From dfc8398badba6a77bf93dc6ced7a1425d1fb5d16 Mon Sep 17 00:00:00 2001
From: Kevin Schaaf <kschaaf@google.com>
Date: Tue, 24 Jul 2018 11:47:29 -0700
Subject: [PATCH] Revert to legacy template getter, update tests.

---
 lib/legacy/class.html                 | 18 ++++++++++
 lib/mixins/element-mixin.html         | 50 +++++++++++++--------------
 test/unit/behaviors.html              | 32 ++++++++++++-----
 test/unit/strict-template-policy.html | 35 ++++++++++++-------
 4 files changed, 90 insertions(+), 45 deletions(-)

diff --git a/lib/legacy/class.html b/lib/legacy/class.html
index 026fa98eef..0c8acab5b2 100644
--- a/lib/legacy/class.html
+++ b/lib/legacy/class.html
@@ -152,6 +152,24 @@
           return info.observers;
         }
 
+        /**
+         * @return {HTMLTemplateElement} template for this class
+         */
+        static get template() {
+          if (!this.hasOwnProperty(JSCompiler_renameProperty('_template', this))) {
+            this._template =                  
+              // Accept template: _null to short-circuit dom-module lookup
+              info._template !== undefined ? info._template : 
+              // Look in dom-module associated with this element's is
+              this._getTemplateFromDomModule() ||
+              // Look up in the chain
+              Base.template ||
+              // Use any template set on the prototype via registered callback
+              this.prototype._template;
+          }
+          return this._template;
+        }
+
         /**
          * @return {void}
          */
diff --git a/lib/mixins/element-mixin.html b/lib/mixins/element-mixin.html
index b2082f292a..032ad27708 100644
--- a/lib/mixins/element-mixin.html
+++ b/lib/mixins/element-mixin.html
@@ -275,27 +275,6 @@
       }
     }
 
-    /**
-     * Look up template from dom-module for element
-     * 
-     * @param {!string} is Element name to look up
-     * @return {!HTMLTemplateElement} Template found in dom module, or
-     *   undefined if not found
-     * @private
-     */
-     function getTemplateFromDomModule(is) {
-      let template = null;
-      if (is && Polymer.DomModule) {
-        template = Polymer.DomModule.import(is, 'template');
-        // Under strictTemplatePolicy, require any element with an `is`
-        // specified to have a dom-module
-        if (Polymer.strictTemplatePolicy && !template) {
-          throw new Error(`strictTemplatePolicy: expecting dom-module or null template for ${is}`);
-        }
-      }
-      return template;
-    }
-
     /**
      * @polymer
      * @mixinClass
@@ -368,6 +347,30 @@
         }
       }
 
+      /**
+       * Look up template from dom-module for element
+       * 
+       * @param {!string} is Element name to look up
+       * @return {!HTMLTemplateElement} Template found in dom module, or
+       *   undefined if not found
+       * @protected
+       */
+      static _getTemplateFromDomModule() {
+        let template = null;
+        const is = /** @type {PolymerElementConstructor}*/ (this).is;
+        // Under strictTemplatePolicy in 3.x+, dom-module lookup is only allowed
+        // when opted-in via allowTemplateFromDomModule
+        if (is && Polymer.DomModule) {
+          template = Polymer.DomModule.import(is, 'template');
+          // Under strictTemplatePolicy, require any element with an `is`
+          // specified to have a dom-module
+          if (Polymer.strictTemplatePolicy && !template) {
+            throw new Error(`strictTemplatePolicy: expecting dom-module or null template for ${is}`);
+          }
+        }
+        return template;
+      }
+
       /**
        * Returns the template that will be stamped into this element's shadow root.
        *
@@ -408,11 +411,8 @@
       static get template() {
         if (!this.hasOwnProperty(JSCompiler_renameProperty('_template', this))) {
           this._template =
-            // Take any template set on the prototype, including null (for legacy
-            // support, setting in registered callback, etc.)
-            this.prototype._template !== undefined ? this.prototype._template :
             // Look in dom-module associated with this element's is
-            getTemplateFromDomModule(/** @type {PolymerElementConstructor}*/ (this).is) ||
+            this._getTemplateFromDomModule() ||
             // Next look for superclass template (call the super impl this
             // way so that `this` points to the superclass)
             Object.getPrototypeOf(/** @type {PolymerElementConstructor}*/ (this).prototype).constructor.template;
diff --git a/test/unit/behaviors.html b/test/unit/behaviors.html
index ffa011f562..3a9c915f50 100644
--- a/test/unit/behaviors.html
+++ b/test/unit/behaviors.html
@@ -22,7 +22,7 @@
     </template>
   </dom-module>
 
-  <dom-module id="template-from-behavior">
+  <dom-module id="template-from-base">
     <template>
       <div id="from-base">should not be used</div>
     </template>
@@ -298,9 +298,9 @@
       _template: Polymer.html`<div id="from-behavior2"></div>`
     };
 
-    window.templateBehaviorFromRegister = {
+    window.templateBehaviorFromRegistered = {
       registered: function() {
-        this._template = Polymer.html`<div id="behavior-from-register"></div>`;
+        this._template = Polymer.html`<div id="behavior-from-registered"></div>`;
       }
     };
 
