Add CI checks for file formatting and style checks

misc/scripts/file_format.sh

@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+
+# This script ensures proper POSIX text file formatting and a few other things.
+# This is supplementary to black_format.sh, but should be run before it.
+
+# We need dos2unix and recode.
+if [ ! -x "$(command -v dos2unix)" -o ! -x "$(command -v recode)" ]; then
+    printf "Install 'dos2unix' and 'recode' to use this script.\n"
+fi
+
+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"
+done
+
+git diff > patch.patch
+
+# If no patch has been generated all is OK, clean up, and exit.
+if [ ! -s patch.patch ] ; 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