Fixes #598 - apply changes not working for 2 refs

Author: eamodio

CHANGELOG.md

@@ -4,6 +4,12 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](http://keepachangelog.com/) and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## [Unreleased]
+
+### Fixed
+
+- Fixes [#598](https://github.com/eamodio/vscode-gitlens/issues/598) — Apply changes when comparing a file from two branches is not working
+
 ## [9.2.1] - 2018-12-16
 
 ### Changed

src/git/gitService.ts

@@ -443,13 +443,18 @@ export class GitService implements Disposable {
     }
 
     @log()
-    async applyChangesToWorkingFile(uri: GitUri, ref?: string) {
-        ref = ref || uri.sha;
-        if (ref === undefined || uri.repoPath === undefined) return;
+    async applyChangesToWorkingFile(uri: GitUri, ref1?: string, ref2?: string) {
+        ref1 = ref1 || uri.sha;
+        if (ref1 === undefined || uri.repoPath === undefined) return;
+
+        if (ref2 === undefined) {
+            ref2 = ref1;
+            ref1 = `${ref1}^`;
+        }
 
         let patch;
         try {
-            patch = await Git.diff(uri.repoPath, uri.fsPath, `${ref}^`, ref);
+            patch = await Git.diff(uri.repoPath, uri.fsPath, ref1, ref2);
             void (await Git.apply(uri.repoPath!, patch));
         }
         catch (ex) {

src/views/viewCommands.ts

@@ -163,6 +163,12 @@ export class ViewCommands implements Disposable {
 
         void (await this.openFile(node));
 
+        if (node instanceof ResultsFileNode) {
+            void (await Container.git.applyChangesToWorkingFile(node.uri, node.ref1, node.ref2));
+
+            return;
+        }
+
         if (node.uri.sha !== undefined && node.uri.sha !== 'HEAD') {
             void (await Container.git.applyChangesToWorkingFile(node.uri));
         }