Merge pull request #16609 from emberjs/container-tracking

Add container leak tracking

packages/container/lib/container.js

@@ -6,6 +6,37 @@ import { OWNER, setOwner } from 'ember-owner';
 import { assign } from '@ember/polyfills';
 import { dictionary, HAS_NATIVE_PROXY } from 'ember-utils';
 
+let leakTracking, containers;
+if (DEBUG) {
+  // requires v8
+  // chrome --js-flags="--allow-natives-syntax --expose-gc"
+  // node --allow-natives-syntax --expose-gc
+  try {
+    /* globals gc, WeakSet */
+    if (typeof gc === 'function') {
+      leakTracking = (() => {
+        // avoid syntax errors when --allow-natives-syntax not present
+        let GetWeakSetValues = new Function('weakSet', 'return %GetWeakSetValues(weakSet, 0)');
+        containers = new WeakSet();
+        return {
+          hasContainers() {
+            gc();
+            return GetWeakSetValues(containers).length > 0;
+          },
+          reset() {
+            let values = GetWeakSetValues(containers);
+            for (let i = 0; i < values.length; i++) {
+              containers.delete(values[i]);
+            }
+          },
+        };
+      })();
+    }
+  } catch (e) {
+    // ignore
+  }
+}
+
 /**
  A container used to instantiate and cache objects.
 
@@ -29,6 +60,9 @@ export default class Container {
 
     if (DEBUG) {
       this.validationCache = dictionary(options.validationCache || null);
+      if (containers !== undefined) {
+        containers.add(this);
+      }
     }
   }
 
@@ -160,6 +194,10 @@ export default class Container {
   }
 }
 
+if (DEBUG) {
+  Container._leakTracking = leakTracking;
+}
+
 /*
  * Wrap a factory manager in a proxy which will not permit properties to be
  * set on the manager.

packages/internal-test-helpers/lib/ember-dev/containers.js

@@ -0,0 +1,34 @@
+import { Container } from 'container';
+
+function ContainersAssert(env) {
+  this.env = env;
+}
+
+const { _leakTracking: containerLeakTracking } = Container;
+
+ContainersAssert.prototype = {
+  reset: function() {},
+  inject: function() {},
+  assert: function() {
+    if (containerLeakTracking === undefined) return;
+    let { config } = QUnit;
+    let { testName, testId, module: { name: moduleName }, finish: originalFinish } = config.current;
+    config.current.finish = function() {
+      originalFinish.call(this);
+      originalFinish = undefined;
+      config.queue.unshift(function() {
+        if (containerLeakTracking.hasContainers()) {
+          containerLeakTracking.reset();
+          // eslint-disable-next-line no-console
+          console.assert(
+            false,
+            `Leaked container after test ${moduleName}: ${testName} testId=${testId}`
+          );
+        }
+      });
+    };
+  },
+  restore: function() {},
+};
+
+export default ContainersAssert;

packages/internal-test-helpers/lib/ember-dev/index.js

@@ -3,6 +3,7 @@ import WarningAssert from './warning';
 import AssertionAssert from './assertion';
 import RunLoopAssert from './run-loop';
 import NamespacesAssert from './namespaces';
+import ContainersAssert from './containers';
 
 import { buildCompositeAssert } from './utils';
 
@@ -12,6 +13,7 @@ var EmberDevTestHelperAssert = buildCompositeAssert([
   AssertionAssert,
   RunLoopAssert,
   NamespacesAssert,
+  ContainersAssert,
 ]);
 
 export default EmberDevTestHelperAssert;