scratch-desktop

Scratch 3.0 as a standalone desktop application

Documentation

• Windows build matrix — which {target × arch} combinations we ship for Windows and why

Developer Instructions

Releasing a new version

TODO: Update readme once scratch-desktop uses scratch-gui from an npm package

Let's assume that you want to make a new release, version 3.999.0, corresponding to scratch-gui version 0.1.0-prerelease.20yymmdd.

1. Merge scratch-gui:
   1. cd scratch-gui
   2. git pull --all --tags
   3. git checkout scratch-desktop
   4. git merge 0.1.0-prerelease.20yymmdd
   5. Resolve conflicts if necessary
   6. git tag scratch-desktop-v3.999.0
   7. git push
   8. git push --tags
2. Prep scratch-desktop:
   1. cd scratch-desktop
   2. git pull --all --tags
   3. git checkout develop
   4. npm install --save-dev 'scratch-gui@github:scratchfoundation/scratch-gui#scratch-desktop-v3.999.0'
   5. git add package.json package-lock.json
   6. Make sure the app works, the diffs look reasonable, etc.
   7. git commit -m "bump scratch-gui to scratch-desktop-v3.999.0"
   8. npm version 3.999.0
   9. git push
   10. git push --tags
3. Wait for the CI build and collect the release from the build artifacts

A note about scratch-gui

Eventually, the scratch-desktop branch of the Scratch GUI repository will be merged with that repository's main development line. For now, though, the scratch-desktop branch holds a few changes that are necessary for the Scratch app to function correctly but are not yet merged into the main development branch. If you only intend to build or work on the scratch-desktop repository then you can ignore this, but if you intend to work on scratch-gui as well, make sure you use the scratch-desktop branch there.

Previously it was necessary to explicitly build scratch-gui before building scratch-desktop. This is no longer necessary and the related build scripts, such as build-gui, have been removed.

Prepare media library assets

In the scratch-desktop directory, run npm run fetch. Re-run this any time you update scratch-gui or make any other changes which might affect the media libraries.

Run in development mode

npm start

Make a packaged build

npm run dist

Note that on macOS this will require installing various certificates.

Code signing (Windows)

For an unsigned local build, use npm run distDev (it needs no signing configuration). npm run dist is the signed release build; on Windows it requires Azure Artifact Signing credentials, so in practice it runs only in CI.

Signed Windows builds are produced only in CI. The release-candidate workflow signs the NSIS and MSI installers with Azure Artifact Signing, and leaves the Store AppX unsigned because the Microsoft Store re-signs it during certification. (The earlier WIN_CSC_LINK / WIN_CSC_KEY_PASSWORD certificate flow has been removed.) See the Windows build matrix for the full set of shipping artifacts and how each is produced.

Workaround for code signing issue in macOS

Sometimes the macOS build process will result in a build which crashes on startup. If this happens, check in Console for an entry similar to this:

failed to parse entitlements for Scratch[12345]: OSUnserializeXML: syntax error near line 1

This appears to be an issue with codesign itself. Rebooting your computer and trying to build again might help. Yes, really.

See this issue for more detail: electron/osx-sign#218

Make a semi-packaged build

This will simulate a packaged build without actually packaging it: instead the files will be copied to a subdirectory of dist.

npm run dist:dir

Debugging

You can debug the renderer process by opening the Chromium development console. This should be the same keyboard shortcut as Chrome on your platform. This won't work on a packaged build.

You can debug the main process the same way as any Node.js process. I like to use Visual Studio Code with a configuration like this:

    "launch": {
        "version": "0.2.0",
        "configurations": [
            {
                "name": "Desktop",
                "type": "node",
                "request": "launch",
                "cwd": "${workspaceFolder:scratch-desktop}",
                "runtimeExecutable": "npm",
                "autoAttachChildProcesses": true,
                "runtimeArgs": ["start", "--"],
                "protocol": "inspector",
                "skipFiles": [
                    // it seems like skipFiles only reliably works with 1 entry :(
                    //"<node_internals>/**",
                    "${workspaceFolder:scratch-desktop}/node_modules/electron/dist/resources/*.asar/**"
                ],
                "sourceMaps": true,
                "timeout": 30000,
                "outputCapture": "std"
            }
        ]
    },

Resetting the Telemetry System

This application includes a telemetry system which is only active if the user opts in. When testing this system, it's sometimes helpful to reset it by deleting the telemetry.json file.

The location of this file depends on your operating system and whether or not you're running a packaged build. Running from npm start or equivalent is a non-packaged build.

In addition, macOS may store the file in one of two places depending on the OS version and a few other variables. If in doubt, I recommend removing both.

• Windows, packaged build: %APPDATA%\Scratch\telemetry.json
• Windows, non-packaged: %APPDATA%\Electron\telemetry.json
• macOS, packaged build: ~/Library/Application Support/Scratch/telemetry.json or ~/Library/Containers/edu.mit.scratch.scratch-desktop/Data/Library/Application Support/Scratch/telemetry.json
• macOS, non-packaged build: ~/Library/Application Support/Electron/telemetry.json or ~/Library/Containers/edu.mit.scratch.scratch-desktop/Data/Library/Application Support/Electron/telemetry.json

Deleting this file will:

• Remove any pending telemetry packets
• Reset the opt in/out state: the app should display the opt in/out modal on next launch
• Remove the random client UUID: the app will generate a new one on next launch