feat: add dart_frog_lint package

.github/workflows/dart_frog_lint.yaml

@@ -0,0 +1,53 @@
+name: dart_frog_lint
+
+on:
+  pull_request:
+    paths:
+      - ".github/workflows/dart_frog_lint.yaml"
+      - "packages/dart_frog_lint/example/**"
+      - "packages/dart_frog_lint/lib/**"
+      - "packages/dart_frog_lint/test/**"
+      - "packages/dart_frog_lint/pubspec.yaml"
+  push:
+    branches:
+      - main
+    paths:
+      - ".github/workflows/dart_frog_lint.yaml"
+      - "packages/dart_frog_lint/example/**"
+      - "packages/dart_frog_lint/lib/**"
+      - "packages/dart_frog_lint/test/**"
+      - "packages/dart_frog_lint/pubspec.yaml"
+
+jobs:
+  build:
+    uses: VeryGoodOpenSource/very_good_workflows/.github/workflows/dart_package.yml@v1
+    with:
+      working_directory: packages/dart_frog
+
+  custom_lint:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: packages/dart_frog_lint
+
+    steps:
+      # Bootstrap project
+      - uses: actions/[email protected]
+        with:
+          fetch-depth: 2
+      - uses: subosito/[email protected]
+      - name: Add pub cache bin to PATH
+        run: echo "$HOME/.pub-cache/bin" >> $GITHUB_PATH
+      - name: Add pub cache to PATH
+        run: echo "PUB_CACHE="$HOME/.pub-cache"" >> $GITHUB_ENV
+      - name: Install dependencies
+        run: flutter pub get
+
+      # Finally do some checks
+      - name: Run custom_lint
+        run: dart run custom_lint
+
+  pana:
+    uses: VeryGoodOpenSource/very_good_workflows/.github/workflows/pana.yml@v1
+    with:
+      working_directory: packages/dart_frog

packages/dart_frog_lint/.gitignore

@@ -0,0 +1,10 @@
+# See https://www.dartlang.org/guides/libraries/private-files
+
+# Files and directories created by pub
+.dart_tool/
+.packages
+build/
+pubspec.lock
+
+# Test related files
+coverage/

packages/dart_frog_lint/CHANGELOG.md

@@ -0,0 +1,3 @@
+# Unreleased
+
+Initial release

packages/dart_frog_lint/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2022 Very Good Ventures
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/dart_frog_lint/README.md

