From: Shaoxuan Yuan Date: Wed, 24 Aug 2022 18:20:27 GMT Subject: Re: [PATCH v1 1/2] builtin/grep.c: add --sparse option Message-ID: <74ff1a97-fa98-7280-9d84-35dafaf3cb3d@gmail.com> In-Reply-To: <80f24382-1188-d450-d1e2-42f68c08e60b@github.com> Hi reviewrs, I came back from busying with relocation :) On 8/17/2022 10:12 PM, Derrick Stolee wrote: > On 8/17/2022 3:56 AM, Shaoxuan Yuan wrote: >> Add a --sparse option to `git-grep`. This option is mainly used to: >> >> If searching in the index (using --cached): >> >> With --sparse, proceed the action when the current cache_entry is > > This phrasing is awkward. It might be better to reframe to describe the > _why_ before the _what_ > >   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. > >   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. Good suggestion! > Or something like that. The documentation updates will also help clarify > what happens when '--cached' is not included. I assume '--sparse' is > ignored, but perhaps it _could_ allow looking at the cached files outside > the sparse-checkout definition, this could make the simpler invocation of > 'git grep --sparse ' be the way that users can search after their > attempt to search the worktree failed. This simpler version was in my earlier local branch, but later I decided not to go with it. I found the difference between these two approaches, is that "--cached --sparse" is more correct in terms of how Git actually works (because sparsity is a concept in the index); and "--sparse" is more comfortable for the end user. I found the former one better here, because it is more self-explanatory, and thus more info for the user, i.e. "you are now looking at the index, and Git will also consider files outside of sparse definition." To be honest, I don't know which one is "better", but I think I'll keep the current implementation unless something more convincing shows up later. >> marked with SKIP_WORKTREE bit (the default is to skip this kind of >> entry). Before this patch, --cached itself can realize this action. >> Adding --sparse here grants the user finer control over sparse >> entries. If the user only wants to peak into the index without > > s/peak/peek/ > >> caring about sparse entries, --cached should suffice; if the user >> wants to peak into the index _and_ cares about sparse entries, >> combining --sparse with --cached can address this need. >> >> Suggested-by: Victoria Dye >> Signed-off-by: Shaoxuan Yuan >> --- >>  builtin/grep.c                  | 10 +++++++++- >>  t/t7817-grep-sparse-checkout.sh | 12 ++++++------ >>  2 files changed, 15 insertions(+), 7 deletions(-) > > You mentioned in Slack that you missed the documentation of the --sparse > option. Just pointing it out here so we don't forget. Will do. >> >> diff --git a/builtin/grep.c b/builtin/grep.c >> index e6bcdf860c..61402e8084 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; >> + > > I initially thought it might be good to not define an additional global, > but there are many defined in this file outside of the context and they > are spread out with extra whitespace like this. > >>  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)) > > This logic would skip files marked with SKIP_WORKTREE _unless_ --cached > was provided. > >> +        /* >> +         * If ce is a SKIP_WORKTREE entry, look into it when both >> +         * --sparse and --cached are given. >> +         */ >> +        if (!(grep_sparse && cached) && ce_skip_worktree(ce)) >>              continue; > > The logic of this if statement is backwards from the comment because a > true statement means "skip the entry" _not_ "look into it". > >     /* >      * Skip entries with SKIP_WORKTREE unless both --sparse and >      * --cached are given. >      */ Got it. > But again, we might want to consider this alternative: > >     /* >      * Skip entries with SKIP_WORKTREE unless --sparse is given. >      */ >     if (!grep_sparse && ce_skip_worktree(ce)) >         continue; > > This will require further changes below, specifically this bit: > >             /* >              * If CE_VALID is on, we assume worktree file and its >              * cache entry are identical, even if worktree file has >              * been modified, so use cache version instead >              */ >             if (cached || (ce->ce_flags & CE_VALID)) { >                 if (ce_stage(ce) || ce_intent_to_add(ce)) >                     continue; >                 hit |= grep_oid(opt, &ce->oid, name.buf, >                          0, name.buf); >             } else { > > We need to activate this grep_oid() call also when ce_skip_worktree(c) is > true. That is, if we want 'git grep --sparse' to extend the search beyond > the worktree and into the sparse entries. > >> >>          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 sparse contents and expand sparse index")), > > This "and expand sparse index" is an internal implementation detail, not a > heplful item for the help text. Instead, perhaps: > >     "search the contents of files outside the sparse-checkout definition" Sounds good! > (Also, while the sparse index is being expanded right now, I would expect > to not expand the sparse index by the end of the series.) > >> -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 >>      b:text >>      dir/c:text >>      EOF >> -    git grep --cached "text" >actual && >> +    git grep --cached --sparse "text" >actual && >>      test_cmp expect actual >>  ' > > Please add a test that demonstrates the change of behavior when only --cached > is provided, not --sparse. Sure! > (If you take my suggestion to allow 'git grep --sparse' to do something > different, then also add a test for that case.) > >> >> @@ -143,7 +143,7 @@ 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 >>      b:text >> @@ -152,7 +152,7 @@ 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 +166,7 @@ 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 >>      b:text >> @@ -174,7 +174,7 @@ 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 >>  ' > > Same with these two tests. Add additional commands that show the change of > behavior when only using '--cached'. -- Thanks, Shaoxuan