Handle missing Remote Config parameter groups

Author: jeromegamez

CHANGELOG.md

@@ -9,6 +9,11 @@ Please update your remote URL if you have forked or cloned the repository.
 
 ## Unreleased
 
+## Remote Config
+
+* Fixed retrieving templates containing missing parameter groups 
+  ([#1133](https://github.com/beste/firebase-php/pull/1133)).
+
 ## Messaging
 
 * FCM `403 PERMISSION_DENIED` responses with the error code `SENDER_ID_MISMATCH` are now

src/RemoteConfig/ParameterGroup.php

@@ -11,7 +11,7 @@
  *
  * @phpstan-type RemoteConfigParameterGroupShape array{
  *     description?: string|null,
- *     parameters: array<non-empty-string, RemoteConfigParameterShape>}
+ *     parameters?: array<non-empty-string, RemoteConfigParameterShape>}
  */
 final class ParameterGroup implements JsonSerializable
 {

src/RemoteConfig/Template.php

@@ -266,7 +266,7 @@ private static function buildParameterGroup(string $name, array $parameterGroupD
             ->withDescription($parameterGroupData['description'] ?? '')
         ;
 
-        foreach ($parameterGroupData['parameters'] as $parameterName => $parameterData) {
+        foreach (($parameterGroupData['parameters'] ?? []) as $parameterName => $parameterData) {
             $group = $group->withParameter(self::buildParameter($parameterName, $parameterData));
         }
 

tests/Unit/RemoteConfig/TemplateTest.php

@@ -125,6 +125,16 @@ public function testParameterGroupsCanBeRemoved(): void
         $this->assertEmpty($template->parameterGroups());
     }
 
+    /**
+     * @see https://github.com/beste/firebase-php/issues/1132
+     */
+    public function testEmptyParameterGroupsCanBeImported(): void
+    {
+        $template = Template::fromArray(['parameterGroups' => ['empty' => []]]);
+
+        $this->assertSame([], $template->parameterGroups()['empty']->parameters());
+    }
+
     public function testPersonalizationValuesAreImportedInDefaultValues(): void
     {
         $data = [