Update amending commit message when expanded commit editor is closed

lib/controllers/commit-view-controller.js

@@ -56,7 +56,11 @@ export default class CommitViewController {
             this.getCommitMessageEditors().length === 0) {
           // we closed the last editor pointing to the commit message file
           try {
-            this.regularCommitMessage = await readFile(this.getCommitMessagePath());
+            if (this.props.isAmending && this.props.lastCommit.isPresent()) {
+              this.amendingCommitMessage = await readFile(this.getCommitMessagePath());
+            } else {
+              this.regularCommitMessage = await readFile(this.getCommitMessagePath());
+            }
           } catch (e) {
             if (e.code !== 'ENOENT') {
               throw e;

test/controllers/commit-view-controller.test.js

@@ -176,6 +176,32 @@ describe('CommitViewController', function() {
         await assert.async.equal(controller.refs.commitView.editor.getText(), 'message in editor');
       });
 
+      it('transfers the commit message contents when in amending state', async function() {
+        const originalMessage = 'message in box before amending';
+        controller.refs.commitView.editor.setText(originalMessage);
+
+        await controller.update({isAmending: true, lastCommit});
+        assert.equal(controller.refs.commitView.editor.getText(), lastCommit.getMessage());
+
+        commandRegistry.dispatch(atomEnvironment.views.getView(workspace), 'github:toggle-expanded-commit-message-editor');
+        await assert.async.equal(workspace.getActiveTextEditor().getPath(), controller.getCommitMessagePath());
+        const editor = workspace.getActiveTextEditor();
+        assert.equal(editor.getText(), lastCommit.getMessage());
+
+        const amendedMessage = lastCommit.getMessage() + 'plus some changes';
+        editor.setText(amendedMessage);
+        await editor.save();
+
+        editor.destroy();
+        await assert.async.equal(controller.refs.commitView.editor.getText(), amendedMessage);
+
+        await controller.update({isAmending: false});
+        await assert.async.equal(controller.refs.commitView.editor.getText(), originalMessage);
+
+        await controller.update({isAmending: true, lastCommit});
+        assert.equal(controller.refs.commitView.editor.getText(), amendedMessage);
+      });
+
       it('activates editor if already opened but in background', async function() {
         commandRegistry.dispatch(atomEnvironment.views.getView(workspace), 'github:toggle-expanded-commit-message-editor');
         await assert.async.equal(workspace.getActiveTextEditor().getPath(), controller.getCommitMessagePath());