config: support values longer than 1023 bytes

parse_value in config.c has a static buffer of 1024 bytes that it
parse the value into. This can sometimes be a problem when a
config file contains very long values.

It's particularly amusing that git-config already is able to write
such files, so it should probably be able to read them as well.

Fix this by using a strbuf instead of a fixed-size buffer.
Signed-off-by: NErik Faye-Lund <kusmabite@gmail.com>
Acked-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

config.c

@@ -46,23 +46,21 @@ static int get_next_char(void)
 
 static char *parse_value(void)
 {
-	static char value[1024];
-	int quote = 0, comment = 0, len = 0, space = 0;
+	static struct strbuf value = STRBUF_INIT;
+	int quote = 0, comment = 0, space = 0;
 
+	strbuf_reset(&value);
 	for (;;) {
 		int c = get_next_char();
-		if (len >= sizeof(value) - 1)
-			return NULL;
 		if (c == '\n') {
 			if (quote)
 				return NULL;
-			value[len] = 0;
-			return value;
+			return value.buf;
 		}
 		if (comment)
 			continue;
 		if (isspace(c) && !quote) {
-			if (len)
+			if (value.len)
 				space++;
 			continue;
 		}
@@ -73,7 +71,7 @@ static char *parse_value(void)
 			}
 		}
 		for (; space; space--)
-			value[len++] = ' ';
+			strbuf_addch(&value, ' ');
 		if (c == '\\') {
 			c = get_next_char();
 			switch (c) {
@@ -95,14 +93,14 @@ static char *parse_value(void)
 			default:
 				return NULL;
 			}
-			value[len++] = c;
+			strbuf_addch(&value, c);
 			continue;
 		}
 		if (c == '"') {
 			quote = 1-quote;
 			continue;
 		}
-		value[len++] = c;
+		strbuf_addch(&value, c);
 	}
 }
 

t/t1303-wacky-config.sh

@@ -44,7 +44,7 @@ LONG_VALUE=$(printf "x%01021dx a" 7)
 test_expect_success 'do not crash on special long config line' '
 	setup &&
 	git config section.key "$LONG_VALUE" &&
-	check section.key "fatal: bad config file line 2 in .git/config"
+	check section.key "$LONG_VALUE"
 '
 
 test_done