chore: adjust comment about MAX_COMMITS_TO_CHECK

Reviewed-on: #9
Reviewed-by: Artur Neumann <artur@jankaritech.eu>

hooks/validate.sh

@@ -42,6 +42,7 @@ if [[ ! -d "$DIR" ]]; then DIR="$PWD"; fi
 . "$DIR/timestamping"
 
 declare -i MINVERSION=$TIMESTAMPING_VERSION
+declare -i MAX_COMMITS_TO_CHECK=0
 declare -A PROCESSED_COMMIT
 
 while [[ $# -gt 0 ]]; do
@@ -62,6 +63,16 @@ while [[ $# -gt 0 ]]; do
       shift # past argument
       shift # past value
       ;;
+    -max|--maxcommits)
+      INTEGER_REGEX='^[0-9]+$'
+      if ! [[ "$2" =~ $INTEGER_REGEX ]]; then
+        echo_error "$KEY: expected positive integer"
+        exit 1
+      fi
+      MAX_COMMITS_TO_CHECK="$2"
+      shift # past argument
+      shift # past value
+      ;;
     -v|--verbose)
       OUT_STREAM=/dev/stdout
       shift # past argument
@@ -300,6 +311,13 @@ validate_commit() {
 # param1: commit hash
 # returns: 0 if the validation of the commit and all its ancestors succeeded
 validate_commit_and_parents() {
+  # If MAX_COMMITS_TO_CHECK is zero (or a negative number) then that is understood as "infinity".
+  # So finish if we have reached the limit, and if the limit is not "infinity".
+  NUM_COMMITS_CHECKED=${#PROCESSED_COMMIT[@]}
+  if [[ ${NUM_COMMITS_CHECKED} -ge ${MAX_COMMITS_TO_CHECK} ]] && [[ ${MAX_COMMITS_TO_CHECK} -ge 1 ]]; then
+    # enough commits have already been checked, so return early
+    return 0;
+  fi
   local COMMIT_HASH="$1"
   log "validate_commit_and_parents for $COMMIT_HASH"
 
@@ -307,6 +325,7 @@ validate_commit_and_parents() {
   if ! validate_commit "$COMMIT_HASH"; then
     ALL_PASSED=false
   fi
+  NUM_COMMITS_CHECKED=${#PROCESSED_COMMIT[@]}
   local PARENTS=$(git cat-file -p "$COMMIT_HASH" | awk '/^$/{exit} /parent/ {print}' | sed 's/parent //')
   #iterate over all parents of commit
   if [ ! -z "$PARENTS" ]; then