grep: add tests for grep pattern types being passed to submodules

Add testing for grep pattern types being correctly passed to
submodules. The pattern "(.|.)[\d]" matches differently under
fixed (not at all), and then matches different lines under
basic/extended & perl regular expressions, so this change asserts that
the pattern type is passed along correctly.
Signed-off-by: NÆvar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

t/t7814-grep-recurse-submodules.sh

@@ -313,4 +313,53 @@ test_incompatible_with_recurse_submodules ()
 test_incompatible_with_recurse_submodules --untracked
 test_incompatible_with_recurse_submodules --no-index
 
+test_expect_success 'grep --recurse-submodules should pass the pattern type along' '
+	# Fixed
+	test_must_fail git grep -F --recurse-submodules -e "(.|.)[\d]" &&
+	test_must_fail git -c grep.patternType=fixed grep --recurse-submodules -e "(.|.)[\d]" &&
+
+	# Basic
+	git grep -G --recurse-submodules -e "(.|.)[\d]" >actual &&
+	cat >expect <<-\EOF &&
+	a:(1|2)d(3|4)
+	submodule/a:(1|2)d(3|4)
+	submodule/sub/a:(1|2)d(3|4)
+	EOF
+	test_cmp expect actual &&
+	git -c grep.patternType=basic grep --recurse-submodules -e "(.|.)[\d]" >actual &&
+	test_cmp expect actual &&
+
+	# Extended
+	git grep -E --recurse-submodules -e "(.|.)[\d]" >actual &&
+	cat >expect <<-\EOF &&
+	.gitmodules:[submodule "submodule"]
+	.gitmodules:	path = submodule
+	.gitmodules:	url = ./submodule
+	a:(1|2)d(3|4)
+	submodule/.gitmodules:[submodule "sub"]
+	submodule/a:(1|2)d(3|4)
+	submodule/sub/a:(1|2)d(3|4)
+	EOF
+	test_cmp expect actual &&
+	git -c grep.patternType=extended grep --recurse-submodules -e "(.|.)[\d]" >actual &&
+	test_cmp expect actual &&
+	git -c grep.extendedRegexp=true grep --recurse-submodules -e "(.|.)[\d]" >actual &&
+	test_cmp expect actual &&
+
+	# Perl
+	if test_have_prereq PCRE
+	then
+		git grep -P --recurse-submodules -e "(.|.)[\d]" >actual &&
+		cat >expect <<-\EOF &&
+		a:(1|2)d(3|4)
+		b/b:(3|4)
+		submodule/a:(1|2)d(3|4)
+		submodule/sub/a:(1|2)d(3|4)
+		EOF
+		test_cmp expect actual &&
+		git -c grep.patternType=perl grep --recurse-submodules -e "(.|.)[\d]" >actual &&
+		test_cmp expect actual
+	fi
+'
+
 test_done