sf-webpack-encore-test-apps

name	sf-webpack-encore-test-apps
description	Add or modify a CI test app under test_apps/ in the symfony/webpack-encore repo. Enforces the lowest-peers naming convention, exact version pins, and matrix-entry layout in testing_apps.yml.

When to Activate

Trigger when the user, working inside the symfony/webpack-encore repository, asks to:

• "rajoute/ajoute une testing-app", "add a testing app", "new test_apps/…"
• create a new directory under test_apps/ to exercise a specific peer dependency edge (TypeScript version, Svelte version, fork-ts-checker branch, webpack-cli major, etc.)
• update the CI matrix in .github/workflows/testing_apps.yml

Do not activate for changes inside other repos, or for app code that has nothing to do with test_apps/.

Core Rules

1. Folder name MUST use the lowest-peers- prefix (e.g. lowest-peers-typescript5, lowest-peers-svelte4). Never create a top-level test_apps/<topic>/ without the prefix unless the user explicitly overrides.
2. devDependencies versions MUST be EXACT — no ^, no ~, no ranges (e.g. "typescript": "5.0.0", not "^5.0.0").
3. Pinned version = lowest end of the matching peerDependencies range in the root package.json of the repo. Example: ^5.0.0 || ^6.0.0 → pin 5.0.0.
4. Do NOT add ts-loader or fork-ts-checker-webpack-plugin when the app exercises enableBabelTypeScriptPreset() — that API is mutually exclusive with enableTypeScriptLoader() / enableForkedTypeScriptTypesChecking() (see lib/WebpackConfig.js).
5. Always generate pnpm-lock.yaml with pnpm install --ignore-workspace and commit it. CI runs with --frozen-lockfile and setup-node caches by ${working_directory}/pnpm-lock.yaml.
6. Mirror an existing lowest-peers-* app as the template instead of writing from scratch — that's how layout, scripts, and lockfile flags stay consistent.

File Structure

Each test_apps/lowest-peers-<topic>/ directory contains:

lowest-peers-<topic>/
├── .gitignore           # exactly: public/build
├── README.md            # short blurb + install/usage block
├── assets/
│   └── app.<ext>        # .ts for TypeScript apps, .js otherwise
├── package.json         # exact-pin devDependencies, type: module
├── pnpm-lock.yaml       # generated, committed
├── tsconfig.json        # only for TypeScript apps
└── webpack.config.js    # ESM, imports @symfony/webpack-encore

Templates

package.json (TypeScript + Babel preset example)

{
  "license": "UNLICENSED",
  "private": true,
  "type": "module",
  "scripts": {
    "encore": "encore"
  },
  "devDependencies": {
    "@babel/core": "7.17.0",
    "@babel/preset-env": "7.16.0",
    "@babel/preset-typescript": "7.0.0",
    "typescript": "5.0.0",
    "webpack": "5.82.0",
    "webpack-cli": "6.0.0"
  }
}

webpack.config.js

import Encore from '@symfony/webpack-encore';

Encore
    .setOutputPath('public/build/')
    .setPublicPath('/build')
    .enableSingleRuntimeChunk()
    .enableBabelTypeScriptPreset()
    .addEntry('app', './assets/app.ts')
;

export default await Encore.getWebpackConfig();

Matrix entry in .github/workflows/testing_apps.yml

Insert next to sibling lowest peers (…) entries:

                    - name: lowest peers (<topic short label>)
                      pkg_manager: pnpm
                      working_directory: test_apps/lowest-peers-<topic>
                      script: |
                          pnpm install --ignore-workspace --frozen-lockfile
                          pnpm add --ignore-workspace --save-dev ../../webpack-encore.tgz
                          pnpm run encore dev
                          pnpm run encore production

The --ignore-workspace flag is mandatory for every lowest-peers-* entry — without it pnpm pulls hoisted versions from the repo root and the lowest-peers contract breaks.

README.md

# Testing app: lowest-peers-<topic>

Pins `<package>@<version>` (plus core peer deps) to their lowest supported versions declared in Encore's `peerDependencies`. <one-line scope sentence>.

## Installation

\`\`\`shell
$ (cd ../..; pnpm pack --out webpack-encore.tgz)
$ pnpm install --ignore-workspace --frozen-lockfile
$ pnpm add --ignore-workspace --save-dev ../../webpack-encore.tgz
\`\`\`

## Usage

\`\`\`
$ pnpm run encore dev
$ pnpm run encore production
\`\`\`

Workflow

1. Mirror. Pick the closest existing test_apps/lowest-peers-* app and copy its layout (tsconfig.json, assets/app.*, .gitignore, README.md).
2. Pin versions. Open the root package.json, read peerDependencies, and write the lowest bound as an exact pin into the new package.json. No ranges.
3. Config Encore. Adjust webpack.config.js to call only the methods the app exercises. Respect mutual-exclusion rules between Encore APIs.
4. Generate the lockfile. cd test_apps/lowest-peers-<topic> && pnpm install --ignore-workspace. Commit pnpm-lock.yaml.
5. Smoke-test locally. From inside the app directory: (cd ../..; pnpm pack --out webpack-encore.tgz) && pnpm add --ignore-workspace --save-dev ../../webpack-encore.tgz && pnpm run encore dev && pnpm run encore production. Inspect public/build/app.js to confirm the build emitted JS (no residual TS syntax, no errors).
6. Register in CI. Add a matrix entry in .github/workflows/testing_apps.yml next to the sibling lowest peers (…) entries, using the script block above.
7. Update memory if a new convention emerges (scope of versions covered, new Encore API exercised, etc.).

Examples

User: "Rajoute une testing-app TypeScript 5 utilisant le preset Babel TypeScript"

1. Mirror test_apps/lowest-peers-typescript-fork9/ (same TS toolchain, drop fork-ts-checker / ts-loader).
2. Create test_apps/lowest-peers-typescript5/ with exact pins matching root peerDependencies lowest bounds (typescript: 5.0.0, @babel/preset-typescript: 7.0.0, etc.).
3. webpack.config.js calls enableBabelTypeScriptPreset() (mutually exclusive with enableTypeScriptLoader()).
4. Generate pnpm-lock.yaml via pnpm install --ignore-workspace.
5. Add matrix entry lowest peers (TypeScript 5 with Babel preset) in .github/workflows/testing_apps.yml, inserted alongside the other lowest peers (TypeScript + …) entries.

User: "Bump the lowest-peers webpack-cli to v7"

Do NOT bump the existing lowest-peers-webpack-cli6 app — create a sibling lowest-peers-webpack-cli7 with the new exact pin. The "lowest" apps lock the lower bound; covering a new major needs a new app, not an in-place edit.