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

["Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>]

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)
+		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);
 
-- 
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