Merge pull request #15013 from atom/as-fix-calling-editor-element-set-model

Swap underlying editor correctly when calling setModel on editor element

spec/text-editor-element-spec.js

@@ -9,6 +9,10 @@ describe('TextEditorElement', () => {
 
   beforeEach(() => {
     jasmineContent = document.body.querySelector('#jasmine-content')
+    // Force scrollbars to be visible regardless of local system configuration
+    const scrollbarStyle = document.createElement('style')
+    scrollbarStyle.textContent = '::-webkit-scrollbar { -webkit-appearance: none }'
+    jasmine.attachToDOM(scrollbarStyle)
   })
 
   function buildTextEditorElement (options = {}) {
@@ -201,6 +205,33 @@ describe('TextEditorElement', () => {
     })
   })
 
+  describe('::setModel', () => {
+    describe('when the element does not have an editor yet', () => {
+      it('uses the supplied one', () => {
+        const element = buildTextEditorElement({attach: false})
+        const editor = new TextEditor()
+        element.setModel(editor)
+        jasmine.attachToDOM(element)
+        expect(editor.element).toBe(element)
+        expect(element.getModel()).toBe(editor)
+      })
+    })
+
+    describe('when the element already has an editor', () => {
+      it('unbinds it and then swaps it with the supplied one', async () => {
+        const element = buildTextEditorElement({attach: true})
+        const previousEditor = element.getModel()
+        expect(previousEditor.element).toBe(element)
+
+        const newEditor = new TextEditor()
+        element.setModel(newEditor)
+        expect(previousEditor.element).not.toBe(element)
+        expect(newEditor.element).toBe(element)
+        expect(element.getModel()).toBe(newEditor)
+      })
+    })
+  })
+
   describe('::onDidAttach and ::onDidDetach', () =>
     it('invokes callbacks when the element is attached and detached', () => {
       const element = buildTextEditorElement({attach: false})

src/text-editor-component.js

@@ -174,6 +174,10 @@ class TextEditorComponent {
   }
 
   update (props) {
+    if (props.model !== this.props.model) {
+      this.props.model.component = null
+      props.model.component = this
+    }
     this.props = props
     this.scheduleUpdate()
   }