git-grep: Bail out when -P is used with -F or -E

This patch makes git-grep die() when -P is used on command line together
with -E/--extended-regexp or -F/--fixed-strings.

This also makes it bail out when grep.extendedRegexp is enabled.

But `git grep -G -P pattern` and `git grep -E -G -P pattern` still work
because -G and -E set opts.regflags during parse_options() and there is
no way to detect `-G` or `-E -G`.

Signed-off-by: Michał Kiedrowicz <michal.kiedrowicz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index e845218..2a31eca 100755
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -637,4 +637,20 @@ test_expect_success LIBPCRE 'grep -P -w pattern' '
 	test_cmp expected actual
 '
 
+test_expect_success LIBPCRE 'grep -P -F returns error' '
+	test_expect_code 128 git grep -P -F main
+'
+
+test_expect_success LIBPCRE 'grep -P -E returns error' '
+	test_expect_code 128 git grep -P -E main
+'
+
+test_expect_failure LIBPCRE 'grep -P -G returns error' '
+	test_expect_code 128 git grep -P -G main
+'
+
+test_expect_failure LIBPCRE 'grep -P -E -G returns error' '
+	test_expect_code 128 git grep -P -E -G main
+'
+
 test_done