Add clang-tidy configuration and watch script for improved code quality checks

.clang-tidy

@@ -0,0 +1,28 @@
+---
+Checks: >
+  -*,
+  clang-analyzer-*,
+  bugprone-*,
+  cert-*,
+  cppcoreguidelines-*,
+  modernize-*,
+  performance-*,
+  portability-*,
+  readability-*,
+  -cppcoreguidelines-avoid-magic-numbers,
+  -readability-magic-numbers,
+  -modernize-use-trailing-return-type,
+  -cppcoreguidelines-owning-memory
+# WarningsAsErrors: "*"
+HeaderFilterRegex: "^(include|source)/"
+FormatStyle: none
+SystemHeaders: false
+CheckOptions:
+  - key: readability-identifier-naming.VariableCase
+    value: lower_case
+  - key: readability-identifier-naming.FunctionCase
+    value: lower_case
+  - key: readability-identifier-naming.ClassCase
+    value: CamelCase
+  - key: cppcoreguidelines-pro-bounds-pointer-arithmetic.AllowIncrementDecrementOperators
+    value: "true"

.vscode/settings.json

@@ -1,9 +1,12 @@
 {
+    "C_Cpp.intelliSenseEngine": "disabled",
     "files.associations": {
         "array": "cpp",
         "*.c": "c"
     },
     "clangd.arguments": [
+        "--background-index",
+        "--clang-tidy",
         "--query-driver=${env:DEVKITPRO}/devkitARM/bin/arm-none-eabi-*",
         "--compile-commands-dir=."
     ]

.vscode/tasks.json

@@ -69,6 +69,70 @@
       "command": "cd ${workspaceFolder} && if [ -d build ]; then cmake --build build --target clean; fi && if [ -d build-debug ]; then cmake --build build-debug --target clean; fi",
       "problemMatcher": [],
     },
+    {
+      "label": "clang-tidy (all)",
+      "type": "shell",
+      "command": "cd ${workspaceFolder} && mkdir -p .clang-tidy-db && sed 's/-mthumb-interwork//g' compile_commands.json > .clang-tidy-db/compile_commands.json && run-clang-tidy -p .clang-tidy-db '.*\\.(c|cc|cpp|cxx)$' -extra-arg=-isystem -extra-arg=/opt/devkitpro/devkitARM/arm-none-eabi/include/c++/15.2.0 -extra-arg=-isystem -extra-arg=/opt/devkitpro/devkitARM/arm-none-eabi/include/c++/15.2.0/arm-none-eabi -extra-arg=-isystem -extra-arg=/opt/devkitpro/devkitARM/arm-none-eabi/include/c++/15.2.0/backward -extra-arg=-isystem -extra-arg=/opt/devkitpro/devkitARM/lib/gcc/arm-none-eabi/15.2.0/include -extra-arg=-isystem -extra-arg=/opt/devkitpro/devkitARM/lib/gcc/arm-none-eabi/15.2.0/include-fixed -extra-arg=-isystem -extra-arg=/opt/devkitpro/devkitARM/arm-none-eabi/include",
+      "problemMatcher": [
+        {
+          "owner": "cpp",
+          "fileLocation": "absolute",
+          "pattern": [
+            {
+              "regexp": "^(.*):(\\d+):(\\d+):\\s+(warning|error|note):\\s+(.*?)(?:\\s+\\[.*\\])?$",
+              "file": 1,
+              "line": 2,
+              "column": 3,
+              "severity": 4,
+              "message": 5
+            }
+          ]
+        }
+      ],
+      "group": "test",
+      "presentation": {
+        "echo": true,
+        "reveal": "always",
+        "focus": false,
+        "panel": "dedicated",
+        "clear": true
+      }
+    },
+    {
+      "label": "clang-tidy (watch changed)",
+      "type": "shell",
+      "isBackground": true,
+      "command": "cd ${workspaceFolder} && bash tools/clang_tidy_watch.sh",
+      "problemMatcher": [
+        {
+          "owner": "cpp",
+          "fileLocation": "absolute",
+          "pattern": [
+            {
+              "regexp": "^(.*):(\\d+):(\\d+):\\s+(warning|error|note):\\s+(.*?)(?:\\s+\\[.*\\])?$",
+              "file": 1,
+              "line": 2,
+              "column": 3,
+              "severity": 4,
+              "message": 5
+            }
+          ],
+          "background": {
+            "activeOnStart": true,
+            "beginsPattern": "^TIDY-WATCH-BEGIN$",
+            "endsPattern": "^TIDY-WATCH-END$"
+          }
+        }
+      ],
+      "group": "test",
+      "presentation": {
+        "echo": true,
+        "reveal": "always",
+        "focus": false,
+        "panel": "dedicated",
+        "clear": true
+      }
+    },
     {
       "label": "run",
       "type": "shell",

