[PATCH/RFC] grep: add a perlRegexp configuration option

[J Smith <dark.panda@gmail.com>]

Enables the -P flag for perl regexps by default. When both the
perlRegexp and extendedRegexp options are enabled, the last enabled
option wins.
---
 Documentation/config.txt   |  6 ++++++
 Documentation/git-grep.txt |  6 ++++++
 builtin/grep.c             | 17 +++++++++++++++--
 t/t7810-grep.sh            | 34 ++++++++++++++++++++++++++++++++++
 4 files changed, 61 insertions(+), 2 deletions(-)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index a95e5a4..ff3019b 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1213,6 +1213,12 @@ grep.lineNumber::
 grep.extendedRegexp::
 	If set to true, enable '--extended-regexp' option by default.

+grep.perlRegexp::
+	If set to true, enable '--perl-regexp' option by default.
+
+When both the 'grep.extendedRegexp' and 'grep.perlRegexp' options
+are used, the last enabled option wins.
+
 gpg.program::
 	Use this custom program instead of "gpg" found on $PATH when
 	making or verifying a PGP signature. The program must support the
diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt
index 3bec036..8816968 100644
--- a/Documentation/git-grep.txt
+++ b/Documentation/git-grep.txt
@@ -45,6 +45,12 @@ grep.lineNumber::
 grep.extendedRegexp::
 	If set to true, enable '--extended-regexp' option by default.

+grep.perlRegexp::
+	If set to true, enable '--perl-regexp' option by default.
+
+When both the 'grep.extendedRegexp' and 'grep.perlRegexp' options
+are used, the last enabled option wins.
+

 OPTIONS
 -------
diff --git a/builtin/grep.c b/builtin/grep.c
index 29adb0a..b4475e6 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -268,11 +268,24 @@ static int grep_config(const char *var, const char *value, void *cb)
 	if (userdiff_config(var, value) < 0)
 		return -1;

+	if (!strcmp(var, "grep.perlregexp")) {
+		if (git_config_bool(var, value)) {
+			opt->fixed = 0;
+			opt->pcre = 1;
+		} else {
+			opt->pcre = 0;
+		}
+		return 0;
+	}
+
 	if (!strcmp(var, "grep.extendedregexp")) {
-		if (git_config_bool(var, value))
+		if (git_config_bool(var, value)) {
 			opt->regflags |= REG_EXTENDED;
-		else
+			opt->pcre = 0;
+			opt->fixed = 0;
+		} else {
 			opt->regflags &= ~REG_EXTENDED;
+		}
 		return 0;
 	}

diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index 24e9b19..5479dc9 100755
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -729,6 +729,40 @@ test_expect_success LIBPCRE 'grep -P pattern' '
 	test_cmp expected actual
 '

+test_expect_success LIBPCRE 'grep pattern with grep.perlRegexp=true' '
+	git \
+		-c grep.perlregexp=true \
+		grep "\p{Ps}.*?\p{Pe}" hello.c >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success LIBPCRE 'grep pattern with grep.perlRegexp=true and then grep.extendedRegexp=true' '
+	test_must_fail git \
+		-c grep.perlregexp=true \
+		-c grep.extendedregexp=true \
+		grep "\p{Ps}.*?\p{Pe}" hello.c
+'
+
+test_expect_success LIBPCRE 'grep pattern with grep.extendedRegexp=true and then grep.perlRegexp=true' '
+	git \
+		-c grep.extendedregexp=true \
+		-c grep.perlregexp=true \
+		grep "\p{Ps}.*?\p{Pe}" hello.c >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success LIBPCRE 'grep -E pattern with grep.perlRegexp=true' '
+	test_must_fail git \
+		-c grep.perlregexp=true \
+		grep -E "\p{Ps}.*?\p{Pe}" hello.c
+'
+
+test_expect_success LIBPCRE 'grep -G pattern with grep.perlRegexp=true' '
+	test_must_fail git \
+		-c grep.perlregexp=true \
+		grep -G "\p{Ps}.*?\p{Pe}" hello.c
+'
+
 test_expect_success 'grep pattern with grep.extendedRegexp=true' '
 	>empty &&
 	test_must_fail git -c grep.extendedregexp=true \
--
1.7.11.3