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Re: [PATCH v5 1/3] builtin/grep.c: add --sparse option

From
Elijah Newren <newren@gmail.com>
Date
Sep 14, 2022, 06:08 UTC
Message-ID
<CABPp-BF-z72=hY_Jf8h3g95s+wwZOsV_S=+dDNs_AVskQxoaTw@mail.gmail.com>
In-Reply-To
<20220908001854.206789-2-shaoxuan.yuan02@gmail.com>
Hi Shaoxuan,

Please note that it's customary to cc folks who have commented on previous versions of your patch series when you re-roll.

On Wed, Sep 7, 2022 at 5:28 PM Shaoxuan Yuan <shaoxuan.yuan02@gmail.com> wrote:
>
> Add a --sparse option to `git-grep`.

It's awesome you're working on this. Adding more of "behavior A" (restricting querying commands to the sparse cone) is something I've wanted for a long time.

I think most of your code is beneficial, but I do have some issues with high level direction you were implementing, which may require some tweaks...

Show 5 quoted lines
> When the '--cached' option is used with the 'git grep' command, the
> search is limited to the blobs found in the index, not in the worktree.
> If the user has enabled sparse-checkout, this might present more results
> than they would like, since the files outside of the sparse-checkout are
> unlikely to be important to them.

"files outside of the sparse-checkout are unlikely to be important to [users]" is certainly an issue. But it's *much* wider than this. Beyond `grep --cached`, it also affects `grep REVISION`, `log`, `diff [REVISION]`, and related things...perhaps even something like `blame`. I think all those other commands probably deserve a mode where they restrict output to the view associated with the user's cone. I've brought that up before[1]. I was skeptical of making it the default, because it'd probably take a long time to implement it everywhere. Slowly changing defaults of all commands over many git releases seems like a poor strategy, but I'm afraid that's what it looks like we are doing here.

I'm also worried that slowly changing the defaults without a high-level plan will lead to users struggling to figure out what flag(s) to pass. Are we going to be stuck in a situation where users have to remember that for a dense search, they use one flag for `grep --cached`, a different one for `grep [REVISION]`, no flag is needed for `diff [REVISION]`, but yet a different flag is needed for `git log`?

I'm also curious whether there shouldn't be a config option for something like this, so folks don't have to specify it with every invocation. In particular, while I certainly have users that want to just query git for information about the part of the history they are interested in, there are other users who are fully aware they are working in a bigger repository and want to search for additional things to add to their sparse-checkout and predominantly use grep for things like that. They have even documented that `git grep --cached <TERM>` can be used in sparse-checkouts for this purpose...and have been using that for a few years. (I did warn them at the time that there was a risk they'd have to change their command, but it's still going to be a behavioral change they might not expect.) Further, when I brought up changing the behavior of commands during sparse-checkouts to limit to files matching the sparsity paths in that old thread at [1], Stolee was a bit skeptical of making that the default. That suggests, at least, that two independent groups of users would want to use the non-sparse searching frequently, and frequently enough that they'd appreciate a config option.

I also brought up in that old thread that perhaps we want to avoid adding a flag to every subcommand, and instead just having a git-global flag for triggering this type of behavior. (e.g. `git --no-restrict grep --cached ...` or `git --dense grep --cached ...`).

[1] https://lore.kernel.org/git/CABPp-BGJ_Nvi5TmgriD9Bh6eNXE2EDq2f8e8QKXAeYG3BxZafA@mail.gmail.com/ and the responses to that email.

Show 5 quoted lines
> Change the default behavior of 'git grep' to focus on the files within
> the sparse-checkout definition. To enable the previous behavior, add a
> '--sparse' option to 'git grep' that triggers the old behavior that
> inspects paths outside of the sparse-checkout definition when paired
> with the '--cached' option.

