This extension helps testing and developing various features (such as the merge and diff editor) in VS Code by providing some diagnostic/development features.
The target audience of this extension are developers working on VS Code itself or users that file bugs for VS Code.
Commands
Diagnose Diff Editor: Report Bug
Use this command to quickly report a bug for the diff editor.
It will pre-fill the GitHub form to create an issue in the vscode repository.
The pre-filled form includes a link to the monaco editor playground.
If you only want to share a fragment of the diff, select text on either side before invoking this command.
Diagnose Diff Editor: Open In Monaco Editor Playground
Use this command to open the current diff in the monaco editor playground.
Used for the report bug functionality.
In merge-conflict
folders: Reproduce Conflict In Playground
This commands expects the folder to contain the files base.ext
, input1.ext
, and input2.ext
(ext
being some file extension, e.g. ts
).
Invoking the command creates a git conflict in a given folder, where input2 is merged into input1 and base being the common base.
In merge-conflict
folders: Open Folder In Merge Editor
This command expects the folder to contain the files base.ext
, input1.ext
, and input2.ext
(ext
being some file extension, e.g. ts
).
Invoking the command opens the merge editor for the given files.
Custom Editors
Diff JSON Viewer
This viewer is used to display the diffs produced by the VS Code diff snapshot tests.

Debugger Scripts
This extension allows to run custom scripts when debugging in VS Code.
The VS Code repository makes use of this to enable hot reloading.
Configuration
Custom scripts can be specified with the vscode-diagnostic-tools.debuggerScripts
property in the corresponding launch config of the debug session.
The debugger scripts property is expected to be an array of absolute file paths. Use ${workspaceFolder}
to refer to the workspace folder of the launch config.
For example:
{
"version": "0.2.0",
"configurations": [
{
"name": "Run Extension",
"type": "extensionHost",
"request": "launch",
"args": ["--extensionDevelopmentPath=${workspaceFolder}",],
"outFiles": ["${workspaceFolder}/out/**/*.js"],
"vscode-diagnostic-tools.debuggerScripts": [
"${workspaceFolder}/scripts/my-debugger-script.js"
]
}
]
}
Scripts
A debugger script is a NodeJS module which is expected to export a function called run
of type RunFunction
.
This function is called for every new debug session. The returned dispose function is called when the debug session ends (or when the debugger script is reloaded).
Such a script could look like this:
// @ts-check
/// <reference path='debugger-scripts-api.d.ts' />
console.log('script loaded');
/** @type {RunFunction} */
module.exports.run = async function (debugSession) {
console.log('script started');
// This code runs in the debugger
debugSession.evalJs(function (data) {
// This code runs in the debuggee (assuming it can evaluate JS expressions)
console.log(data);
}, 'some JSON serializable data');
return {
dispose() {
console.log('script stopped');
}
};
};
Debugger scripts are automatically reloaded when changed.
Before the new script is loaded and executed, the dispose
function of the previous script is called.
The dispose
function is also called when the debug session stops.
When multiple debug sessions load the same script, the script is only loaded once, however, the run
function is called for every debug session.
Contributing
This project welcomes contributions and suggestions. Most contributions require you to agree to a
Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us
the rights to use your contribution. For details, visit https://cla.opensource.microsoft.com.
When you submit a pull request, a CLA bot will automatically determine whether you need to provide
a CLA and decorate the PR appropriately (e.g., status check, comment). Simply follow the instructions
provided by the bot. You will only need to do this once across all repos using our CLA.
This project has adopted the Microsoft Open Source Code of Conduct.
For more information see the Code of Conduct FAQ or
contact opencode@microsoft.com with any additional questions or comments.
Trademarks
This project may contain trademarks or logos for projects, products, or services. Authorized use of Microsoft
trademarks or logos is subject to and must follow
Microsoft's Trademark & Brand Guidelines.
Use of Microsoft trademarks or logos in modified versions of this project must not cause confusion or imply Microsoft sponsorship.
Any use of third-party trademarks or logos are subject to those third-party's policies.