config.c:store_write_pair(): don't read the byte before a malloc'd buffer.

Signed-off-by: Jim Meyering <meyering@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/config.c b/config.c
index 56e99fc0f4750174299303b27237737e09549933..914cfce855d83d8a3404f315fd537f2f46da9d41 100644 (file)
--- a/config.c
+++ b/config.c
@@ -630,13 +630,19 @@ static int store_write_pair(int fd, const char* key, const char* value)
        int length = strlen(key+store.baselen+1);
        int quote = 0;
 
-       /* Check to see if the value needs to be quoted. */
+       /*
+        * Check to see if the value needs to be surrounded with a dq pair.
+        * Note that problematic characters are always backslash-quoted; this
+        * check is about not losing leading or trailing SP and strings that
+        * follow beginning-of-comment characters (i.e. ';' and '#') by the
+        * configuration parser.
+        */
        if (value[0] == ' ')
                quote = 1;
        for (i = 0; value[i]; i++)
                if (value[i] == ';' || value[i] == '#')
                        quote = 1;
-       if (value[i-1] == ' ')
+       if (i && value[i-1] == ' ')
                quote = 1;
 
        if (write_in_full(fd, "\t", 1) != 1 ||