promises can be settled with another promise

mojolicious · Jan 31, 2018 · 53615cb · 53615cb
1 parent dde6b9e
commit 53615cb
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Showing 3 changed files with 26 additions and 5 deletions.
diff --git a/Changes b/Changes
@@ -1,5 +1,6 @@
 
-7.62  2018-01-15
+7.62  2018-02-01
+  - Fixed a promise resolution bug in Mojo::Promise.
 
 7.61  2018-01-08
   - Increased default upgrade_timeout from 60 to 180 seconds in

diff --git a/lib/Mojo/Promise.pm b/lib/Mojo/Promise.pm
@@ -109,7 +109,13 @@ sub _finally {
 
 sub _settle {
   my ($self, $status) = (shift, shift);
+
+  $_[0]->then(sub { $self->resolve(@_); () }, sub { $self->reject(@_); () })
+    and return $self
+    if blessed $_[0] && $_[0]->can('then');
+
   return $self if $self->{result};
+
   @{$self}{qw(result status)} = ([@_], $status);
   $self->_defer;
   return $self;
@@ -122,11 +128,8 @@ sub _then {
 
   my @res;
   return $new->reject($@) unless eval { @res = $cb->(@result); 1 };
+  return $new->resolve(@res);
 
-  return $new->resolve(@res)
-    unless @res == 1 && blessed $res[0] && $res[0]->can('then');
-
-  $res[0]->then(sub { $new->resolve(@_); () }, sub { $new->reject(@_); () });
 }
 
 1;

diff --git a/t/mojo/promise.t b/t/mojo/promise.t
@@ -185,4 +185,21 @@ Mojo::IOLoop->one_tick;
 is_deeply \@results, [], 'promises not resolved';
 is_deeply \@errors, ['third'], 'promise rejected';
 
+# Settle with promise
+$promise  = Mojo::Promise->new->resolve('works');
+@results  = ();
+$promise2 = Mojo::Promise->new->resolve($promise)
+  ->then(sub { push @results, 'first', @_; @_ });
+$promise2->then(sub { push @results, 'second', @_ });
+Mojo::IOLoop->one_tick;
+is_deeply \@results, ['first', 'works', 'second', 'works'], 'promises resolved';
+$promise  = Mojo::Promise->new->reject('works too');
+@errors   = ();
+$promise2 = Mojo::Promise->new->reject($promise)
+  ->catch(sub { push @errors, 'first', @_; @_ });
+$promise2->then(sub { push @errors, 'second', @_ });
+Mojo::IOLoop->one_tick;
+is_deeply \@errors, ['first', 'works too', 'second', 'works too'],
+  'promises rejected';
+
 done_testing();