Make "pretty" commit logs always show merge information

Otherwise the "git log" information doesn't tell enough to make sense of
a merge.

I'll need to add some parent information for regular entries too, I
think, but the merge is more important.

diff --git a/commit.c b/commit.c
index 9fa03ef..60047a0 100644 (file)
--- a/commit.c
+++ b/commit.c
@@ -222,10 +222,29 @@ static int is_empty_line(const char *line, int len)
        return !len;
 }
 
+static int add_parent_info(enum cmit_fmt fmt, char *buf, const char *line, int parents)
+{
+       int offset = 0;
+       switch (parents) {
+       case 1:
+               break;
+       case 2:
+               /* Go back to the previous line: 40 characters of previous parent, and one '\n' */
+               offset = sprintf(buf, "Merge: %.40s\n", line-41);
+               /* Fallthrough */
+       default:
+               /* Replace the previous '\n' with a space */
+               buf[offset-1] = ' ';
+               offset += sprintf(buf + offset, "%.40s\n", line+7);
+       }
+       return offset;
+}
+
 unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned long len, char *buf, unsigned long space)
 {
        int hdr = 1, body = 0;
        unsigned long offset = 0;
+       int parents = 0;
 
        for (;;) {
                const char *line = msg;
@@ -257,6 +276,11 @@ unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned l
                                offset += linelen;
                                continue;
                        }
+                       if (!memcmp(line, "parent ", 7)) {
+                               if (linelen != 48)
+                                       die("bad parent line in commit");
+                               offset += add_parent_info(fmt, buf + offset, line, ++parents);
+                       }
                        if (!memcmp(line, "author ", 7))
                                offset += add_author_info(fmt, buf + offset, line, linelen);
                        continue;