attr: support quoting pathname patterns in C style

Full pattern must be quoted. So 'pat"t"ern attr' will give exactly
'pat"t"ern', not 'pattern'. Also clarify that leading whitespaces are
not part of the pattern and document comment syntax.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

3 files changed, 44 insertions, 5 deletions

diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index e0b66c1220..3173dee7ed 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -21,9 +21,11 @@ Each line in `gitattributes` file is of form:
 	pattern	attr1 attr2 ...
 
 That is, a pattern followed by an attributes list,
-separated by whitespaces.  When the pattern matches the
-path in question, the attributes listed on the line are given to
-the path.
+separated by whitespaces. Leading and trailing whitespaces are
+ignored. Lines that begin with '#' are ignored. Patterns
+that begin with a double quote are quoted in C style.
+When the pattern matches the path in question, the attributes
+listed on the line are given to the path.
 
 Each attribute can be in one of these states for a given path:
 
diff --git a/attr.c b/attr.c
index d180c7833e..e1c630f79b 100644
--- a/attr.c
+++ b/attr.c
@@ -13,6 +13,7 @@
 #include "attr.h"
 #include "dir.h"
 #include "utf8.h"
+#include "quote.h"
 
 const char git_attr__true[] = "(builtin)true";
 const char git_attr__false[] = "\0(builtin)false";
@@ -212,12 +213,21 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
 	const char *cp, *name, *states;
 	struct match_attr *res = NULL;
 	int is_macro;
+	struct strbuf pattern = STRBUF_INIT;
 
 	cp = line + strspn(line, blank);
 	if (!*cp || *cp == '#')
 		return NULL;
 	name = cp;
-	namelen = strcspn(name, blank);
+
+	if (*cp == '"' && !unquote_c_style(&pattern, name, &states)) {
+		name = pattern.buf;
+		namelen = pattern.len;
+	} else {
+		namelen = strcspn(name, blank);
+		states = name + namelen;
+	}
+
 	if (strlen(ATTRIBUTE_MACRO_PREFIX) < namelen &&
 	    starts_with(name, ATTRIBUTE_MACRO_PREFIX)) {
 		if (!macro_ok) {
@@ -239,7 +249,6 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
 	else
 		is_macro = 0;
 
-	states = name + namelen;
 	states += strspn(states, blank);
 
 	/* First pass to count the attr_states */
@@ -282,9 +291,11 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
 			cannot_trust_maybe_real = 1;
 	}
 
+	strbuf_release(&pattern);
 	return res;
 
 fail_return:
+	strbuf_release(&pattern);
 	free(res);
 	return NULL;
 }
diff --git a/t/t0003-attributes.sh b/t/t0003-attributes.sh
index f0fbb42554..f19ae4f8cc 100755
--- a/t/t0003-attributes.sh
+++ b/t/t0003-attributes.sh
@@ -13,10 +13,31 @@ attr_check () {
 	test_line_count = 0 err
 }
 
+attr_check_quote () {
+
+	path="$1"
+	quoted_path="$2"
+	expect="$3"
+
+	git check-attr test -- "$path" >actual &&
+	echo "\"$quoted_path\": test: $expect" >expect &&
+	test_cmp expect actual
+
+}
+
+test_expect_success 'open-quoted pathname' '
+	echo "\"a test=a" >.gitattributes &&
+	test_must_fail attr_check a a
+'
+
+
 test_expect_success 'setup' '
 	mkdir -p a/b/d a/c b &&
 	(
 		echo "[attr]notest !test"
+		echo "\" d \"	test=d"
+		echo " e	test=e"
+		echo " e\"	test=e"
 		echo "f	test=f"
 		echo "a/i test=a/i"
 		echo "onoff test -test"
@@ -69,6 +90,11 @@ test_expect_success 'command line checks' '
 '
 
 test_expect_success 'attribute test' '
+
+	attr_check " d " d &&
+	attr_check e e &&
+	attr_check_quote e\" e\\\" e &&
+
 	attr_check f f &&
 	attr_check a/f f &&
 	attr_check a/c/f f &&