fix: Ensure parsed configs have CRLF to LF corrected (where possible)

Likewise, this runtime fix was only covering two config files. It now applies to all callers of this method.

target/scripts/helpers/accounts.sh

@@ -19,9 +19,6 @@ function _create_accounts() {
   _create_masters
 
   if [[ -f ${DATABASE_ACCOUNTS} ]]; then
-    _log 'trace' "Checking file line endings"
-    sed -i 's|\r||g' "${DATABASE_ACCOUNTS}"
-
     _log 'trace' "Regenerating postfix user list"
     echo "# WARNING: this file is auto-generated. Modify ${DATABASE_ACCOUNTS} to edit the user list." > /etc/postfix/vmailbox
 
@@ -154,9 +151,6 @@ function _create_masters() {
 
   local DATABASE_DOVECOT_MASTERS='/tmp/docker-mailserver/dovecot-masters.cf'
   if [[ -f ${DATABASE_DOVECOT_MASTERS} ]]; then
-    _log 'trace' "Checking file line endings"
-    sed -i 's|\r||g' "${DATABASE_DOVECOT_MASTERS}"
-
     _log 'trace' "Regenerating dovecot masters list"
 
     chown dovecot:dovecot "${DOVECOT_MASTERDB_FILE}"

target/scripts/helpers/utils.sh

@@ -17,18 +17,33 @@ function _escape_for_sed() {
 # Returns input after filtering out lines that are:
 # empty, white-space, comments (`#` as the first non-whitespace character)
 function _get_valid_lines_from_file() {
+  _convert_crlf_to_lf_if_necessary "${1}"
   _append_final_newline_if_missing "${1}"
+
   grep --extended-regexp --invert-match "^\s*$|^\s*#" "${1}" || true
 }
 
+# This is to sanitize configs from users that unknowingly introduced CRLF:
+function _convert_crlf_to_lf_if_necessary() {
+  if [[ $(file "${1}") =~ 'CRLF' ]]; then
+    _log 'warn' "${1} contains CRLF line-endings."
+
+    if [[ -w "${1}" ]]; then
+      _log 'debug' 'Converting CRLF to LF'
+      sed -i 's|\r||g' "${1}"
+    fi
+  fi
+}
+
+# This is to sanitize configs from users that unknowingly removed the end-of-file LF:
 function _append_final_newline_if_missing() {
   # Correctly detect a missing final newline and fix it:
   # https://stackoverflow.com/questions/38746/how-to-detect-file-ends-in-newline#comment82380232_25749716
   # https://unix.stackexchange.com/questions/31947/how-to-add-a-newline-to-the-end-of-a-file/441200#441200
   # https://unix.stackexchange.com/questions/159557/how-to-non-invasively-test-for-write-access-to-a-file
-  if [[ $(tail -c1 "${1}" | wc -l) -gt 0 ]]; then
+  if [[ $(tail -c1 "${1}" | wc -l) -eq 0 ]]; then
     # Avoid fixing when the destination is read-only:
-    if [[ test -w "${1}" ]]; then
+    if [[ -w "${1}" ]]; then
       printf '\n' >> "${1}"
 
       _log 'warn' "${1} was missing a final newline. This has been fixed."