config: report errors at the EOL with correct line number

A section in a config file with a missing "]" reports the next line
as bad, same goes to a value with a missing end quote.

This happens because the error is not detected until the end of the
line, when line number is already increased. Fix this by decreasing
line number by one for these cases.

Signed-off-by: Martin Stenberg <martin@gnutiken.se>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

config.c

@@ -135,8 +135,10 @@ static char *parse_value(void)
 	for (;;) {
 		int c = get_next_char();
 		if (c == '\n') {
-			if (quote)
+			if (quote) {
+				cf->linenr--;
 				return NULL;
+			}
 			return cf->value.buf;
 		}
 		if (comment)
@@ -226,7 +228,7 @@ static int get_extended_base_var(char *name, int baselen, int c)
 {
 	do {
 		if (c == '\n')
-			return -1;
+			goto error_incomplete_line;
 		c = get_next_char();
 	} while (isspace(c));
 
@@ -238,13 +240,13 @@ static int get_extended_base_var(char *name, int baselen, int c)
 	for (;;) {
 		int c = get_next_char();
 		if (c == '\n')
-			return -1;
+			goto error_incomplete_line;
 		if (c == '"')
 			break;
 		if (c == '\\') {
 			c = get_next_char();
 			if (c == '\n')
-				return -1;
+				goto error_incomplete_line;
 		}
 		name[baselen++] = c;
 		if (baselen > MAXNAME / 2)
@@ -255,6 +257,9 @@ static int get_extended_base_var(char *name, int baselen, int c)
 	if (get_next_char() != ']')
 		return -1;
 	return baselen;
+error_incomplete_line:
+	cf->linenr--;
+	return -1;
 }
 
 static int get_base_var(char *name)

t/t1300-repo-config.sh

@@ -928,4 +928,35 @@ test_expect_success 'git -c complains about empty key and value' '
 	test_must_fail git -c "" rev-parse
 '
 
+# malformed configuration files
+test_expect_success 'barf on syntax error' '
+	cat >.git/config <<-\EOF &&
+	# broken section line
+	[section]
+	key garbage
+	EOF
+	test_must_fail git config --get section.key >actual 2>error &&
+	grep " line 3 " error
+'
+
+test_expect_success 'barf on incomplete section header' '
+	cat >.git/config <<-\EOF &&
+	# broken section line
+	[section
+	key = value
+	EOF
+	test_must_fail git config --get section.key >actual 2>error &&
+	grep " line 2 " error
+'
+
+test_expect_success 'barf on incomplete string' '
+	cat >.git/config <<-\EOF &&
+	# broken section line
+	[section]
+	key = "value string
+	EOF
+	test_must_fail git config --get section.key >actual 2>error &&
+	grep " line 3 " error
+'
+
 test_done