparse-checkout set --stdin':
> 
> 	deep
> 	folder1
> 	folder2
> 	"zbad\\dir"
> 	zdoes\*exist
> 
> then should we un-escape "\*" to "*"? Or is this not a valid input
> because a backslash should have been quoted into C-style quotes?

I'd think we should not un-escape anything, because we weren't told that
this was a C-style quoted string by the presence of an opening
double-quote. And that's how, say, update-index behaves:

  $ blob=$(echo foo | git hash-object -w --stdin)
  $ printf '100644 %s\t%s\n' \
      $blob 'just*asterisk' \
      $blob 'backslash\without\quotes' \
      $blob '"backslash\\with\\quotes"' |
    git update-index --index-info

which results in:

  $ git ls-files
  "backslash\\with\\quotes"
  "backslash\\without\\quotes"
  just*asterisk

  [same, but without quoting]
  $ git ls-files -z | tr '\0' '\n'
  backslash\with\quotes
  backslash\without\quotes
  just*asterisk

> The behavior in the current series allows this output that would
> never be written by "git ls-tree".

Yes, I think we'd never write that, because ls-tree would quote anything
with a backslash in it, even though it's not strictly necessary. But it
would be valid input to specify a file that has backslashes but not
double-quotes, and I think sparse-checkout should be changed to match
update-index here.

> I was playing around with this, and I think that quote_c_style() is
> necessary for the output, but we have a strange in-memory situation
> for the other escaping: we both fill the hashsets with the un-escaped
> data and fill the pattern list with the escaped patterns.

Yeah, but I think that the syntactic escaping on input might not have
identical rules to the escaping needed for the patterns.

So it makes sense to me to handle input as a separate mechanism, get a
pristine copy of what the user was trying to communicate to us, and then
re-escape whatever we need to put into the pattern list.

And ultimately the flow would be something like:

  - read input
    - if argument is from command-line, use it verbatim
    - else if reading stdin with "-z", use it verbatim
    - else if line starts with double-quote, unquote_c_style()
    - else use line verbatim
    - the result is a single pristine filename
  - fill hashset with pristine filenames
  - generate pattern list to write to sparse file, escaping filenames as
    necessary according to sparse-pattern rules

Obviously you don't have a "-z" yet, but I think it's something we'd
probably want in the long run. And anything coming from the command-line
shouldn't need quoting to get it to us either (and so we'd need to
escape before writing to the sparse file).

-Peff

  reply	other threads:[~2020-01-24 21:42 UTC|newest]

