Dynamically exclude "-by" trailers in regex

This commit refactors trailer handling by dynamically extracting all
"-by" suffix trailers. It constructs 'TRAILERS_BY_REGEX' to match these trailers automatically.Also, the awk script is updated to use
'TRAILERS_BY_REGEX'.

Co-authored-by: EricccTaiwan <[email protected]>
Change-Id: I55166d2ecad85e9e3371ff354cefb2c648b49919

Author: charliechiou

scripts/commit-msg.hook

@@ -154,29 +154,23 @@ build_commit_trailer_regex() {
   # Read custom trailer keys from git config and add them either to specials or trailers.
   # This loop reads lines matching 'trailer.*.key'.
   while read -r _ key; do
-    # Skip if key already exists in trailers or specials.
+    if [[ "$key" =~ -by$ ]]; then
+      trailers_by+=("$key")
+      continue
+    fi
+
     for each in "${trailers[@]}" "${specials[@]}"; do
-      if [ "$key" = "$each" ]; then
-        continue 2
-      fi
+      [[ "$key" == "$each" ]] && continue 2
     done
-    # If key ends with a separator character, add to specials; otherwise, to trailers.
+
     if [[ $key =~ [${separators}]$ ]]; then
       specials+=("$key")
     else
       trailers+=("$key")
     fi
   done < <(git config --get-regexp 'trailer.*.key')
 
-  # Read custom trailer keys again into the 'keys' array (if needed).
-  while IFS=. read -r _ key _; do
-    for each in "${keys[@]}"; do
-      if [ "$key" = "$each" ]; then
-        continue 2
-      fi
-    done
-    keys+=("$key")
-  done < <(git config --get-regexp 'trailer.*.key')
+  TRAILERS_BY_REGEX="^($(IFS='|'; echo "${trailers_by[*]}")):"
 
   # Begin constructing the regex.
   TRAILER_REGEX='^('
@@ -209,16 +203,6 @@ build_commit_trailer_regex() {
     TRAILER_REGEX="${TRAILER_REGEX%|})"
   fi
 
-  # Append additional keys.
-  if ((${#keys[@]} > 0)); then
-    TRAILER_REGEX+='|(('
-    for each in "${keys[@]}"; do
-      TRAILER_REGEX+="$each|"
-    done
-    # Use the second character of separators (if available) as a separator for keys.
-    TRAILER_REGEX="${TRAILER_REGEX%|})[${separators:1:1}[:blank:]])"
-  fi
-
   # End the regex.
   TRAILER_REGEX+=")"
 }
@@ -618,7 +602,7 @@ add_change_id() {
     other_footer = ""
 
     for (line = 1; line <= numlines; line++) {
-      if (match(tolower(footer[line]), /^(signed-off-by|acked-by|co-authored-by|reviewed-by|tested-by|suggested-by|reported-by):/)) {
+      if (match(tolower(footer[line]), TRAILERS_BY_REGEX)) {
         trailers = trailers footer[line] "\n"
       } else {
         other_footer = other_footer footer[line] "\n"