diff --git a/degesch.c b/degesch.c
index 71f2931..049e9c8 100644
--- a/degesch.c
+++ b/degesch.c
@@ -1591,12 +1591,14 @@ static struct ispect_field g_buffer_ispect[] =
 };
 
 static struct buffer *
-buffer_new (struct input *input)
+buffer_new (struct input *input, enum buffer_type type, char *name)
 {
 	struct buffer *self = xcalloc (1, sizeof *self);
 	self->ref_count = 1;
 	self->input = input;
 	self->input_data = CALL (input, buffer_new);
+	self->type = type;
+	self->name = name;
 	return self;
 }
 
@@ -4446,9 +4448,8 @@ buffer_remove_safe (struct app_context *ctx, struct buffer *buffer)
 static void
 init_global_buffer (struct app_context *ctx)
 {
-	struct buffer *global = ctx->global_buffer = buffer_new (ctx->input);
-	global->type = BUFFER_GLOBAL;
-	global->name = xstrdup (PROGRAM_NAME);
+	struct buffer *global = ctx->global_buffer =
+		buffer_new (ctx->input, BUFFER_GLOBAL, xstrdup (PROGRAM_NAME));
 
 	buffer_add (ctx, global);
 	buffer_activate (ctx, global);
@@ -4456,6 +4457,19 @@ init_global_buffer (struct app_context *ctx)
 
 // --- Users, channels ---------------------------------------------------------
 
+static char *
+irc_make_buffer_name (struct server *s, const char *target)
+{
+	if (!target)
+		return xstrdup (s->name);
+
+	// XXX: this may be able to trigger the uniqueness assertion with non-UTF-8
+	char *target_utf8 = irc_to_utf8 (target);
+	char *result = xstrdup_printf ("%s.%s", s->name, target_utf8);
+	free (target_utf8);
+	return result;
+}
+
 static void
 irc_user_on_destroy (void *object, void *user_data)
 {
@@ -4495,11 +4509,8 @@ irc_get_or_make_user_buffer (struct server *s, const char *nickname)
 	struct user *user = irc_get_or_make_user (s, nickname);
 
 	// Open a new buffer for the user
-	buffer = buffer_new (s->ctx->input);
-	buffer->type = BUFFER_PM;
-	char *nickname_utf8 = irc_to_utf8 (nickname);
-	buffer->name = xstrdup_printf ("%s.%s", s->name, nickname_utf8);
-	free (nickname_utf8);
+	buffer = buffer_new (s->ctx->input,
+		BUFFER_PM, irc_make_buffer_name (s, nickname));
 	buffer->server = s;
 	buffer->user = user;
 	str_map_set (&s->irc_buffer_map, user->nickname, buffer);
@@ -6644,11 +6655,8 @@ irc_handle_join (struct server *s, const struct irc_message *msg)
 		if (!irc_is_this_us (s, msg->prefix))
 			return;
 
-		buffer = buffer_new (s->ctx->input);
-		buffer->type = BUFFER_CHANNEL;
-		char *channel_name_utf8 = irc_to_utf8 (channel_name);
-		buffer->name = xstrdup_printf ("%s.%s", s->name, channel_name_utf8);
-		free (channel_name_utf8);
+		buffer = buffer_new (s->ctx->input,
+			BUFFER_CHANNEL, irc_make_buffer_name (s, channel_name));
 		buffer->server = s;
 		buffer->channel = channel =
 			irc_make_channel (s, xstrdup (channel_name));
@@ -8318,9 +8326,8 @@ server_add (struct app_context *ctx,
 	s->config = subtree;
 
 	// Add a buffer and activate it
-	struct buffer *buffer = s->buffer = buffer_new (ctx->input);
-	buffer->type = BUFFER_SERVER;
-	buffer->name = xstrdup (s->name);
+	struct buffer *buffer = s->buffer = buffer_new (ctx->input,
+		BUFFER_SERVER, irc_make_buffer_name (s, NULL));
 	buffer->server = s;
 
 	buffer_add (ctx, buffer);