I still think the flag name of `--sparse` is totally backwards and highly confusing for the described behavior. I missed Stolee's email at the time (wasn't cc'ed) where he brought up that "--sparse" had already been added to "git-add" and "git-rm", but in those cases the commands aren't querying and I just don't see how they lead to the same level of user confusion. This one seems glaringly wrong to me and both Junio and I flagged it on v1 when we first saw it. (Perhaps it also helps that for the add/rm cases, that a user is often given an error message with the suggested flag to use, which just doesn't make sense here either.) If there is concern that this flag should be the same as add and rm, then I think we need to do the backward compatibility dance and fix add and rm by adding an alias over there so that grep's flag won't be so confusing.

I really don't want to have to deal with the backward compatibility headache of "git grep --sparse" means do a non-sparse search for backward compatibility reasons. Here's the flag you should really use..."

Show 148 quoted lines
> Suggested-by: Victoria Dye <vdye@github.com>
> Helped-by: Derrick Stolee <derrickstolee@github.com>
> Helped-by: Victoria Dye <vdye@github.com>
> Signed-off-by: Shaoxuan Yuan <shaoxuan.yuan02@gmail.com>
> ---
>  Documentation/git-grep.txt      |  5 ++++-
>  builtin/grep.c                  | 10 +++++++++-
>  t/t7817-grep-sparse-checkout.sh | 34 +++++++++++++++++++++++++++------
>  3 files changed, 41 insertions(+), 8 deletions(-)
>
> diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt
> index 58d944bd57..bdd3d5b8a6 100644
> --- a/Documentation/git-grep.txt
> +++ b/Documentation/git-grep.txt
> @@ -28,7 +28,7 @@ SYNOPSIS
>            [-f <file>] [-e] <pattern>
>            [--and|--or|--not|(|)|-e <pattern>...]
>            [--recurse-submodules] [--parent-basename <basename>]
> -          [ [--[no-]exclude-standard] [--cached | --no-index | --untracked] | <tree>...]
> +          [ [--[no-]exclude-standard] [--cached [--sparse] | --no-index | --untracked] | <tree>...]
>            [--] [<pathspec>...]
>
>  DESCRIPTION
> @@ -45,6 +45,9 @@ OPTIONS
>         Instead of searching tracked files in the working tree, search
>         blobs registered in the index file.
>
> +--sparse::
> +       Use with --cached. Search outside of sparse-checkout definition.
> +
>  --no-index::
>         Search files in the current directory that is not managed by Git.
>
> diff --git a/builtin/grep.c b/builtin/grep.c
> index e6bcdf860c..12abd832fa 100644
> --- a/builtin/grep.c
> +++ b/builtin/grep.c
> @@ -96,6 +96,8 @@ static pthread_cond_t cond_result;
>
>  static int skip_first_line;
>
> +static int grep_sparse = 0;
> +
>  static void add_work(struct grep_opt *opt, struct grep_source *gs)
>  {
>         if (opt->binary != GREP_BINARY_TEXT)
> @@ -525,7 +527,11 @@ static int grep_cache(struct grep_opt *opt,
>         for (nr = 0; nr < repo->index->cache_nr; nr++) {
>                 const struct cache_entry *ce = repo->index->cache[nr];
>
> -               if (!cached && ce_skip_worktree(ce))
> +               /*
> +                * Skip entries with SKIP_WORKTREE unless both --sparse and
> +                * --cached are given.
> +                */
> +               if (!(grep_sparse && cached) && ce_skip_worktree(ce))
>                         continue;
>
>                 strbuf_setlen(&name, name_base_len);
