Merge branch 'jk/shortlog-tolerate-broken-commit' into maint

"git shortlog" used to choke and die when there is a malformed commit
(e.g. missing authors); it now simply ignore such a commit and keeps
going.

* jk/shortlog-tolerate-broken-commit:
  shortlog: ignore commits with missing authors

builtin/shortlog.c

@@ -127,9 +127,11 @@ void shortlog_add_commit(struct shortlog *log, struct commit *commit)
 			author = buffer + 7;
 		buffer = eol;
 	}
-	if (!author)
-		die(_("Missing author: %s"),
+	if (!author) {
+		warning(_("Missing author: %s"),
 		    sha1_to_hex(commit->object.sha1));
+		return;
+	}
 	if (log->user_format) {
 		struct pretty_print_context ctx = {0};
 		ctx.fmt = CMIT_FMT_USERFORMAT;

t/t4201-shortlog.sh

@@ -172,4 +172,20 @@ test_expect_success 'shortlog encoding' '
 	git shortlog HEAD~2.. > out &&
 test_cmp expect out'
 
+test_expect_success 'shortlog ignores commits with missing authors' '
+	git commit --allow-empty -m normal &&
+	git commit --allow-empty -m soon-to-be-broken &&
+	git cat-file commit HEAD >commit.tmp &&
+	sed "/^author/d" commit.tmp >broken.tmp &&
+	commit=$(git hash-object -w -t commit --stdin <broken.tmp) &&
+	git update-ref HEAD $commit &&
+	cat >expect <<-\EOF &&
+	A U Thor (1):
+	      normal
+
+	EOF
+	git shortlog HEAD~2.. >actual &&
+	test_cmp expect actual
+'
+
 test_done