check_formalities: escape LaTeX special characters in output

src/check_formalities.sh

@@ -188,15 +188,22 @@ output_skip() {
 output_split_fail() {
 	split_fail "$1" "$2" "${INDENT_TERM}"
 	[ -f "$GITHUB_OUTPUT" ] || return
+	local part1 part2
+	part1="$(escape_latex "${2:0:$1}")"
+	part2="$(escape_latex "${2:$1}")"
 	printf "${INDENT_MD}\$\\\textsf{%s\\color{red}{%s}}\$\n" \
-		"${2:0:$1}" "${2:$1}" >> "$GITHUB_OUTPUT"
+		"$part1" "$part2" >> "$GITHUB_OUTPUT"
 }
 
 output_split_fail_ex() {
 	split_fail_ex "$1" "$2" "$3" "${INDENT_TERM}"
 	[ -f "$GITHUB_OUTPUT" ] || return
+	local part1 part2 part3
+	part1="$(escape_latex "${3:0:$1}")"
+	part2="$(escape_latex "${3:$1:$(($2 - $1))}")"
+	part3="$(escape_latex "${3:$2}")"
 	printf "${INDENT_MD}\$\\\textsf{%s\\color{yellow}{%s}\\color{red}{%s}}\$\n" \
-		"${3:0:$1}" "${3:$1:$(($2 - $1))}" "${3:$2}" >> "$GITHUB_OUTPUT"
+		"$part1" "$part2" "$part3" >> "$GITHUB_OUTPUT"
 }
 
 # shellcheck disable=SC2329

src/helpers.sh

@@ -58,3 +58,44 @@ status_fail() {
 status_skip() {
 	status 39 skip "$1"
 }
+
+# Escapes special characters in the given text to be safe for inclusion in LaTeX
+# output.
+escape_latex() {
+	local text="$1"
+
+	# Placeholders for characters that need special handling
+	local bs='LATEXESCAPEBACKSLASH'
+	local crt='LATEXESCAPECARET'
+	local rcb='LATEXESCAPERCB'
+	local tld='LATEXESCAPETILDE'
+
+	# Replacement strings (stored in variables to avoid bash parsing issues with
+	# } in replacement strings)
+	local r_bs='\textbackslash{}'
+	local r_crt='\textasciicircum{}'
+	local r_rcb='\}'
+	local r_tld='\textasciitilde{}'
+
+	# First, replace characters that need placeholders
+	text="${text//\\/$bs}"
+	text="${text//^/$crt}"
+	text="${text//\}/$rcb}"
+	text="${text//\~/$tld}"
+
+	# Escape simple characters
+	text="${text//_/\\_}"
+	text="${text//\$/\\$}"
+	text="${text//&/\\&}"
+	text="${text//%/\\%}"
+	text="${text//#/\\#}"
+	text="${text//\{/\\{}"
+
+	# Replace placeholders with actual LaTeX commands
+	text="${text//$bs/$r_bs}"
+	text="${text//$crt/$r_crt}"
+	text="${text//$rcb/$r_rcb}"
+	text="${text//$tld/$r_tld}"
+
+	echo "$text"
+}

src/test.sh

@@ -454,6 +454,18 @@ define \
 		Signed-off-by: Good Author <good.author@example.com>
 	EOF
 
+define \
+	-test          'LaTeX special chars' \
+	-expected      '0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 3' \
+	-author        'Good Author' \
+	-email         'good.author@example.com' \
+	-subject       'package: stress test latex escaping' \
+	-body          <<-'EOF'
+		This line is intentionally made very long to trigger the body length check warning or error so we can test escaping of _ & % $ # { } \ ^ ~
+
+		Signed-off-by: Good Author <good.author@example.com>
+	EOF
+
 cleanup() {
 	if [ -d "$REPO_DIR" ]; then
 		[ -z "$PARALLEL_WORKER" ] && echo "Cleaning up temporary directory '$REPO_DIR'"