Retry aliases query (#1056)

Also, switch to the stable endpoint, now that Synapse supports it.

Fixes #1055

run-tests.pl

@@ -415,26 +415,45 @@ sub delay
    $loop->delay_future( after => $secs * $TIMEOUT_FACTOR );
 }
 
-# Handy utility wrapper around Future::Utils::try_repeat_until_success which
-# includes a delay on retry (and logs the reason for failure)
-sub retry_until_success(&)
+
+# Retries a code block until it returns a successful Future.
+#
+# Includes a delay between each call, and logs the reason for failure.
+#
+# The code block is called with the iteration number.
+#
+# Example:
+#
+#   retry_until_success {
+#      my ( $iter ) = @_;
+#      ...
+#   }, max_iterations => 20,
+#      initial_delay => 0.01;
+#
+# Will fail if the code block fails `max_iterations` (default 7) times.
+#
+sub retry_until_success(&%)
 {
-   my ( $code ) = @_;
+   my ( $code, %params ) = @_;
 
-   my $delay = 0.1;
+   my $delay = $params{initial_delay} // 0.1;
+
+   # 7 iterations means a total delay of
+   #  0.1 * (1 + 1.5 + 1.5^2 + ... + 1.5^5 )
+   #    =~ 2.0 seconds.
+   my $max_iter = $params{max_iterations} // 7;
    my $iter = 0;
 
    try_repeat {
-      ( $iter++ ?
-            delay( $delay *= 1.5 ) :
-            Future->done )
-         ->then( $code )
-         ->on_fail( sub {
-            my ( $exc ) = @_;
-            chomp $exc;
-            log_if_fail("Iteration $iter: not ready yet: $exc");
-         });
-   }  until => sub { !$_[0]->failure };
+      ( $iter ? delay( $delay *= 1.5 ) : Future->done )
+      ->then( sub {
+         Future->call( $code, $iter++ );
+      })->on_fail( sub {
+         my ( $exc ) = @_;
+         chomp $exc;
+         log_if_fail("Iteration $iter++: not ready yet: $exc");
+      });
+   } until => sub { $iter > $max_iter || !$_[0]->failure };
 }
 
 # Another wrapper which repeats (with delay) until the block returns a true

tests/10apidoc/32room-alias.pl

@@ -63,11 +63,11 @@
          do_request_json_for(
             $user,
             method => "GET",
-            uri => "/unstable/org.matrix.msc2432/rooms/$room_id/aliases",
+            uri => "/r0/rooms/$room_id/aliases",
          );
       })->then( sub {
          my ( $res ) = @_;
-         log_if_fail "response from /aliases", $res;
+         log_if_fail "response from /aliases before change:", $res;
 
          assert_json_keys( $res, qw( aliases ));
          assert_json_empty_list( $res->{aliases} );
@@ -79,19 +79,25 @@
             uri    => "/r0/directory/room/$room_alias",
             content => { room_id => $room_id },
          );
-      })->then( sub {
-         # ... and recheck
-         do_request_json_for(
-            $user,
-            method => "GET",
-            uri => "/unstable/org.matrix.msc2432/rooms/$room_id/aliases",
-         );
       })->then( sub {
          my ( $res ) = @_;
-         log_if_fail "response from /aliases", $res;
-
-         assert_json_keys( $res, qw( aliases ));
-         assert_deeply_eq($res->{aliases}, [ $room_alias ]);
-         Future->done;
+         log_if_fail "response from PUT /directory:", $res;
+
+         # ... and recheck. Might need to try this a few times while the caches
+         # get flushed.
+         retry_until_success {
+            my ( $iter ) = @_;
+            return do_request_json_for(
+               $user,
+               method => "GET",
+               uri => "/r0/rooms/$room_id/aliases",
+            )->then( sub {
+               my ( $res ) = @_;
+               log_if_fail "$iter: response from /aliases", $res;
+               assert_json_keys( $res, qw( aliases ));
+               assert_deeply_eq($res->{aliases}, [ $room_alias ]);
+               Future->done;
+            });
+         }
       });
    };