Flashback Diff
See any file as it was when your branch was born.
Right-click a file → diff it against the point where your branch started.
When you work on a feature branch, the question you usually care about is
"what have I changed in this file since I branched off?". Not the last commit,
and not the current tip of main, which may have moved on since then.
Flashback Diff answers that with one click. It finds the commit your branch grew
from (the merge-base with its origin branch) and opens VS Code's native diff
editor next to your current file.
Features
- One click from anywhere. Use the Explorer context menu, the editor context menu,
the tab context menu, or the button in the editor title bar.
- Smart origin detection. Works out which branch you created your branch from, including
git checkout -b, git switch -c and git branch <name> <start>.
- Honest diffs. Compares against the merge-base, so changes that landed on
main
after you branched don't show up as noise.
- Edit while you compare. The right side is your real file, with full IntelliSense,
saving and formatting.
- New files are handled. Files added on your branch are compared against an empty file.
- Zero setup. No configuration needed. You can still override the origin when you want to.
Usage
- Right-click a file in the Explorer, in the editor, or on its tab.
- Select Compare with Branch Origin.
The diff opens with the origin on the left and your working copy on the right:
login.ts (develop @ 3f2a1c9) ↔ feature/login
Commands
| Command |
Description |
Flashback Diff: Compare with Branch Origin |
Diff the current file against its branch origin. |
Flashback Diff: Choose Branch Origin… |
Pick the origin branch by hand. The choice is remembered per repository and branch. |
Flashback Diff: Reset Branch Origin Detection |
Forget manual choices and go back to automatic detection. |
How the origin is detected
Flashback Diff tries each of these in order and stops at the first one that works:
- Your setting.
flashbackDiff.baseBranch, if set.
- Your choice. A branch you picked with Choose Branch Origin….
- Git reflog. The record of where the branch was created
(
branch: Created from develop, or checkout: moving from develop to feature/login).
- Closest ancestor. The local or remote branch whose merge-base is nearest to
HEAD.
Ties are broken by flashbackDiff.preferredBranches, then by local over remote.
- Ask. If nothing else works, you get a quick pick.
The reflog only exists on the machine where the branch was created. On a fresh clone,
detection falls back to step 4. If it guesses wrong, choose the origin once and it is remembered.
Detection details are written to the Flashback Diff output channel
(View → Output).
Settings
| Setting |
Default |
Description |
flashbackDiff.baseBranch |
"" |
Always compare against this branch (e.g. main, origin/develop). Empty means automatic. |
flashbackDiff.preferredBranches |
["main", "master", "develop", "dev"] |
Branches preferred when several candidates are equally close. |
flashbackDiff.showTitleButton |
true |
Show the compare button in the editor title bar. |
Requirements
- VS Code 1.75 or newer
- Git available on your
PATH
- A trusted workspace (the extension runs git commands)
Privacy and security
- Fully local. No network requests, no telemetry, no runtime dependencies.
- Read-only. Runs only read-only git commands (
rev-parse, reflog, for-each-ref, merge-base, rev-list, show) and never changes your repository.
- Trusted workspaces only. The extension is disabled in Restricted Mode, the same way VS Code's built-in Git is.
- No shell. Git is called directly with argument lists, using the git binary VS Code's Git extension resolved. Branch names and settings are validated before use.
Found a vulnerability? Please report it privately through
GitHub Security Advisories instead of opening a public issue.
Contributing
Issues and pull requests are welcome.
git clone https://github.com/vhme/flashback-diff.git
cd flashback-diff
npm install
npm test # compile + run the test suite
npm run lint
Press F5 in VS Code to launch an Extension Development Host with the extension loaded.
License
MIT © vhme
