Re: [PATCH v3 4/4] submodule: port submodule subcommand 'summary' from shell to C

(A few miniscule things I noticed that are irrelevant to the code
structure discussion).

+static char* verify_submodule_committish(const char *sm_path,

Style: in C, asterisk sticks to the identifier, not type, i.e.

    static char *verify_submodule_committish(const char *sm_path, ...);

+static void print_submodule_summary(struct summary_cb *info, char* errmsg,

Likewise; "char *errmsg".

+static void generate_submodule_summary(struct summary_cb *info,
+				       struct module_cb *p)
+{
+	char *displaypath, *src_abbrev, *dst_abbrev;
+	int missing_src = 0, missing_dst = 0;
+	char *errmsg = NULL;
+	int total_commits = -1;
+
+	if (!info->cached && oideq(&p->oid_dst, &null_oid)) {
+		if (S_ISGITLINK(p->mod_dst)) {
+...
+		} else {
+			/* for a submodule removal (mode:0000000), don't warn */
+			if (p->mod_dst)
+				warning(_("unexpected mode %d\n"), p->mod_dst);
+		}
+	}

Nobody can read mode bits written in decimal.  Use "%o" instead,
perhaps?

Thanks.