Add a pre commit hook to lint code

This uses pre-commit [1] to check patches are well formed and run
several linters on them. We currently do some boring things (check files
are syntactically valid) as well as some project-specific ones:
 - Run illuaminate on the Lua files
 - Run checkstyle on Java

[1]: https://pre-commit.com/

.editorconfig

@@ -16,6 +16,3 @@ indent_size = 2
 
 [*.yml]
 indent_size = 2
-
-[*.properties]
-insert_final_newline = false

.github/workflows/main-ci.yml

@@ -23,10 +23,15 @@ jobs:
         restore-keys: |
           ${{ runner.os }}-gradle-
 
+    - name: Disable Gradle daemon
+      run: |
+        mkdir -p ~/.gradle
+        echo "org.gradle.daemon=false" >> ~/.gradle/gradle.properties
+
     - name: Build with Gradle
       run: |
-        ./gradlew assemble --no-daemon || ./gradlew assemble --no-daemon
-        ./gradlew downloadAssets --no-daemon || ./gradlew downloadAssets --no-daemon
+        ./gradlew assemble || ./gradlew assemble
+        ./gradlew downloadAssets || ./gradlew downloadAssets
         ./gradlew build
 
     - name: Upload Jar
@@ -39,15 +44,14 @@ jobs:
       run: bash <(curl -s https://codecov.io/bash)
       continue-on-error: true
 
-    - name: Generate Java documentation stubs
-      run: ./gradlew luaJavadoc --no-daemon
-
-    - name: Lint Lua code
+    - name: Cache pre-commit
+      uses: actions/cache@v2
+      with:
+        path: ~/.cache/pre-commit
+        key: ${{ runner.os }}-pre-commit-${{ hashFiles('config/pre-commit/config.yml') }}
+        restore-keys: |
+          ${{ runner.os }}-pre-commit-
+    - name: Run linters
       run: |
-        test -d bin || mkdir bin
-        test -f bin/illuaminate || wget -q -Obin/illuaminate https://squiddev.cc/illuaminate/linux-x86-64/illuaminate
-        chmod +x bin/illuaminate
-        bin/illuaminate lint
-
-    - name: Check whitespace
-      run: python3 tools/check-lines.py
+        pip install pre-commit
+        pre-commit run --config config/pre-commit/config.yml --show-diff-on-failure --all --color=always

config/pre-commit/config.yml

@@ -0,0 +1,48 @@
+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
+repos:
+- repo: https://github.com/pre-commit/pre-commit-hooks
+  rev: v3.2.0
+  hooks:
+  - id: trailing-whitespace
+  - id: end-of-file-fixer
+  - id: check-merge-conflict
+
+  # Quick syntax checkers
+  - id: check-xml
+  - id: check-yaml
+  - id: check-toml
+  - id: check-json
+    exclude: "tsconfig\\.json$"
+
+- repo: https://github.com/editorconfig-checker/editorconfig-checker.python
+  rev: 2.3.5
+  hooks:
+  - id: editorconfig-checker
+    args: ['-disable-indentation']
+    exclude: "^(.*\\.(bat)|LICENSE)$"
+
+- repo: local
+  hooks:
+  - id: checkstyle
+    name: Check Java codestyle
+    files: ".*\\.java$"
+    language: system
+    entry: ./gradlew checkstyleMain checkstyleTest
+    pass_filenames: false
+    require_serial: true
+  - id: illuaminate
+    name: Check Lua code
+    files: ".*\\.(lua|java|md)"
+    language: script
+    entry: config/pre-commit/illuaminate-lint.sh
+    pass_filenames: false
+    require_serial: true
+
+exclude: |
+  (?x)^(
+    src/generated|
+    src/test/resources/test-rom/data/json-parsing/|
+    src/test/server-files/|
+    config/idea/
+  )

config/pre-commit/illuaminate-lint.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env sh
+set -e
+
+test -d bin || mkdir bin
+test -f bin/illuaminate || curl -s -obin/illuaminate https://squiddev.cc/illuaminate/linux-x86-64/illuaminate
+chmod +x bin/illuaminate
+
+./gradlew luaJavadoc
+bin/illuaminate lint

tools/check-lines.py

@@ -1,45 +0,0 @@
-import pathlib, sys
-
-problems = False
-
-# Skip images and files without extensions
-exclude = [
-    "*.png",
-    "**/data/json-parsing/*.json",
-    "**/computers/ids.json",
-]
-
-for path in pathlib.Path("src").glob("**/*"):
-    # Ideally we'd use generated as a glob, but .match("generated/**/*.json") doesn't work!
-    if path.is_dir() or path.suffix == "" or any(path.match(x) for x in exclude) or path.parts[1] == "generated":
-        continue
-
-    with path.open(encoding="utf-8") as file:
-        has_dos, has_trailing, first, count = False, False, 0, True
-        for i, line in enumerate(file):
-            if first:
-                first = False
-                if line.strip() == "":
-                    print("%s has empty first line" % path)
-
-            if len(line) >= 2 and line[-2] == "\r" and line[-1] == "\n" and not has_dos:
-                print("%s has contains '\\r\\n' on line %d" % (path, i + 1))
-                problems = has_dos = True
-
-            if len(line) >= 2 and line[-2] in " \t" and line[-1] == "\n" and not has_trailing:
-                print("%s has trailing whitespace on line %d" % (path, i + 1))
-                problems = has_trailing = True
-
-            if len(line) == 0 or line[-1] != "\n":
-                count = 0
-            elif line.strip() == "":
-                count += 1
-            else:
-                count = 1
-
-        if count != 1:
-            print("%s should have 1 trailing lines, but has %d" % (path, count))
-            problems = True
-
-if problems:
-    sys.exit(1)