Add a CI check for file formatting

.github/file_format.sh

@@ -0,0 +1,49 @@
+#!/usr/bin/env bash
+
+# This script ensures proper POSIX text file formatting and a few other things.
+
+set -uo pipefail
+IFS=$'\n\t'
+
+# Loops through all text files tracked by Git.
+git grep -zIl '' |
+while IFS= read -rd '' f; do
+    # Ensure that files are UTF-8 formatted.
+    recode UTF-8 "$f" 2> /dev/null
+    # Ensure that files have LF line endings and do not contain a BOM.
+    dos2unix "$f" 2> /dev/null
+    # Remove trailing space characters and ensures that files end
+    # with newline characters. -l option handles newlines conveniently.
+    perl -i -ple 's/\s*$//g' "$f"
+    # Remove the character sequence "== true" if it has a leading space.
+    perl -i -pe 's/\x20== true//g' "$f"
+    # We don't want to change lines around braces in godot/tscn files.
+    if [[ "$f" == *"godot" ]]; then
+        continue
+    elif [[ "$f" == *"tscn" ]]; then
+        continue
+    fi
+    # Disallow empty lines after the opening brace.
+    sed -z -i 's/\x7B\x0A\x0A/\x7B\x0A/g' "$f"
+    # Disallow some empty lines before the closing brace.
+    sed -z -i 's/\x0A\x0A\x7D/\x0A\x7D/g' "$f"
+done
+
+git diff > patch.patch
+FILESIZE="$(stat -c%s patch.patch)"
+MAXSIZE=5
+
+# If no patch has been generated all is OK, clean up, and exit.
+if (( FILESIZE < MAXSIZE )); then
+    printf "Files in this commit comply with the formatting rules.\n"
+    rm -f patch.patch
+    exit 0
+fi
+
+# A patch has been created, notify the user, clean up, and exit.
+printf "\n*** The following differences were found between the code "
+printf "and the formatting rules:\n\n"
+cat patch.patch
+printf "\n*** Aborting, please fix your commit(s) with 'git commit --amend' or 'git rebase -i <hash>'\n"
+rm -f patch.patch
+exit 1

.github/workflows/static_checks.yml

@@ -0,0 +1,19 @@
+name: Static Checks
+on: [push, pull_request]
+
+jobs:
+  format:
+    name: File formatting (file_format.sh)
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: |
+          sudo apt-get update -qq
+          sudo apt-get install -qq dos2unix recode
+
+      - name: File formatting checks (file_format.sh)
+        run: |
+          bash ./.github/file_format.sh