PostHog · dustinbyrne · Dec 17, 2025 · Dec 16, 2025 · Dec 16, 2025
diff --git a/lib/Client.php b/lib/Client.php
@@ -149,27 +149,30 @@ public function capture(array $message)
             $message["properties"]['$groups'] = $message['$groups'];
         }
 
-        $extraProperties = [];
-        $flags = [];
         if (array_key_exists("send_feature_flags", $message) && $message["send_feature_flags"]) {
-            $flags = $this->fetchFeatureVariants($message["distinct_id"], $message["groups"]);
-        } elseif (count($this->featureFlags) != 0) {
-            # Local evaluation is enabled, flags are loaded, so try and get all flags we can without going to the server
-            $flags = $this->getAllFlags($message["distinct_id"], $message["groups"], [], [], true);
-        }
+            $extraProperties = [];
+            $flags = [];
+
+            if (count($this->featureFlags) != 0) {
+                # Local evaluation is enabled, flags are loaded, so try and get all flags we can without going to the server
+                $flags = $this->getAllFlags($message["distinct_id"], $message["groups"], [], [], true);
+            } else {
+                $flags = $this->fetchFeatureVariants($message["distinct_id"], $message["groups"]);
+            }
 
-        // Add all feature variants to event
-        foreach ($flags as $flagKey => $flagValue) {
-            $extraProperties[sprintf('$feature/%s', $flagKey)] = $flagValue;
-        }
+            // Add all feature variants to event
+            foreach ($flags as $flagKey => $flagValue) {
+                $extraProperties[sprintf('$feature/%s', $flagKey)] = $flagValue;
+            }
+            // Add all feature flag keys that aren't false to $active_feature_flags
+            // decide v2 does this automatically, but we need it for when we upgrade to v3
+            $extraProperties['$active_feature_flags'] = array_keys(array_filter($flags, function ($flagValue) {
+                return $flagValue !== false;
+            }));
 
-        // Add all feature flag keys that aren't false to $active_feature_flags
-        // decide v2 does this automatically, but we need it for when we upgrade to v3
-        $extraProperties['$active_feature_flags'] = array_keys(array_filter($flags, function ($flagValue) {
-            return $flagValue !== false;
-        }));
+            $message["properties"] = array_merge($extraProperties, $message["properties"]);
+        }
 
-        $message["properties"] = array_merge($extraProperties, $message["properties"]);
 
         return $this->consumer->capture($message);
     }

diff --git a/test/FeatureFlagLocalEvaluationTest.php b/test/FeatureFlagLocalEvaluationTest.php
@@ -1367,7 +1367,7 @@ public function testSimpleFlag()
                     ),
                     1 => array(
                         "path" => "/batch/",
-                        'payload' => '{"batch":[{"properties":{"$feature\/simple-flag":true,"$active_feature_flags":["simple-flag"],"$feature_flag":"simple-flag","$feature_flag_response":true,"$lib":"posthog-php","$lib_version":"' . PostHog::VERSION . '","$lib_consumer":"LibCurl","$groups":[]},"distinct_id":"some-distinct-id","event":"$feature_flag_called","$groups":[],"library":"posthog-php","library_version":"' . PostHog::VERSION . '","library_consumer":"LibCurl","groups":[],"timestamp":"2022-05-01T00:00:00+00:00","type":"capture"}],"api_key":"random_key"}',
+                        'payload' => '{"batch":[{"properties":{"$feature_flag":"simple-flag","$feature_flag_response":true,"$lib":"posthog-php","$lib_version":"' . PostHog::VERSION . '","$lib_consumer":"LibCurl","$groups":[]},"distinct_id":"some-distinct-id","event":"$feature_flag_called","$groups":[],"library":"posthog-php","library_version":"' . PostHog::VERSION . '","library_consumer":"LibCurl","groups":[],"timestamp":"2022-05-01T00:00:00+00:00","type":"capture"}],"api_key":"random_key"}',
                         "extraHeaders" => array(0 => 'User-Agent: posthog-php/' . PostHog::VERSION),
                         "requestOptions" => array('shouldVerify' => true),
                     ),