@@ -311,6 +311,13 @@
       }
     });
 
+    Polymer({
+      is: 'template-from-base',
+      behaviors: [
+        window.templateBehavior1
+      ]
+    });
+
     Polymer({
       is: 'template-from-behavior',
       behaviors: [
@@ -329,8 +336,7 @@
     Polymer({
       is: 'template-from-behavior-registered',
       behaviors: [
-        window.templateBehavior1,
-        window.templateBehaviorFromRegister
+        window.templateBehaviorFromRegistered
       ]
     });
 
@@ -367,6 +373,12 @@
     </template>
   </test-fixture>
 
+  <test-fixture id="from-base">
+    <template>
+      <template-from-base></template-from-base>
+    </template>
+  </test-fixture>
+
   <test-fixture id="from-behavior">
     <template>
       <template-from-behavior></template-from-behavior>
@@ -588,9 +600,14 @@
     assert.ok(el.shadowRoot.querySelector('#from-registered'));
   });
 
+  test('template from base', function() {
+    var el = fixture('from-base');
+    assert.ok(el.shadowRoot.querySelector('#from-base'));
+    assert.notOk(el.shadowRoot.querySelector('#from-behavior1'));
+  });
+
   test('template from behavior', function() {
     var el = fixture('from-behavior');
-    assert.notOk(el.shadowRoot.querySelector('#from-base'));
     assert.ok(el.shadowRoot.querySelector('#from-behavior1'));
   });
 
@@ -602,8 +619,7 @@
 
   test('template from behavior registered callback', function() {
     var el = fixture('from-behavior-registered');
-    assert.notOk(el.shadowRoot.querySelector('#from-behavior1'));
-    assert.ok(el.shadowRoot.querySelector('#behavior-from-register'));
+    assert.ok(el.shadowRoot.querySelector('#behavior-from-registered'));
   });
 
 });
diff --git a/test/unit/strict-template-policy.html b/test/unit/strict-template-policy.html
index 706273115c..982b3b97ff 100644
--- a/test/unit/strict-template-policy.html
+++ b/test/unit/strict-template-policy.html
@@ -128,11 +128,15 @@
       const onerror = window.onerror;
       const topOnerror = window.top.topOnerror;
 
-      teardown(function() {
-        // Restore mocha's onerror
+      function restoreOnError() {
         window.onerror = onerror;
         window.top.onerror = topOnerror;
         window.uncaughtErrorFilter = window.top.uncaughtErrorFilter = null;
+      }
+
+      teardown(function() {
+        // Restore mocha's onerror
+        restoreOnError();
         document.getElementById('target').textContent = '';
       });
 
@@ -166,6 +170,7 @@
             throw uncaughtError;
           }
         }, re);
+        restoreOnError();
       }
 
       test('dom-bind', function() {
@@ -213,9 +218,12 @@
             '  </template>`' +
             '</dom-module>';
         }, /trusted-element re-registered/);
-        const el = document.createElement('trusted-element');
-        document.getElementById('target').appendChild(el);
-        assert.notOk(el.shadowRoot);
+        let el;
+        assertThrows(function() {
+          el = document.createElement('trusted-element');
+          document.getElementById('target').appendChild(el);
+        }, /expecting dom-module or null template/);
+        assert.notOk(el && el.shadowRoot);
         assert.notOk(document.getElementById('injected'));
       });
       
@@ -230,7 +238,7 @@
         }, /trusted-element re-registered/);
         const el = document.createElement('trusted-element');
         document.getElementById('target').appendChild(el);
-        assert.notOk(el.shadowRoot);
+        assert.notOk(el && el.shadowRoot);
         assert.notOk(document.getElementById('injected'));
       });
       
@@ -261,9 +269,12 @@
             '  </template>`' +
             '</dom-module>';
         }, /trusted-element-legacy re-registered/);
-        const el = document.createElement('trusted-element-legacy');
-        document.getElementById('target').appendChild(el);
-        assert.notOk(el.shadowRoot);
+        let el;
+        assertThrows(function() {
+          el = document.createElement('trusted-element-legacy');
+          document.getElementById('target').appendChild(el);
+        }, /expecting dom-module or null template/);
+        assert.notOk(el && el.shadowRoot);
         assert.notOk(document.getElementById('injected'));
       });
       
@@ -276,9 +287,9 @@
             '  </template>`' +
             '</dom-module>';
         }, /trusted-element-legacy re-registered/);
-        const el = document.createElement('trusted-element-legacy');
+        const el = document.createElement('trusted-element');
         document.getElementById('target').appendChild(el);
-        assert.notOk(el.shadowRoot);
+        assert.notOk(el && el.shadowRoot);
         assert.notOk(document.getElementById('injected'));
       });
       
@@ -292,7 +303,7 @@
         Polymer({
           is: 'has-no-template-legacy',
           _template: null
-        });
+        }, /expecting dom-module or null template/);
         let el = document.createElement('has-no-template-legacy');
         document.getElementById('target').appendChild(el);
         assert.notOk(el.shadowRoot);