> @@ -963,6 +969,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
>                            PARSE_OPT_NOCOMPLETE),
>                 OPT_INTEGER('m', "max-count", &opt.max_count,
>                         N_("maximum number of results per file")),
> +               OPT_BOOL(0, "sparse", &grep_sparse,
> +                        N_("search the contents of files outside the sparse-checkout definition")),
>                 OPT_END()
>         };
>         grep_prefix = prefix;
> diff --git a/t/t7817-grep-sparse-checkout.sh b/t/t7817-grep-sparse-checkout.sh
> index eb59564565..a9879cc980 100755
> --- a/t/t7817-grep-sparse-checkout.sh
> +++ b/t/t7817-grep-sparse-checkout.sh
> @@ -118,13 +118,19 @@ test_expect_success 'grep searches unmerged file despite not matching sparsity p
>         test_cmp expect actual
>  '
>
> -test_expect_success 'grep --cached searches entries with the SKIP_WORKTREE bit' '
> +test_expect_success 'grep --cached and --sparse searches entries with the SKIP_WORKTREE bit' '
> +       cat >expect <<-EOF &&
> +       a:text
> +       EOF
> +       git grep --cached "text" >actual &&
> +       test_cmp expect actual &&
> +
>         cat >expect <<-EOF &&
>         a:text
>         b:text
>         dir/c:text
>         EOF
> -       git grep --cached "text" >actual &&
> +       git grep --cached --sparse "text" >actual &&
>         test_cmp expect actual
>  '
>
> @@ -143,7 +149,15 @@ test_expect_success 'grep --recurse-submodules honors sparse checkout in submodu
>         test_cmp expect actual
>  '
>
> -test_expect_success 'grep --recurse-submodules --cached searches entries with the SKIP_WORKTREE bit' '
> +test_expect_success 'grep --recurse-submodules --cached and --sparse searches entries with the SKIP_WORKTREE bit' '
> +       cat >expect <<-EOF &&
> +       a:text
> +       sub/B/b:text
> +       sub2/a:text
> +       EOF
> +       git grep --recurse-submodules --cached "text" >actual &&
> +       test_cmp expect actual &&
> +
>         cat >expect <<-EOF &&
>         a:text
>         b:text
> @@ -152,7 +166,7 @@ test_expect_success 'grep --recurse-submodules --cached searches entries with th
>         sub/B/b:text
>         sub2/a:text
>         EOF
> -       git grep --recurse-submodules --cached "text" >actual &&
> +       git grep --recurse-submodules --cached --sparse "text" >actual &&
>         test_cmp expect actual
>  '
>
> @@ -166,7 +180,15 @@ test_expect_success 'working tree grep does not search the index with CE_VALID a
>         test_cmp expect actual
>  '
>
> -test_expect_success 'grep --cached searches index entries with both CE_VALID and SKIP_WORKTREE' '
> +test_expect_success 'grep --cached and --sparse searches index entries with both CE_VALID and SKIP_WORKTREE' '
> +       cat >expect <<-EOF &&
> +       a:text
> +       EOF
> +       test_when_finished "git update-index --no-assume-unchanged b" &&
> +       git update-index --assume-unchanged b &&
> +       git grep --cached text >actual &&
> +       test_cmp expect actual &&
> +
>         cat >expect <<-EOF &&
>         a:text
>         b:text
> @@ -174,7 +196,7 @@ test_expect_success 'grep --cached searches index entries with both CE_VALID and
>         EOF
>         test_when_finished "git update-index --no-assume-unchanged b" &&
>         git update-index --assume-unchanged b &&
> -       git grep --cached text >actual &&
> +       git grep --cached --sparse text >actual &&
>         test_cmp expect actual
>  '
>
> --
> 2.37.0