diff --git a/test/FeatureFlagTest.php b/test/FeatureFlagTest.php
@@ -96,7 +96,7 @@ public function testIsFeatureEnabledCapturesFeatureFlagCalledEventWithAdditional
                     ),
                 1 => array(
                     "path" => "/batch/",
-                    "payload" => '{"batch":[{"properties":{"$active_feature_flags":[],"$feature_flag":"simple-test","$feature_flag_response":true,"$feature_flag_request_id":"98487c8a-287a-4451-a085-299cd76228dd","$feature_flag_id":6,"$feature_flag_version":1,"$feature_flag_reason":"Matched condition set 1","$lib":"posthog-php","$lib_version":"' . PostHog::VERSION . '","$lib_consumer":"LibCurl","$groups":[]},"distinct_id":"user-id","event":"$feature_flag_called","$groups":[],"library":"posthog-php","library_version":"' . PostHog::VERSION . '","library_consumer":"LibCurl","groups":[],"timestamp":"2022-05-01T00:00:00+00:00","type":"capture"}],"api_key":"random_key"}',
+                    "payload" => '{"batch":[{"properties":{"$feature_flag":"simple-test","$feature_flag_response":true,"$feature_flag_request_id":"98487c8a-287a-4451-a085-299cd76228dd","$feature_flag_id":6,"$feature_flag_version":1,"$feature_flag_reason":"Matched condition set 1","$lib":"posthog-php","$lib_version":"' . PostHog::VERSION . '","$lib_consumer":"LibCurl","$groups":[]},"distinct_id":"user-id","event":"$feature_flag_called","$groups":[],"library":"posthog-php","library_version":"' . PostHog::VERSION . '","library_consumer":"LibCurl","groups":[],"timestamp":"2022-05-01T00:00:00+00:00","type":"capture"}],"api_key":"random_key"}',
                     "extraHeaders" => array(0 => 'User-Agent: posthog-php/' . PostHog::VERSION),
                     "requestOptions" => array('shouldVerify' => true),
                     ),
@@ -178,7 +178,7 @@ public function testGetFeatureFlagCapturesFeatureFlagCalledEventWithAdditionalMe
                 ),
                 1 => array(
                     "path" => "/batch/",
-                    "payload" => '{"batch":[{"properties":{"$active_feature_flags":[],"$feature_flag":"multivariate-test","$feature_flag_response":"variant-value","$feature_flag_request_id":"98487c8a-287a-4451-a085-299cd76228dd","$feature_flag_id":7,"$feature_flag_version":3,"$feature_flag_reason":"Matched condition set 2","$lib":"posthog-php","$lib_version":"' . PostHog::VERSION . '","$lib_consumer":"LibCurl","$groups":[]},"distinct_id":"user-id","event":"$feature_flag_called","$groups":[],"library":"posthog-php","library_version":"' . PostHog::VERSION . '","library_consumer":"LibCurl","groups":[],"timestamp":"2022-05-01T00:00:00+00:00","type":"capture"}],"api_key":"random_key"}',
+                    "payload" => '{"batch":[{"properties":{"$feature_flag":"multivariate-test","$feature_flag_response":"variant-value","$feature_flag_request_id":"98487c8a-287a-4451-a085-299cd76228dd","$feature_flag_id":7,"$feature_flag_version":3,"$feature_flag_reason":"Matched condition set 2","$lib":"posthog-php","$lib_version":"' . PostHog::VERSION . '","$lib_consumer":"LibCurl","$groups":[]},"distinct_id":"user-id","event":"$feature_flag_called","$groups":[],"library":"posthog-php","library_version":"' . PostHog::VERSION . '","library_consumer":"LibCurl","groups":[],"timestamp":"2022-05-01T00:00:00+00:00","type":"capture"}],"api_key":"random_key"}',
                     "extraHeaders" => array(0 => 'User-Agent: posthog-php/' . PostHog::VERSION),
                     "requestOptions" => array('shouldVerify' => true),
                 ),

