fast-export: respect the possibly-overridden default branch name

When anonymizing commit history, we are careful to leave the branch name
of the default branch alone.

When the default branch name is overridden via the config or via the
environment variable, we will want `git fast-export` to use that
overridden name instead.

Signed-off-by: Johannes Schindelin <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: dscho

builtin/fast-export.c

@@ -515,13 +515,17 @@ static const char *anonymize_refname(const char *refname)
 	};
 	static struct hashmap refs;
 	static struct strbuf anon = STRBUF_INIT;
+	static char *default_branch_name;
 	int i;
 
 	/*
-	 * We also leave "master" as a special case, since it does not reveal
-	 * anything interesting.
+	 * We also leave the default branch name as a special case, since it
+	 * does not reveal anything interesting.
 	 */
-	if (!strcmp(refname, "refs/heads/master"))
+	if (!default_branch_name)
+		default_branch_name = git_default_branch_name(0);
+
+	if (!strcmp(refname, default_branch_name))
 		return refname;
 
 	strbuf_reset(&anon);