@@ -0,0 +1,230 @@
+Dart_frog_lint is a developer tool for users of dart_frog, to help spot common mistakes.  
+It helps verify that file conventions are properly respected.
+
+## Table of content
+
+- [Table of content](#table-of-content)
+- [Installing dart\_frog\_lint](#installing-dart_frog_lint)
+- [Enabling/disabling lints.](#enablingdisabling-lints)
+  - [Disable one specific rule](#disable-one-specific-rule)
+  - [Disable all lints by default](#disable-all-lints-by-default)
+- [Running dart\_frog\_lint in the terminal/CI](#running-dart_frog_lint-in-the-terminalci)
+- [All the lints](#all-the-lints)
+  - [dart\_frog\_entrypoint](#dart_frog_entrypoint)
+  - [dart\_frog\_middleware](#dart_frog_middleware)
+  - [dart\_frog\_route](#dart_frog_route)
+
+## Installing dart_frog_lint
+
+Dart_frog_lint is implemented using [custom_lint]. As such, it uses custom_lint's installation logic.  
+Long story short:
+
+- Add both dart_frog_lint and custom_lint to your `pubspec.yaml`:
+  ```yaml
+  dev_dependencies:
+    custom_lint:
+    dart_frog_lint:
+  ```
+- Enable `custom_lint`'s plugin in your `analysis_options.yaml`:
+
+  ```yaml
+  analyzer:
+    plugins:
+      - custom_lint
+  ```
+
+## Enabling/disabling lints.
+
+By default when installing dart_frog_lint, most of the lints will be enabled.
+To change this, you have a few options.
+
+### Disable one specific rule
+
+You may dislike one of the various lint rules offered by dart_frog_lint.
+In that event, you can explicitly disable this lint rule for your project
+by modifying the `analysis_options.yaml`
+
+```yaml
+analyzer:
+  plugins:
+    - custom_lint
+
+custom_lint:
+  rules:
+    # Explicitly disable one lint rule
+    - dart_frog_request: false
+```
+
+Note that you can both enable and disable lint rules at once.
+This can be useful if your `analysis_options.yaml` includes another one:
+
+```yaml
+include: path/to/another/analysis_options.yaml
+analyzer:
+  plugins:
+    - custom_lint
+
+custom_lint:
+  rules:
+    # Enable one rule
+    - dart_frog_middleware
+    # Disable another
+    - dart_frog_request: false
+```
+
+### Disable all lints by default
+
+Instead of having all lints on by default and manually disabling lints of your choice,
+you can switch to the opposite logic:  
+Have lints off by default, and manually enable lints.
+
+This can be done in your `analysis_options.yaml` with the following:
+
+```yaml
+analyzer:
+  plugins:
+    - custom_lint
+
+custom_lint:
+  # Forcibly disable lint rules by default
+  enable_all_lint_rules: false
+  rules:
+    # You can now enable one specific rule in the "rules" list
+    - dart_frog_middleware
+```
+
+## Running dart_frog_lint in the terminal/CI
+
+Custom lint rules created by dart_frog_lint may not show-up in `dart analyze`.
+To fix this, you can run a custom command line: `custom_lint`.
+
+Since your project should already have custom_lint installed
+(cf [installing dart_frog_lint](#installing-dart_frog_lint)), then you should be
+able to run:
+
+```sh
+dart run custom_lint
+```
+
+Alternatively, you can globally install `custom_lint`:
+
+```sh
+# Install custom_lint for all projects
+dart pub global activate custom_lint
+# run custom_lint's command line in a project
+custom_lint
+```
+
+## All the lints
+
+### dart_frog_entrypoint
+
+The `dart_frog_entrypoint` lint checks that `main.dart` files contain a
+valid `run` function. See also [Creating a custom entrypoint](https://dartfrog.vgv.dev/docs/advanced/custom_entrypoint).
+
+**Good**:
+
+```dart
+// main.dart
+Future<HttpServer> run(Handler handler, InternetAddress ip, int port) {
+  // TODO
+}
+```
+
+**Bad**:
+
+```dart
+// An empty main.dart file
+// The file must contain a top-level function named "run"
+```
+
+```dart
+// main.dart
+
+// A "run" function is present, but the return value or parameters are incorrect
+void run() {}
+```
+
+### dart_frog_middleware
+
+The `dart_frog_middleware` lint checks that `routes/*_middleware.dart` files contain a
+valid `middleware` function. See also [Middleware](https://dartfrog.vgv.dev/docs/basics/middleware).
+
+**Good**:
+
+```dart
+// routes/my_middleware.dart
+Handler middleware(Handler handler) {
+  return (context) async {
+    // TODO
+  };
+}
+```
+
+**Bad**:
+
+```dart
+// routes/my_middleware.dart
+// The file must contain a valid top-level "middleware" function
+```
+
+```dart
+// routes/my_middleware.dart
+// The file must contain a valid top-level "middleware" function
+
+// A "middleware" function is present, but the return value or parameters are incorrect
+void middleware() {}
+```
+
+### dart_frog_route
+
+The `dart_frog_route` lint checks that `routes/*.dart` files contain a
+valid `onRequest` function. See also [Routes](https://dartfrog.vgv.dev/docs/basics/routes).
+
+**Good**:
+
+```dart
+// routes/hello.dart
+Response onRequest(RequestContext context) {
+  // TODO
+}
+```
+
+```dart
+// routes/posts/[id].dart
+// Dynamic routes are supported too
+Response onRequest(RequestContext context, String id) {
+  // TODO
+}
+```
+
+```dart
+// routes/example.dart
+// Routes can return a Future<T>
+Future<Response> onRequest(RequestContext context) async {
+  // TODO
+}
+```
+
+**Bad**:
+
+```dart
+//  routes/hello.dart
+// The file must contain a valid top-level "onRequest" function
+```
+
+```dart
+// routes/hello.dart
+// An "onRequest" function is present, but the return value or parameters are incorrect
+void onRequest() {}
+```
+
+```dart
+// routes/posts/[id].dart
+// The route is a dynamic route, but onRequest doesn't receive the correct number of parameters.
+Response onRequest(RequestContext context) {
+    // TODO
+}
+```
+
+[custom_lint]: https://pub.dev/packages/custom_lint

packages/dart_frog_lint/analysis_options.yaml

@@ -0,0 +1 @@
+include: package:very_good_analysis/analysis_options.4.0.0.yaml

packages/dart_frog_lint/example/.gitignore

@@ -0,0 +1 @@
+custom_lint.log

packages/dart_frog_lint/example/analysis_options.yaml

@@ -0,0 +1,7 @@
+include: ../analysis_options.yaml
+analyzer:
+  plugins:
+    - custom_lint
+linter:
+  rules:
+    file_names: false

packages/dart_frog_lint/example/lib/out.dart

@@ -0,0 +1 @@
+// An empty file for checking that routes lints don't trigger on lib folders

packages/dart_frog_lint/example/main.dart

@@ -0,0 +1,7 @@
+import 'dart:io';
+
+import 'package:dart_frog/dart_frog.dart';
+
+Future<HttpServer> run(Handler handler, InternetAddress ip, int port) {
+  throw UnimplementedError();
+}

packages/dart_frog_lint/example/pubspec.yaml

@@ -0,0 +1,15 @@
+name: dart_frog_lint_example
+version: 0.0.1
+publish_to: "none"
+
+environment:
+  sdk: ">=2.17.0 <3.0.0"
+
+dependencies:
+  dart_frog:
+    path: ../../dart_frog
+
+dev_dependencies:
+  dart_frog_lint:
+    path: ..
+  very_good_analysis: ^4.0.0

packages/dart_frog_lint/example/routes/dart_frog_middleware/invalid_parameter_middleware.dart

@@ -0,0 +1,6 @@
+import 'package:dart_frog/dart_frog.dart';
+
+// expect_lint: dart_frog_middleware
+Handler middleware(int handler) {
+  throw UnimplementedError();
+}

packages/dart_frog_lint/example/routes/dart_frog_middleware/invalid_return_middleware.dart

@@ -0,0 +1,6 @@
+import 'package:dart_frog/dart_frog.dart';
+
+// expect_lint: dart_frog_middleware
+String middleware(Handler handler) {
+  throw UnimplementedError();
+}