Re: [PATCH v3 1/3] revision: complicated pathspecs disable filters

["SZEDER Gábor" <szeder.dev@gmail.com>]

On Thu, Apr 16, 2020 at 08:14:02PM +0000, Derrick Stolee via GitGitGadget wrote:
> From: Derrick Stolee <dstolee@microsoft.com>
> 
> The changed-path Bloom filters work only when we can compute an
> explicit Bloom filter key in advance. When a pathspec is given
> that allows case-insensitive checks or wildcard matching, we
> must disable the Bloom filter performance checks.
> 
> By checking the pathspec in prepare_to_use_bloom_filters(), we
> avoid setting up the Bloom filter data and thus revert to the
> usual logic.
> 
> Before this change, the following tests would fail*:
> 
> 	t6004-rev-list-path-optim.sh (Tests 6-7)
> 	t6130-pathspec-noglob.sh (Tests 3-6)
> 	t6131-pathspec-icase.sh (Tests 3-5)
> 
> *These tests would fail when using GIT_TEST_COMMIT_GRAPH and
> GIT_TEST_COMMIT_GRAPH_BLOOM_FILTERS except that the latter
> environment variable was not set up correctly to write the changed-
> path Bloom filters in the test suite. That will be fixed in the
> next change.
> 
> Helped-by: Taylor Blau <me@ttaylorr.com>
> Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
> ---
>  revision.c | 19 ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/revision.c b/revision.c
> index 2b06ee739c8..f78c636e4d0 100644
> --- a/revision.c
> +++ b/revision.c
> @@ -650,6 +650,20 @@ static void trace2_bloom_filter_statistics_atexit(void)
>  	jw_release(&jw);
>  }
>  
> +static int forbid_bloom_filters(struct pathspec *spec)
> +{
> +	if (spec->has_wildcard)
> +		return 1;
> +	if (spec->nr > 1)
> +		return 1;
> +	if (spec->magic & ~PATHSPEC_LITERAL)

Nit: spec->magic is the bitwise OR combination of all
spec->items[i].magic, so checking the latter below is unnecessary.

> +		return 1;
> +	if (spec->nr && (spec->items[0].magic & ~PATHSPEC_LITERAL))
> +		return 1;
> +
> +	return 0;
> +}
> +
>  static void prepare_to_use_bloom_filter(struct rev_info *revs)
>  {
>  	struct pathspec_item *pi;
> @@ -659,7 +673,10 @@ static void prepare_to_use_bloom_filter(struct rev_info *revs)
>  	int len;
>  
>  	if (!revs->commits)
> -	    return;
> +		return;
> +
> +	if (forbid_bloom_filters(&revs->prune_data))
> +		return;
>  
>  	repo_parse_commit(revs->repo, revs->commits->item);
>  
> -- 
> gitgitgadget
>