diff --git a/test/PostHogTest.php b/test/PostHogTest.php
@@ -117,28 +117,22 @@ public function testCaptureWithSendFeatureFlagsOption(): void
                         "requestOptions" => array("includeEtag" => true),
                     ),
                     1 => array (
-                        "path" => "/flags/?v=2",
-                        "payload" => sprintf('{"api_key":"%s","distinct_id":"john"}', self::FAKE_API_KEY),
-                        "extraHeaders" => array(0 => 'User-Agent: posthog-php/' . PostHog::VERSION),
-                        "requestOptions" => array("timeout" => 1234, "shouldRetry" => false),
-                    ),
-                    2 => array (
                         "path" => "/batch/",
-                        "payload" => '{"batch":[{"event":"Module PHP Event","send_feature_flags":true,"properties":{"$feature\/simpleFlag":true,"$feature\/having_fun":false,"$feature\/enabled-flag":true,"$feature\/disabled-flag":false,"$feature\/multivariate-simple-test":"variant-simple-value","$feature\/simple-test":true,"$feature\/multivariate-test":"variant-value","$feature\/group-flag":"decide-fallback-value","$feature\/complex-flag":"decide-fallback-value","$feature\/beta-feature":"decide-fallback-value","$feature\/beta-feature2":"alakazam","$feature\/feature-1":"decide-fallback-value","$feature\/feature-2":"decide-fallback-value","$feature\/variant-1":"variant-1","$feature\/variant-3":"variant-3","$active_feature_flags":["simpleFlag","enabled-flag","multivariate-simple-test","simple-test","multivariate-test","group-flag","complex-flag","beta-feature","beta-feature2","feature-1","feature-2","variant-1","variant-3"],"$lib":"posthog-php","$lib_version":"' . PostHog::VERSION . '","$lib_consumer":"LibCurl"},"library":"posthog-php","library_version":"' . PostHog::VERSION . '","library_consumer":"LibCurl","distinct_id":"john","groups":[],"timestamp":"2022-05-01T00:00:00+00:00","type":"capture"}],"api_key":"random_key"}',
+                        "payload" => '{"batch":[{"event":"Module PHP Event","send_feature_flags":true,"properties":{"$feature\/true-flag":true,"$active_feature_flags":["true-flag"],"$lib":"posthog-php","$lib_version":"' . PostHog::VERSION . '","$lib_consumer":"LibCurl"},"library":"posthog-php","library_version":"' . PostHog::VERSION . '","library_consumer":"LibCurl","distinct_id":"john","groups":[],"timestamp":"2022-05-01T00:00:00+00:00","type":"capture"}],"api_key":"random_key"}',
                         "extraHeaders" => array(0 => 'User-Agent: posthog-php/' . PostHog::VERSION),
                         "requestOptions" => array('shouldVerify' => true),
                     ),
                 )
             );
 
-            // check true-flag is not in captured event
+            // Verify only locally evaluated feature flags are included
             $this->assertEquals(
-                strpos($this->http_client->calls[2]["payload"], 'simpleFlag'),
-                true
+                strpos($this->http_client->calls[1]["payload"], 'simpleFlag'),
+                false
             );
             $this->assertEquals(
-                strpos($this->http_client->calls[2]["payload"], 'true-flag'),
-                false
+                strpos($this->http_client->calls[1]["payload"], 'true-flag'),
+                true
             );
         });
     }
@@ -162,7 +156,8 @@ public function testCaptureWithLocalSendFlags(): void
                     array (
                         "distinctId" => "john",
                         "event" => "Module PHP Event",
-                    )
+                        "send_feature_flags" => true
+                    ),
                 )
             );
 
