sequencer: notify user of --update-refs activity

When the user runs 'git rebase -i --update-refs', the end message still
says only

  Successfully rebased and updated <HEAD-ref>.

Update the sequencer to collect the successful (and unsuccessful) ref
updates due to the --update-refs option, so the end message now says

  Successfully rebased and updated <HEAD-ref>.
  Updated the following refs with --update-refs:
	refs/heads/first
	refs/heads/third
  Failed to update the following refs with --update-refs:
	refs/heads/second

To test this output, we need to be very careful to format the expected
error to drop the leading tab characters. Also, we need to be aware that
the verbose output from 'git rebase' is writing progress lines which
don't use traditional newlines but clear the line after every progress
item is complete. When opening the error file in an editor, these lines
are visible, but when looking at the diff in a terminal those lines
disappear because of the characters that delete the previous characters.
Use 'sed' to clear those progress lines and clear the tabs so we can get
an exact match on our expected output.

Reported-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer.c

@@ -4286,26 +4286,54 @@ static int do_update_ref(struct repository *r, const char *refname)
 	return 0;
 }
 
-static int do_update_refs(struct repository *r)
+static int do_update_refs(struct repository *r, int quiet)
 {
 	int res = 0;
 	struct string_list_item *item;
 	struct string_list refs_to_oids = STRING_LIST_INIT_DUP;
 	struct ref_store *refs = get_main_ref_store(r);
+	struct strbuf update_msg = STRBUF_INIT;
+	struct strbuf error_msg = STRBUF_INIT;
 
 	if ((res = sequencer_get_update_refs_state(r->gitdir, &refs_to_oids)))
 		return res;
 
 	for_each_string_list_item(item, &refs_to_oids) {
 		struct update_ref_record *rec = item->util;
+		int loop_res;
 
-		res |= refs_update_ref(refs, "rewritten during rebase",
-				       item->string,
-				       &rec->after, &rec->before,
-				       0, UPDATE_REFS_MSG_ON_ERR);
+		loop_res = refs_update_ref(refs, "rewritten during rebase",
+					   item->string,
+					   &rec->after, &rec->before,
+					   0, UPDATE_REFS_MSG_ON_ERR);
+		res |= loop_res;
+
+		if (quiet)
+			continue;
+
+		if (loop_res)
+			strbuf_addf(&error_msg, "\t%s\n", item->string);
+		else
+			strbuf_addf(&update_msg, "\t%s\n", item->string);
+	}
+
+	if (!quiet &&
+	    (update_msg.len || error_msg.len)) {
+		fprintf(stderr,
+			_("Updated the following refs with %s:\n%s"),
+			"--update-refs",
+			update_msg.buf);
+
+		if (res)
+			fprintf(stderr,
+				_("Failed to update the following refs with %s:\n%s"),
+				"--update-refs",
+				error_msg.buf);
 	}
 
 	string_list_clear(&refs_to_oids, 1);
+	strbuf_release(&update_msg);
+	strbuf_release(&error_msg);
 	return res;
 }
 
@@ -4826,7 +4854,7 @@ cleanup_head_ref:
 		strbuf_release(&buf);
 		strbuf_release(&head_ref);
 
-		if (do_update_refs(r))
+		if (do_update_refs(r, opts->quiet))
 			return -1;
 	}
 

t/t3404-rebase-interactive.sh

@@ -1840,12 +1840,26 @@ test_expect_success '--update-refs updates refs correctly' '
 	test_commit extra2 fileX &&
 	git commit --amend --fixup=L &&
 
-	git rebase -i --autosquash --update-refs primary &&
+	git rebase -i --autosquash --update-refs primary 2>err &&
 
 	test_cmp_rev HEAD~3 refs/heads/first &&
 	test_cmp_rev HEAD~3 refs/heads/second &&
 	test_cmp_rev HEAD~1 refs/heads/third &&
-	test_cmp_rev HEAD refs/heads/no-conflict-branch
+	test_cmp_rev HEAD refs/heads/no-conflict-branch &&
+
+	cat >expect <<-\EOF &&
+	Successfully rebased and updated refs/heads/update-refs.
+	Updated the following refs with --update-refs:
+		refs/heads/first
+		refs/heads/no-conflict-branch
+		refs/heads/second
+		refs/heads/third
+	EOF
+
+	# Clear "Rebasing (X/Y)" progress lines and drop leading tabs.
+	sed -e "s/Rebasing.*Successfully/Successfully/g" -e "s/^\t//g" \
+		<err >err.trimmed &&
+	test_cmp expect err.trimmed
 '
 
 test_expect_success 'respect user edits to update-ref steps' '
@@ -1983,8 +1997,23 @@ test_expect_success '--update-refs: check failed ref update' '
 	# the lock in the update-refs file.
 	git rev-parse third >.git/refs/heads/second &&
 
-	git rebase --continue 2>err &&
-	grep "update_ref failed for ref '\''refs/heads/second'\''" err
+	test_must_fail git rebase --continue 2>err &&
+	grep "update_ref failed for ref '\''refs/heads/second'\''" err &&
+
+	cat >expect <<-\EOF &&
+	Updated the following refs with --update-refs:
+		refs/heads/first
+		refs/heads/no-conflict-branch
+		refs/heads/third
+	Failed to update the following refs with --update-refs:
+		refs/heads/second
+	EOF
+
+	# Clear "Rebasing (X/Y)" progress lines and drop leading tabs.
+	tail -n 6 err >err.last &&
+	sed -e "s/Rebasing.*Successfully/Successfully/g" -e "s/^\t//g" \
+		<err.last >err.trimmed &&
+	test_cmp expect err.trimmed
 '
 
 # This must be the last test in this file