[PATCH 05/12] log: add exhaustive tests for pattern style options & config

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Add exhaustive tests for how the different grep.patternType options &
the corresponding command-line options affect git-log.

Before this change it was possible to patch revision.c so that the
--basic-regexp option was synonymous with --extended-regexp, and
--perl-regexp wasn't recognized at all, and still have 100% of the
test suite pass.

This was because the first test being modified here, added in commit
34a4ae55b2 ("log --grep: use the same helper to set -E/-F options as
"git grep"", 2012-10-03), didn't actually check whether we'd enabled
extended regular expressions as distinct from re-toggling non-fixed
string support.

Fix that by changing the pattern to a pattern that'll only match if
--extended-regexp option is provided, but won't match under the
default --basic-regexp option.

Other potential regressions were possible since there were no tests
for the rest of the combinations of grep.patternType configuration
toggles & corresponding git-log command-line options. Add exhaustive
tests for those.

The patterns being passed to fixed/basic/extended/PCRE are carefully
crafted to return the wrong thing if the grep engine were to pick any
other matching method than the one it's told to use.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 t/t4202-log.sh | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 66 insertions(+), 1 deletion(-)

diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index 48b55bfd27..00d0585253 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -261,7 +261,13 @@ test_expect_success 'log --grep -i' '
 
 test_expect_success 'log -F -E --grep=<ere> uses ere' '
 	echo second >expect &&
-	git log -1 --pretty="tformat:%s" -F -E --grep=s.c.nd >actual &&
+	git log -1 --pretty="tformat:%s" -F -E --grep="(s).c.nd" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success LIBPCRE 'log -F -E --perl-regexp --grep=<pcre> uses PCRE' '
+	echo second >expect &&
+	git log -1 --pretty="tformat:%s" -F -E --perl-regexp --grep="s(?=ec)econd" >actual &&
 	test_cmp expect actual
 '
 
@@ -279,6 +285,65 @@ test_expect_success 'log with grep.patternType configuration and command line' '
 	test_cmp expect actual
 '
 
+test_expect_success 'log with various grep.patternType configurations & command-lines' '
+	git init pattern-type &&
+	(
+		cd pattern-type &&
+		test_commit 1 file A &&
+		test_commit "(1|2)" file B &&
+
+		echo "(1|2)" >expect.fixed &&
+		cp expect.fixed expect.basic &&
+		cp expect.fixed expect.extended &&
+		cp expect.fixed expect.perl &&
+
+		git -c grep.patternType=fixed log --pretty=tformat:%s \
+			--grep="(1|2)" >actual.fixed &&
+		git -c grep.patternType=basic log --pretty=tformat:%s \
+			--grep="(.|.)" >actual.basic &&
+		git -c grep.patternType=extended log --pretty=tformat:%s \
+			--grep="\|2" >actual.extended &&
+		if test_have_prereq LIBPCRE
+		then
+			git -c grep.patternType=perl log --pretty=tformat:%s \
+				--grep="\((?=1)" >actual.perl
+		fi &&
+		test_cmp expect.fixed actual.fixed &&
+		test_cmp expect.basic actual.basic &&
+		test_cmp expect.extended actual.extended &&
+		if test_have_prereq LIBPCRE
+		then
+			test_cmp expect.perl actual.perl
+		fi &&
+
+		git log --pretty=tformat:%s -F \
+			--grep="(1|2)" >actual.fixed.short-arg &&
+		git log --pretty=tformat:%s -E \
+			--grep="\|2" >actual.extended.short-arg &&
+		test_cmp expect.fixed actual.fixed.short-arg &&
+		test_cmp expect.extended actual.extended.short-arg &&
+
+		git log --pretty=tformat:%s --fixed-strings \
+			--grep="(1|2)" >actual.fixed.long-arg &&
+		git log --pretty=tformat:%s --basic-regexp \
+			--grep="(.|.)" >actual.basic.long-arg &&
+		git log --pretty=tformat:%s --extended-regexp \
+			--grep="\|2" >actual.extended.long-arg &&
+		if test_have_prereq LIBPCRE
+		then
+			git log --pretty=tformat:%s --perl-regexp \
+				--grep="\((?=1)" >actual.perl.long-arg
+		fi &&
+		test_cmp expect.fixed actual.fixed.long-arg &&
+		test_cmp expect.basic actual.basic.long-arg &&
+		test_cmp expect.extended actual.extended.long-arg &&
+		if test_have_prereq LIBPCRE
+		then
+			test_cmp expect.perl actual.perl.long-arg
+		fi
+	)
+'
+
 cat > expect <<EOF
 * Second
 * sixth
-- 
2.11.0