Marks temp files as read-only to avoid saves

CHANGELOG.md

@@ -5,6 +5,9 @@ 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]
+### Changed
+- Marks temporary files (used when showing comparisions with previous revisions) as read-only to help avoid accidental edits/saving
+
 ### Fixed
 - Fixes issues where quick pick menu progress indicators will get stuck in some cases because of a vscode api change in [Microsoft/vscode#46102](https://github.com/Microsoft/vscode/pull/46102)
 

src/git/git.ts

@@ -196,7 +196,10 @@ export class Git {
                             return;
                         }
 
-                        resolve(destination);
+                        const ReadOnly = 0o100444; // 33060 0b1000000100100100
+                        fs.chmod(destination, ReadOnly, err => {
+                            resolve(destination);
+                        });
                     });
                 });
         });