Fresh Windows checkout: lint, the root build and `scratch-gui` unit tests fail without any code changes

Start with the root .gitattributes and packages/scratch-gui/package.json; the issue identifies the three failing commands and their causes. Check the existing *.js line-ending rule, the neighboring build scripts, and the quoted Jest patterns in scratch-storage. Done when a fresh Windows checkout passes lint and the root build, and test:unit runs only the unit suites.

Hello! Windows-native developer here. I found a few issues that come up when using Windows and they are small and easy changes that would allow better cross-os developer collaboration. None of these issues affect scratch users or CI, and each is a one-line fix. I searched issues and PRs and found no prior work or reports on these. Details below:

Expected Behavior

On a fresh clone of develop with npm ci done, a Windows contributor can run the same commands
as on Linux or macOS with the same results:

• npm run lint / npm run test:lint passes in every package.
• npm run build from the repo root builds all eight packages.
• npm run test:unit in packages/scratch-gui runs only the unit suites.

Actual Behavior

Three independent things go wrong, none of which involve a code change. CI is unaffected because
it runs on Linux. Each has a one-line cause and a workaround.

1. Lint fails in seven of eight packages because .mjs files check out with CRLF

With Git for Windows' default core.autocrlf=true, every eslint.config.mjs, typedoc.config.mjs,
prettier.config.mjs and scripts/prepare.mjs is checked out with CRLF. ESLint then reports one
error per line in each of them:

  1:59   error  Expected linebreaks to be 'LF' but found 'CRLF'  @stylistic/linebreak-style
  2:45   error  Expected linebreaks to be 'LF' but found 'CRLF'  @stylistic/linebreak-style
  ...

and in task-herder Prettier fails the same way:

[warn] eslint.config.mjs
[warn] prettier.config.mjs
[warn] Code style issues found in 2 files. Run Prettier with --write to fix.

Error counts on an untouched checkout: scratch-gui 241, scratch-paint 72, scratch-vm 56,
scratch-render 53, scratch-svg-renderer 52, scratch-storage 47. Only scratch-media-lib-scripts
passes, because it has no .mjs files.

Cause: .gitattributes sets text eol=lf for *.js, *.jsx, *.ts, *.tsx, *.json and many
other types, but has no entry for *.mjs. git check-attr eol -- packages/scratch-vm/eslint.config.mjs
reports eol: unspecified, so the 14 tracked .mjs files follow core.autocrlf instead.

Workaround: git config core.autocrlf false in the clone and re-checkout.

2. npm run build exits 1 at scratch-gui

The seven other packages build, then:

> @scratch/[email protected] build:dev
> BUILD_TYPE=dev webpack

'BUILD_TYPE' is not recognized as an internal or external command,
operable program or batch file.

Cause: packages/scratch-gui/package.json has "build:dev": "BUILD_TYPE=dev webpack". That is
POSIX shell syntax, and npm runs scripts through cmd.exe on Windows regardless of the calling
shell. The neighbouring build:dist and build:dist-standalone scripts already use cross-env
for the same variable, and cross-env is already in scratch-gui's devDependencies.

Workaround: npm run build --workspace=packages/scratch-gui --script-shell="C:\Program Files\Git\bin\bash.exe".

3. scratch-gui npm run test:unit runs every suite

Jest rejects the path pattern and falls back to running everything:

  Invalid testPattern test[\\\]unit supplied. Running all tests instead.

The unit, integration, Playwright and smoke suites then run together. Without a gui build and
browsers that shows as 21 failed suites (127 failed, 328 passed of 463 tests) instead of the 50
unit suites passing. test:integration and test:smoke use the same pattern shape.

Cause: the patterns in packages/scratch-gui/package.json are passed unquoted:

"test:unit": "cross-env JEST_JUNIT_OUTPUT_NAME=unit-tests-results.xml jest test[\\\\/]unit",
"test:integration": "cross-env JEST_JUNIT_OUTPUT_NAME=integration-tests-results.xml jest --maxWorkers=4 test[\\\\/]integration",
"test:smoke": "jest --runInBand test[\\\\/]smoke",

Through cmd.exe the pattern reaches Jest as an invalid regex. scratch-storage passes the same
kind of pattern in double quotes (jest "test[\\\\/]unit") and works on Windows. The scratch-gui
README's advice to use cmd.exe instead of Git Bash makes no difference, because npm runs the
script through cmd.exe either way; the result is identical from PowerShell and Git Bash.

Workaround: npx jest test/unit runs exactly the unit suites (50 suites, 328 passed, 1 skipped,
about 10 seconds).

Steps to Reproduce

1. On Windows with Git for Windows defaults (core.autocrlf=true), clone scratch-editor, check
   out develop, run npm ci from the repo root.
2. cd packages/scratch-vm and run npm run lint: see the @stylistic/linebreak-style errors.
   Any package other than scratch-media-lib-scripts shows the same.
3. From the repo root run npm run build: see 'BUILD_TYPE' is not recognized and exit code 1
   after the other seven packages build.
4. cd packages/scratch-gui and run npm run test:unit: see Invalid testPattern ... Running all tests instead. followed by integration, Playwright and smoke suites running. Compare with
   npx jest test/unit, which runs only the unit suites and passes.

System Details

• Windows 10 Pro 22H2 (build 19045); identical results from PowerShell 5.1 and Git Bash
• Git for Windows with core.autocrlf=true; npm script-shell unset (scripts run in cmd.exe)
• Node v24.21.0, npm 12.0.2, Jest 29.7.0
• scratch-editor develop at 7b5559d29 (v15.3.0), fresh npm ci

Notes

Each cause has a small, self-contained fix, and I would be glad to open them as two separate PRs
referencing this issue so each is easy to review:

1. Add *.mjs text eol=lf to .gitattributes. The committed blobs are already LF, so only
   checkout behaviour changes. Existing Windows clones need a re-checkout
   (git rm --cached -r . && git reset --hard).
2. "build:dev": "cross-env BUILD_TYPE=dev webpack", matching the two neighbouring scripts.
3. Either quote the three Jest patterns as scratch-storage does, or use plain test/unit,
   test/integration, test/smoke, which Jest matches on every platform because it normalises
   separators before applying the regex.

Bugs 2 and 3 are collapsed into one commit since they touch the same file.