Thread overview: 82+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-14 19:25 [PATCH 0/8] Harden the sparse-checkout builtin Derrick Stolee via GitGitGadget
2020-01-14 19:25 ` [PATCH 1/8] t1091: use check_files to reduce boilerplate Derrick Stolee via GitGitGadget
2020-01-16 21:40   ` Junio C Hamano
2020-01-14 19:25 ` [PATCH 2/8] sparse-checkout: create leading directories Derrick Stolee via GitGitGadget
2020-01-16 21:46   ` Junio C Hamano
2020-01-14 19:25 ` [PATCH 3/8] clone: fix --sparse option with URLs Derrick Stolee via GitGitGadget
2020-01-14 19:30   ` Taylor Blau
2020-01-14 19:25 ` [PATCH 4/8] sparse-checkout: cone mode does not recognize "**" Derrick Stolee via GitGitGadget
2020-01-14 21:16   ` Jeff King
2020-01-14 19:25 ` [PATCH 5/8] sparse-checkout: detect short patterns Derrick Stolee via GitGitGadget
2020-01-14 19:26 ` [PATCH 6/8] sparse-checkout: warn on incorrect '*' in patterns Derrick Stolee via GitGitGadget
2020-01-14 19:26 ` [PATCH 7/8] sparse-checkout: properly match escaped characters Derrick Stolee via GitGitGadget
2020-01-14 21:21   ` Jeff King
2020-01-14 22:08     ` Derrick Stolee
2020-01-14 19:26 ` [PATCH 8/8] sparse-checkout: write escaped patterns in cone mode Derrick Stolee via GitGitGadget
2020-01-14 21:25   ` Jeff King
2020-01-14 22:11     ` Derrick Stolee
2020-01-14 22:48       ` Jeff King
2020-01-24 21:10         ` Derrick Stolee
2020-01-24 21:42           ` Jeff King [this message]
2020-01-28 15:03             ` Derrick Stolee
2020-01-14 19:34 ` [PATCH 0/8] Harden the sparse-checkout builtin Taylor Blau
2020-01-14 19:44   ` Derrick Stolee
2020-01-14 21:31     ` Jeff King
2020-01-15 19:16 ` Junio C Hamano
2020-01-15 20:32   ` Derrick Stolee
2020-01-24 21:19 ` [PATCH v2 00/12] " Derrick Stolee via GitGitGadget
2020-01-24 21:19   ` [PATCH v2 01/12] t1091: use check_files to reduce boilerplate Derrick Stolee via GitGitGadget
2020-01-24 21:19   ` [PATCH v2 02/12] t1091: improve here-docs Derrick Stolee via GitGitGadget
2020-01-24 21:19   ` [PATCH v2 03/12] sparse-checkout: create leading directories Derrick Stolee via GitGitGadget
2020-01-24 21:19   ` [PATCH v2 04/12] clone: fix --sparse option with URLs Derrick Stolee via GitGitGadget
2020-01-24 21:19   ` [PATCH v2 05/12] sparse-checkout: fix documentation typo for core.sparseCheckoutCone Jeff King via GitGitGadget
2020-01-24 21:19   ` [PATCH v2 06/12] sparse-checkout: cone mode does not recognize "**" Derrick Stolee via GitGitGadget
2020-01-24 21:19   ` [PATCH v2 07/12] sparse-checkout: detect short patterns Derrick Stolee via GitGitGadget
2020-01-24 21:19   ` [PATCH v2 08/12] sparse-checkout: warn on incorrect '*' in patterns Derrick Stolee via GitGitGadget
2020-01-24 21:19   ` [PATCH v2 09/12] sparse-checkout: properly match escaped characters Derrick Stolee via GitGitGadget
2020-01-24 21:19   ` [PATCH v2 10/12] sparse-checkout: write escaped patterns in cone mode Derrick Stolee via GitGitGadget
2020-01-24 21:19   ` [PATCH v2 11/12] sparse-checkout: use C-style quotes in 'list' subcommand Derrick Stolee via GitGitGadget
2020-01-24 21:19   ` [PATCH v2 12/12] sparse-checkout: improve docs around 'set' in cone mode Derrick Stolee via GitGitGadget
2020-01-28 18:26   ` [PATCH v3 00/12] Harden the sparse-checkout builtin Derrick Stolee via GitGitGadget
2020-01-28 18:26     ` [PATCH v3 01/12] t1091: use check_files to reduce boilerplate Derrick Stolee via GitGitGadget
2020-01-28 18:26     ` [PATCH v3 02/12] t1091: improve here-docs Derrick Stolee via GitGitGadget
2020-01-28 18:26     ` [PATCH v3 03/12] sparse-checkout: create leading directories Derrick Stolee via GitGitGadget
2020-01-28 18:26     ` [PATCH v3 04/12] clone: fix --sparse option with URLs Derrick Stolee via GitGitGadget
2020-01-28 18:26     ` [PATCH v3 05/12] sparse-checkout: fix documentation typo for core.sparseCheckoutCone Jeff King via GitGitGadget
2020-01-28 18:26     ` [PATCH v3 06/12] sparse-checkout: cone mode does not recognize "**" Derrick Stolee via GitGitGadget
2020-01-28 18:26     ` [PATCH v3 07/12] sparse-checkout: detect short patterns Derrick Stolee via GitGitGadget
2020-01-28 18:26     ` [PATCH v3 08/12] sparse-checkout: warn on incorrect '*' in patterns Derrick Stolee via GitGitGadget
2020-01-28 18:26     ` [PATCH v3 09/12] sparse-checkout: properly match escaped characters Derrick Stolee via GitGitGadget
2020-01-29 10:03       ` Jeff King
2020-01-29 13:58         ` Derrick Stolee
2020-01-29 14:04           ` Derrick Stolee
2020-01-28 18:26     ` [PATCH v3 10/12] sparse-checkout: write escaped patterns in cone mode Derrick Stolee via GitGitGadget
2020-01-29 10:17       ` Jeff King
2020-01-29 10:33         ` Jeff King
2020-01-29 14:16           ` Derrick Stolee
2020-01-29 14:39             ` Derrick Stolee
2020-01-30  7:29             ` Jeff King
2020-01-30 15:01               ` Derrick Stolee
2020-01-28 18:26     ` [PATCH v3 11/12] sparse-checkout: use C-style quotes in 'list' subcommand Derrick Stolee via GitGitGadget
2020-01-29 10:23       ` Jeff King
2020-01-28 18:26     ` [PATCH v3 12/12] sparse-checkout: improve docs around 'set' in cone mode Derrick Stolee via GitGitGadget
2020-01-31 20:16     ` [PATCH v4 00/15] Harden the sparse-checkout builtin Derrick Stolee via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 01/15] t1091: use check_files to reduce boilerplate Derrick Stolee via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 02/15] t1091: improve here-docs Derrick Stolee via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 03/15] sparse-checkout: create leading directories Derrick Stolee via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 04/15] clone: fix --sparse option with URLs Derrick Stolee via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 05/15] sparse-checkout: fix documentation typo for core.sparseCheckoutCone Jeff King via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 06/15] sparse-checkout: cone mode does not recognize "**" Derrick Stolee via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 07/15] sparse-checkout: detect short patterns Derrick Stolee via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 08/15] sparse-checkout: warn on globs in cone patterns Derrick Stolee via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 09/15] sparse-checkout: properly match escaped characters Derrick Stolee via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 10/15] sparse-checkout: write escaped patterns in cone mode Derrick Stolee via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 11/15] sparse-checkout: unquote C-style strings over --stdin Derrick Stolee via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 12/15] sparse-checkout: use C-style quotes in 'list' subcommand Derrick Stolee via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 13/15] sparse-checkout: escape all glob characters on write Derrick Stolee via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 14/15] sparse-checkout: improve docs around 'set' in cone mode Derrick Stolee via GitGitGadget
2020-01-31 20:16       ` [PATCH v4 15/15] sparse-checkout: fix cone mode behavior mismatch Derrick Stolee via GitGitGadget
2020-01-31 20:36       ` [PATCH v4 00/15] Harden the sparse-checkout builtin Elijah Newren
2020-02-03 14:09         ` Derrick Stolee
2020-02-08 23:32           ` Taylor Blau
2020-02-09 17:27             ` Junio C Hamano

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