@@ -179,7 +174,7 @@ public function testCaptureWithLocalSendFlags(): void
                     ),
                     1 => array (
                         "path" => "/batch/",
-                        "payload" => '{"batch":[{"event":"Module PHP Event","properties":{"$feature\/true-flag":true,"$active_feature_flags":["true-flag"],"$lib":"posthog-php","$lib_version":"' . PostHog::VERSION . '","$lib_consumer":"LibCurl"},"library":"posthog-php","library_version":"' . PostHog::VERSION . '","library_consumer":"LibCurl","distinct_id":"john","groups":[],"timestamp":"2022-05-01T00:00:00+00:00","type":"capture"}],"api_key":"random_key"}',
+                        "payload" => '{"batch":[{"event":"Module PHP Event","send_feature_flags":true,"properties":{"$feature\/true-flag":true,"$active_feature_flags":["true-flag"],"$lib":"posthog-php","$lib_version":"' . PostHog::VERSION . '","$lib_consumer":"LibCurl"},"library":"posthog-php","library_version":"' . PostHog::VERSION . '","library_consumer":"LibCurl","distinct_id":"john","groups":[],"timestamp":"2022-05-01T00:00:00+00:00","type":"capture"}],"api_key":"random_key"}',
                         "extraHeaders" => array(0 => 'User-Agent: posthog-php/' . PostHog::VERSION),
                         "requestOptions" => array('shouldVerify' => true),
                     ),
@@ -209,7 +204,8 @@ public function testCaptureWithLocalSendFlagsNoOverrides(): void
                         "event" => "Module PHP Event",
                         "properties" => array (
                             "\$feature/true-flag" => "random-override"
-                        )
+                        ),
+                        "send_feature_flags" => true
                     )
                 )
             );
@@ -228,7 +224,7 @@ public function testCaptureWithLocalSendFlagsNoOverrides(): void
                     ),
                     1 => array (
                         "path" => "/batch/",
-                        "payload" => '{"batch":[{"event":"Module PHP Event","properties":{"$feature\/true-flag":"random-override","$active_feature_flags":["true-flag"],"$lib":"posthog-php","$lib_version":"' . PostHog::VERSION . '","$lib_consumer":"LibCurl"},"library":"posthog-php","library_version":"' . PostHog::VERSION . '","library_consumer":"LibCurl","distinct_id":"john","groups":[],"timestamp":"2022-05-01T00:00:00+00:00","type":"capture"}],"api_key":"random_key"}',
+                        "payload" => '{"batch":[{"event":"Module PHP Event","properties":{"$feature\/true-flag":"random-override","$active_feature_flags":["true-flag"],"$lib":"posthog-php","$lib_version":"' . PostHog::VERSION . '","$lib_consumer":"LibCurl"},"send_feature_flags":true,"library":"posthog-php","library_version":"' . PostHog::VERSION . '","library_consumer":"LibCurl","distinct_id":"john","groups":[],"timestamp":"2022-05-01T00:00:00+00:00","type":"capture"}],"api_key":"random_key"}',
                         "extraHeaders" => array(0 => 'User-Agent: posthog-php/' . PostHog::VERSION),
                         "requestOptions" => array('shouldVerify' => true),
                     ),
@@ -467,4 +463,56 @@ public function testDefaultPropertiesGetAddedProperly(): void
             )
         );
     }
+
+    public function testCaptureWithSendFeatureFlagsFalse(): void
+    {
+        $this->http_client = new MockedHttpClient(host: "app.posthog.com", flagEndpointResponse: MockedResponses::LOCAL_EVALUATION_MULTIPLE_REQUEST);
+        $this->client = new Client(
+            self::FAKE_API_KEY,
+            [
+                "debug" => true,
+            ],
+            $this->http_client,
+            "test"
+        );
+        PostHog::init(null, null, $this->client);
+
+        ClockMock::executeAtFrozenDateTime(new \DateTime('2022-05-01'), function () {
+            $this->assertTrue(
+                PostHog::capture(
+                    array (
+                        "distinctId" => "john",
+                        "event" => "Module PHP Event",
+                        "send_feature_flags" => false
+                    )
+                )
+            );
+
+            PostHog::flush();
+
+            // When send_feature_flags is explicitly false, NO feature flags should be added
+            $this->assertEquals(
+                $this->http_client->calls,
+                array (
+                    0 => array (
+                        "path" => "/api/feature_flag/local_evaluation?send_cohorts&token=random_key",
+                        "payload" => null,
+                        "extraHeaders" => array(0 => 'User-Agent: posthog-php/' . PostHog::VERSION, 1 => 'Authorization: Bearer test'),
+                        "requestOptions" => array("includeEtag" => true),
+                    ),
+                    1 => array (
+                        "path" => "/batch/",
+                        "payload" => '{"batch":[{"event":"Module PHP Event","send_feature_flags":false,"properties":{"$lib":"posthog-php","$lib_version":"' . PostHog::VERSION . '","$lib_consumer":"LibCurl"},"library":"posthog-php","library_version":"' . PostHog::VERSION . '","library_consumer":"LibCurl","distinct_id":"john","groups":[],"timestamp":"2022-05-01T00:00:00+00:00","type":"capture"}],"api_key":"random_key"}',
+                        "extraHeaders" => array(0 => 'User-Agent: posthog-php/' . PostHog::VERSION),
+                        "requestOptions" => array('shouldVerify' => true),
+                    ),
+                )
+            );
+
+            // Verify NO feature flag properties were added
+            $payload = $this->http_client->calls[1]["payload"];
+            $this->assertStringNotContainsString('$feature/', $payload);
+            $this->assertStringNotContainsString('$active_feature_flags', $payload);
+        });
+    }
 }