From ba697ef5907f83719be2eb4782e3a34d4b686acd Mon Sep 17 00:00:00 2001
From: Niklas Mischkulnig <mischnic@users.noreply.github.com>
Date: Sun, 3 Mar 2019 23:14:05 +0100
Subject: [PATCH] Don't execute twice on HMR full reload

---
 packages/core/integration-tests/test/hmr.js   | 17 ++++++++--
 .../src/builtins/hmr-runtime.js               | 32 +++++++++++--------
 2 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/packages/core/integration-tests/test/hmr.js b/packages/core/integration-tests/test/hmr.js
index eb3b2dfff50..bf4aa9ffedd 100644
--- a/packages/core/integration-tests/test/hmr.js
+++ b/packages/core/integration-tests/test/hmr.js
@@ -404,10 +404,22 @@ describe('hmr', function() {
     });
     let bundle = await b.bundle();
 
-    let ctx = await run(bundle, {output() {}}, {require: false});
-
+    let outputs = [];
+    let ctx = await run(
+      bundle,
+      {
+        output(o) {
+          outputs.push(o);
+        }
+      },
+      {require: false}
+    );
     let spy = sinon.spy(ctx.location, 'reload');
 
+    await sleep(50);
+    assert.deepEqual(outputs, [3]);
+    assert(spy.notCalled);
+
     await sleep(100);
     fs.writeFile(
       path.join(__dirname, '/input/local.js'),
@@ -415,6 +427,7 @@ describe('hmr', function() {
     );
 
     await nextEvent(b, 'bundled');
+    assert.deepEqual(outputs, [3]);
     assert(spy.calledOnce);
   });
 
diff --git a/packages/core/parcel-bundler/src/builtins/hmr-runtime.js b/packages/core/parcel-bundler/src/builtins/hmr-runtime.js
index da4199c7c77..49c12e8ba84 100644
--- a/packages/core/parcel-bundler/src/builtins/hmr-runtime.js
+++ b/packages/core/parcel-bundler/src/builtins/hmr-runtime.js
@@ -33,23 +33,27 @@ if ((!parent || !parent.isParcelRequire) && typeof WebSocket !== 'undefined') {
     var data = JSON.parse(event.data);
 
     if (data.type === 'update') {
-      console.clear();
-
-      data.assets.forEach(function (asset) {
-        hmrApply(global.parcelRequire, asset);
-      });
-
       var handled = false;
-      data.assets.forEach(function (asset) {
-        if (!asset.isNew) {
-          var didAccept = hmrAccept(global.parcelRequire, asset.id);
-          if (didAccept) {
-            handled = true;
-          }
-        }
+      data.assets.forEach(function(asset){
+        handled = handled ||
+          Boolean(global.parcelRequire.cache[asset.id].hot._acceptCallbacks.length) ||
+          Boolean(global.parcelRequire.cache[asset.id].hot._disposeCallbacks.length);
       });
 
-      if(!handled) {
+      if(handled){
+        console.clear();
+
+        data.assets.forEach(function (asset) {
+          hmrApply(global.parcelRequire, asset);
+        });
+
+        var handled = false;
+        data.assets.forEach(function (asset) {
+          if (!asset.isNew) {
+            hmrAccept(global.parcelRequire, asset.id);
+          }
+        });
+      } else {
         window.location.reload();
       }
     }