I read over this patch and the other two patches. Other than things like variable names propagating the sparse/dense confusion, and the high level goals already discussed, I didn't spot any other issues.

Previous: Victoria DyeNext: Junio C Hamano
Message 41 of 69 in “grep: integrate with sparse index”
  1. 0/2 grep: integrate with sparse indexShaoxuan Yuan, Aug 17, 2022
  2. 1/2 builtin/grep.c: add --sparse optionShaoxuan Yuan, Aug 17, 2022
  3. Derrick StoleeAug 17, 2022
  4. Junio C HamanoAug 17, 2022
  5. Victoria DyeAug 17, 2022
  6. Derrick StoleeAug 17, 2022
  7. Junio C HamanoAug 17, 2022
  8. Elijah NewrenAug 17, 2022
  9. Shaoxuan YuanAug 24, 2022
  10. Derrick StoleeAug 24, 2022
  11. 2/2 builtin/grep.c: integrate with sparse indexShaoxuan Yuan, Aug 17, 2022
  12. Derrick StoleeAug 17, 2022
  13. Shaoxuan YuanAug 24, 2022
  14. Derrick StoleeAug 25, 2022
  15. Derrick StoleeAug 17, 2022
  16. 0/2 grep: integrate with sparse indexShaoxuan Yuan, Aug 29, 2022
  17. 2/2 builtin/grep.c: integrate with sparse indexShaoxuan Yuan, Aug 29, 2022
  18. Derrick StoleeAug 30, 2022
  19. 1/2 builtin/grep.c: add --sparse optionShaoxuan Yuan, Aug 29, 2022
  20. 0/3 grep: integrate with sparse indexShaoxuan Yuan, Sep 1, 2022
  21. 1/3 builtin/grep.c: add --sparse optionShaoxuan Yuan, Sep 1, 2022
  22. 2/3 builtin/grep.c: integrate with sparse indexShaoxuan Yuan, Sep 1, 2022
  23. 3/3 builtin/grep.c: walking tree instead of expanding index with --sparseShaoxuan Yuan, Sep 1, 2022
  24. Derrick StoleeSep 1, 2022
  25. Shaoxuan YuanSep 1, 2022
  26. Junio C HamanoSep 1, 2022
  27. Junio C HamanoSep 1, 2022
  28. Shaoxuan YuanSep 1, 2022
  29. Shaoxuan YuanSep 1, 2022
  30. Victoria DyeSep 2, 2022
  31. Shaoxuan YuanSep 2, 2022
  32. 0/3 grep: integrate with sparse indexShaoxuan Yuan, Sep 3, 2022
  33. 1/3 builtin/grep.c: add --sparse optionShaoxuan Yuan, Sep 3, 2022
  34. 2/3 builtin/grep.c: integrate with sparse indexShaoxuan Yuan, Sep 3, 2022
  35. 3/3 builtin/grep.c: walking tree instead of expanding index with --sparseShaoxuan Yuan, Sep 3, 2022
  36. Junio C HamanoSep 3, 2022
  37. Shaoxuan YuanSep 8, 2022
  38. 0/3 grep: integrate with sparse indexShaoxuan Yuan, Sep 8, 2022
  39. 1/3 builtin/grep.c: add --sparse optionShaoxuan Yuan, Sep 8, 2022
  40. Victoria DyeSep 10, 2022
  41. Elijah NewrenSep 14, 2022
  42. Junio C HamanoSep 15, 2022
  43. Elijah NewrenSep 18, 2022
  44. Victoria DyeSep 18, 2022
  45. Junio C HamanoSep 19, 2022
  46. Shaoxuan YuanSep 19, 2022
  47. Ævar Arnfjörð BjarmasonSep 19, 2022
  48. Elijah NewrenSep 20, 2022
  49. Shaoxuan YuanSep 17, 2022
  50. Elijah NewrenSep 18, 2022
  51. Shaoxuan YuanSep 19, 2022
  52. Shaoxuan YuanSep 17, 2022
  53. 2/3 builtin/grep.c: integrate with sparse indexShaoxuan Yuan, Sep 8, 2022
  54. 3/3 builtin/grep.c: walking tree instead of expanding index with --sparseShaoxuan Yuan, Sep 8, 2022
  55. Junio C HamanoSep 8, 2022
  56. Derrick StoleeSep 8, 2022
  57. Junio C HamanoSep 8, 2022
  58. Shaoxuan YuanSep 8, 2022
  59. Derrick StoleeSep 9, 2022
  60. Junio C HamanoSep 13, 2022
  61. Victoria DyeSep 10, 2022
  62. 0/1 grep: integrate with sparse indexShaoxuan Yuan, Sep 23, 2022
  63. 1/1 builtin/grep.c: integrate with sparse indexShaoxuan Yuan, Sep 23, 2022
  64. Junio C HamanoSep 23, 2022
  65. Junio C HamanoSep 23, 2022
  66. Junio C HamanoSep 26, 2022
  67. Derrick StoleeSep 23, 2022
  68. Victoria DyeSep 23, 2022
  69. Junio C HamanoSep 23, 2022

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