dir: warn about trailing spaces in exclude patterns

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

dir.c

@@ -463,6 +463,22 @@ void clear_exclude_list(struct exclude_list *el)
 	el->filebuf = NULL;
 }
 
+static void check_trailing_spaces(const char *fname, char *buf)
+{
+	int i, last_space = -1, len = strlen(buf);
+	for (i = 0; i < len; i++)
+		if (buf[i] == '\\')
+			i++;
+		else if (buf[i] == ' ')
+			last_space = i;
+		else
+			last_space = -1;
+
+	if (last_space == len - 1)
+		warning(_("%s: trailing spaces in '%s'. Please quote or remove them."),
+			fname, buf);
+}
+
 int add_excludes_from_file_to_list(const char *fname,
 				   const char *base,
 				   int baselen,
@@ -514,6 +530,7 @@ int add_excludes_from_file_to_list(const char *fname,
 		if (buf[i] == '\n') {
 			if (entry != buf + i && entry[0] != '#') {
 				buf[i - (i && buf[i-1] == '\r')] = 0;
+				check_trailing_spaces(fname, entry);
 				add_exclude(entry, base, baselen, el, lineno);
 			}
 			lineno++;

t/t0008-ignores.sh

@@ -775,4 +775,35 @@ test_expect_success PIPE 'streaming support for --stdin' '
 	echo "$response" | grep "^::	two"
 '
 
+############################################################################
+#
+# test whitespace handling
+
+test_expect_success 'trailing whitespace is warned' '
+	mkdir whitespace &&
+	>whitespace/trailing &&
+	>whitespace/untracked &&
+	echo "whitespace/trailing   " >ignore &&
+	cat >expect <<EOF &&
+whitespace/trailing
+whitespace/untracked
+EOF
+	git ls-files -o -X ignore whitespace >actual 2>err &&
+	grep "ignore:.*'\''whitespace/trailing   '\''" err &&
+	test_cmp expect actual
+'
+
+test_expect_success 'quoting allows trailing whitespace' '
+	rm -rf whitespace &&
+	mkdir whitespace &&
+	>"whitespace/trailing  " &&
+	>whitespace/untracked &&
+	echo "whitespace/trailing\\ \\ " >ignore &&
+	echo whitespace/untracked >expect &&
+	: >err.expect &&
+	git ls-files -o -X ignore whitespace >actual 2>err &&
+	test_cmp expect actual &&
+	test_cmp err.expect err
+'
+
 test_done