fix: prevent double source buffer ready on IE11 (#1015)

src/source-updater.js

@@ -337,13 +337,12 @@ export default class SourceUpdater extends videojs.EventTarget {
  };
  this.createdSourceBuffers_ = false;
  this.initializedEme_ = false;
+ this.triggeredReady_ = false;
  }
 
  initializedEme() {
  this.initializedEme_ = true;
- if (this.ready()) {
- this.trigger('ready');
- }
+ this.triggerReady();
  }
 
  hasCreatedSourceBuffers() {
@@ -371,7 +370,18 @@ export default class SourceUpdater extends videojs.EventTarget {
  this.addOrChangeSourceBuffers(codecs);
  this.createdSourceBuffers_ = true;
  this.trigger('createdsourcebuffers');
- if (this.ready()) {
+ this.triggerReady();
+ }
+
+ triggerReady() {
+ // only allow ready to be triggered once, this prevents the case
+ // where:
+ // 1. we trigger createdsourcebuffers
+ // 2. ie 11 synchronously initializates eme
+ // 3. the synchronous initialization causes us to trigger ready
+ // 4. We go back to the ready check in createSourceBuffers and ready is triggered again.
+ if (this.ready() && !this.triggeredReady_) {
+ this.triggeredReady_ = true;
  this.trigger('ready');
  }
  }

test/videojs-http-streaming.test.js

@@ -4640,7 +4640,14 @@ QUnit.test('integration: updates source updater after eme init', function(assert
  sourceUpdater.on(
  'createdsourcebuffers',
  () => {
- assert.notOk(sourceUpdater.hasInitializedAnyEme(), 'has not initialized eme yet');
+ let expected = false;
+
+ // IE initializes eme syncronously directly after source buffer
+ // creation
+ if (videojs.browser.IE_VERSION) {
+ expected = true;
+ }
+ assert.equal(sourceUpdater.hasInitializedAnyEme(), expected, 'correct eme state');
  }
  );
 
@@ -4661,7 +4668,7 @@ QUnit.test('integration: updates source updater after eme init', function(assert
  this.standardXHRResponse(this.requests.shift(), audioSegment());
 });
 
-QUnit.test('player error when key session creation rejects promise', function(assert) {
+QUnit[testOrSkip]('player error when key session creation rejects promise', function(assert) {
  const done = assert.async();
 
  this.player.error = (errorObject) => {