CMakeLists.txt

@@ -22,6 +22,8 @@ include("${DEVKITPRO_CMAKE}")
 
 project(snakePlus LANGUAGES C CXX ASM)
 
+option(ENABLE_CLANG_TIDY "Enable clang-tidy checks" OFF)
+
 # Export compile_commands.json for tooling (clangd, IntelliSense, static analysis).
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
@@ -30,6 +32,24 @@ set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS ON)
 
+if(ENABLE_CLANG_TIDY)
+        find_program(CLANG_TIDY_EXE NAMES clang-tidy)
+        if(NOT CLANG_TIDY_EXE)
+                message(FATAL_ERROR "ENABLE_CLANG_TIDY is ON, but clang-tidy was not found")
+        endif()
+
+        set(CMAKE_C_CLANG_TIDY
+                ${CLANG_TIDY_EXE}
+                --header-filter=^(include|source)/
+                --extra-arg=--target=arm-none-eabi
+        )
+        set(CMAKE_CXX_CLANG_TIDY
+                ${CLANG_TIDY_EXE}
+                --header-filter=^(include|source)/
+                --extra-arg=--target=arm-none-eabi
+        )
+endif()
+
 set(TARGET_NAME ${PROJECT_NAME})
 
 set(GAME_TITLE "Snake Plus")
@@ -122,6 +142,15 @@ target_compile_definitions(${TARGET_NAME} PRIVATE
 target_compile_options(${TARGET_NAME} PRIVATE
         -g
         -Wall
+        -Wextra
+        -Wpedantic
+        -Wconversion
+        -Wsign-conversion
+        -Wshadow
+        -Wformat=2
+        -Wundef
+        -Wnull-dereference
+        -Wimplicit-fallthrough
         -O3
         -marm
         -mthumb-interwork

tools/clang_tidy_watch.sh

@@ -0,0 +1,73 @@
+#!/usr/bin/env bash
+set -u
+
+ROOT_DIR="$(cd "$(dirname "$0")/.." && pwd)"
+cd "$ROOT_DIR" || exit 1
+
+EXTRA_ARGS=(
+  -extra-arg=-isystem
+  -extra-arg=/opt/devkitpro/devkitARM/arm-none-eabi/include/c++/15.2.0
+  -extra-arg=-isystem
+  -extra-arg=/opt/devkitpro/devkitARM/arm-none-eabi/include/c++/15.2.0/arm-none-eabi
+  -extra-arg=-isystem
+  -extra-arg=/opt/devkitpro/devkitARM/arm-none-eabi/include/c++/15.2.0/backward
+  -extra-arg=-isystem
+  -extra-arg=/opt/devkitpro/devkitARM/lib/gcc/arm-none-eabi/15.2.0/include
+  -extra-arg=-isystem
+  -extra-arg=/opt/devkitpro/devkitARM/lib/gcc/arm-none-eabi/15.2.0/include-fixed
+  -extra-arg=-isystem
+  -extra-arg=/opt/devkitpro/devkitARM/arm-none-eabi/include
+)
+
+rebuild_tidy_db() {
+  mkdir -p .clang-tidy-db
+  sed 's/-mthumb-interwork//g' compile_commands.json > .clang-tidy-db/compile_commands.json
+}
+
+collect_sources() {
+  find source include -type f \( -name '*.c' -o -name '*.cc' -o -name '*.cpp' -o -name '*.cxx' \) 2>/dev/null | sort
+}
+
+declare -A mtimes
+last_cc_mtime=""
+
+while true; do
+  if [[ ! -f compile_commands.json ]]; then
+    echo "Waiting for compile_commands.json (run CMake configure/build once)..."
+    sleep 2
+    continue
+  fi
+
+  cc_mtime="$(stat -c %Y compile_commands.json 2>/dev/null || echo 0)"
+  db_regenerated=0
+  if [[ "$cc_mtime" != "$last_cc_mtime" ]]; then
+    rebuild_tidy_db
+    last_cc_mtime="$cc_mtime"
+    db_regenerated=1
+  fi
+
+  mapfile -t files < <(collect_sources)
+  changed=()
+
+  for f in "${files[@]}"; do
+    m="$(stat -c %Y "$f" 2>/dev/null || echo 0)"
+    if [[ "${mtimes[$f]:-}" != "$m" ]]; then
+      changed+=("$f")
+      mtimes["$f"]="$m"
+    fi
+  done
+
+  if [[ $db_regenerated -eq 1 && ${#files[@]} -gt 0 ]]; then
+    changed=("${files[@]}")
+  fi
+
+  if [[ ${#changed[@]} -gt 0 ]]; then
+    echo "TIDY-WATCH-BEGIN"
+    for f in "${changed[@]}"; do
+      clang-tidy -quiet -p .clang-tidy-db "$f" "${EXTRA_ARGS[@]}" || true
+    done
+    echo "TIDY-WATCH-END"
+  fi
+
+  sleep 1
+done