mailmap: always return a plain mail address from map_user()

The callers of map_user() give email and name to it, and expect to get the
up-to-date email and/or name to be used in their output. The function
rewrites the given buffers in place. To optimize the majority of cases,
the function returns 0 when it did not do anything, and it returns 1 when
the caller should use the updated contents.

The 'email' input to the function is terminated by '>' or a NUL (whichever
comes first) for historical reasons, but when a rewrite happens, the value
is replaced with the mailbox inside the <> pair.  However, it failed to
meet this expectation when it only rewrote the name part without rewriting
the email part, and the email in the input was terminated by '>'.

This causes an extra '>' to appear in the output of "blame -e", because the
caller does send in '>'-terminated email, and when the function returned 1
to tell it that rewriting happened, it appends '>' that is necessary when
the email part was rewritten.

The patch looks bigger than it actually is, because this change makes a
variable that points at the end of the email part in the input 'p' live
much longer than it used to, deserving a more descriptive name.

Noticed and diagnosed by Felipe Contreras and Jeff King.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/mailmap.c b/mailmap.c
index 8c3196c7d76ff90e90a9fb4ff569aff6a429861a..47aa41924507f7603aab5e35abb51b3956a33dad 100644 (file)
--- a/mailmap.c
+++ b/mailmap.c
@@ -190,27 +190,27 @@ void clear_mailmap(struct string_list *map)
 int map_user(struct string_list *map,
             char *email, int maxlen_email, char *name, int maxlen_name)
 {
-       char *p;
+       char *end_of_email;
        struct string_list_item *item;
        struct mailmap_entry *me;
        char buf[1024], *mailbuf;
        int i;
 
        /* figure out space requirement for email */
-       p = strchr(email, '>');
-       if (!p) {
+       end_of_email = strchr(email, '>');
+       if (!end_of_email) {
                /* email passed in might not be wrapped in <>, but end with a \0 */
-               p = memchr(email, '\0', maxlen_email);
-               if (!p)
+               end_of_email = memchr(email, '\0', maxlen_email);
+               if (!end_of_email)
                        return 0;
        }
-       if (p - email + 1 < sizeof(buf))
+       if (end_of_email - email + 1 < sizeof(buf))
                mailbuf = buf;
        else
-               mailbuf = xmalloc(p - email + 1);
+               mailbuf = xmalloc(end_of_email - email + 1);
 
        /* downcase the email address */
-       for (i = 0; i < p - email; i++)
+       for (i = 0; i < end_of_email - email; i++)
                mailbuf[i] = tolower(email[i]);
        mailbuf[i] = 0;
 
@@ -236,6 +236,8 @@ int map_user(struct string_list *map,
                }
                if (maxlen_email && mi->email)
                        strlcpy(email, mi->email, maxlen_email);
+               else
+                       *end_of_email = '\0';
                if (maxlen_name && mi->name)
                        strlcpy(name, mi->name, maxlen_name);
                debug_mm("map_user:  to '%s' <%s>\n", name, mi->email ? mi->email : "");