From 2cab461a87c70156838d3471c6cfa05990c3b09e Mon Sep 17 00:00:00 2001
From: Daniel Freedman <dfreedm@google.com>
Date: Wed, 27 Jul 2016 15:09:42 -0700
Subject: [PATCH] [apply shim] Track dependencies for mixins before creation

Fixes #3802 (again)
---
 src/lib/apply-shim.html                  |  8 ++++-
 test/unit/styling-cross-scope-apply.html | 46 ++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/src/lib/apply-shim.html b/src/lib/apply-shim.html
index 941c46c680..42b1504fa0 100644
--- a/src/lib/apply-shim.html
+++ b/src/lib/apply-shim.html
@@ -99,7 +99,13 @@
 
   function mapGet(name) {
     name = name.trim();
-    return mixinMap[name];
+    var entry = mixinMap[name];
+    // if the mixin is not defined, make an entry so we can set up dependencies correctly
+    if (!entry) {
+      mapSet(name, {});
+      entry = mixinMap[name];
+    }
+    return entry;
   }
 
   // "parse" a mixin definition into a map of properties and values
diff --git a/test/unit/styling-cross-scope-apply.html b/test/unit/styling-cross-scope-apply.html
index 379c0db7b8..bd6c299bb2 100644
--- a/test/unit/styling-cross-scope-apply.html
+++ b/test/unit/styling-cross-scope-apply.html
@@ -533,6 +533,43 @@
 }
 </style>
 
+<dom-module id="x-apply-depend-before-create">
+  <template>
+    <style>
+    :host {
+      @apply --before-create;
+    }
+    </style>
+  </template>
+  <script>
+  HTMLImports.whenReady(function() {
+    Polymer({
+      is: 'x-apply-depend-before-create'
+    })
+  })
+  </script>
+</dom-module>
+
+<dom-module id="x-create-after-apply">
+  <template>
+    <style>
+    :host {
+      --before-create: {
+        border: 2px solid green;
+      }
+    }
+    </style>
+    <x-apply-depend-before-create id="child"></x-apply-depend-before-create>
+  </template>
+  <script>
+  HTMLImports.whenReady(function() {
+    Polymer({
+      is: 'x-create-after-apply'
+    })
+  })
+  </script>
+</dom-module>
+
 <script>
 suite('scoped-styling-apply', function() {
   function assertComputed(element, value, property) {
@@ -736,6 +773,15 @@
       assert.equal(parent2Text, parent3Text, 'x-produce-mixin-3 should not have invalidated x-consume-mixin');
     }
   });
+
+  test('mixins can be depended on before creation', function() {
+    var e = document.createElement('x-apply-depend-before-create');
+    document.body.appendChild(e);
+    var e2 = document.createElement('x-create-after-apply');
+    document.body.appendChild(e2);
+    CustomElements.takeRecords();
+    assertComputed(e2.$.child, '2px');
+  });
 });
 
 </script>