Refresh open file on pull (#1090)

* Refresh open file on pull

Currently doing a pull does not update the contents of open files
like switches branches does.

Fixes #1086

* Fix failing test by adding null check and awaits

Author: ajbozarth

src/model.ts

@@ -824,7 +824,8 @@ export class GitExtension implements IGitExtension {
    */
   async pull(auth?: Git.IAuth): Promise<Git.IResultWithMessage> {
     const path = await this._getPathRepository();
-    const data = this._taskHandler.execute<Git.IResultWithMessage>(
+    const previousHead = this._currentBranch?.top_commit;
+    const data = await this._taskHandler.execute<Git.IResultWithMessage>(
       'git:pull',
       async () => {
         return await requestAPI<Git.IResultWithMessage>(
@@ -840,7 +841,9 @@ export class GitExtension implements IGitExtension {
         );
       }
     );
-    this.refreshBranch(); // Will emit headChanged if required
+    const changes = await this._changedFiles(previousHead, 'HEAD');
+    changes?.files?.forEach(file => this._revertFile(file));
+    await this.refreshBranch(); // Will emit headChanged if required
     return data;
   }