Tooling: lint new php files for strict types directive (take 2). (#48943)

This PRs is take two on expanding new php-files linting to validate strict types directive.

plugins/woocommerce/bin/lint-branch.sh

@@ -10,12 +10,21 @@
 
 baseBranch=${1:-"trunk"}
 
+# Lint changed php-files to match code style.
 changedFiles=$(git diff $(git merge-base HEAD $baseBranch) --relative --name-only --diff-filter=d -- '*.php')
-
-# Only complete this if changed files are detected.
-if [[ -z $changedFiles ]]; then
-    echo "No changed files detected."
-    exit 0
+if [[ -n $changedFiles ]]; then
+    composer exec phpcs-changed -- -s --git --git-base $baseBranch $changedFiles
 fi
 
-composer exec phpcs-changed -- -s --git --git-base $baseBranch $changedFiles
+# Lint new (excl. renamed) php-files to contain strict types directive.
+newFiles=$(git diff $(git merge-base HEAD $baseBranch) --relative --name-only --diff-filter=dmr -- '*.php')
+if [[ -n $newFiles ]]; then
+	passingFiles=$(find $newFiles -type f -exec grep -xl --regexp='declare(\s*strict_types\s*=\s*1\s*);' /dev/null {} +)
+	violatingFiles=$(grep -vxf <(printf "%s\n" $passingFiles | sort) <(printf "%s\n" $newFiles | sort))
+	if [[ -n violatingFiles ]]; then
+		redColoured='\033[0;31m'
+		printf "${redColoured}Following files are missing 'declare( strict_types = 1)' directive:\n"
+		printf "${redColoured}%s\n" $violatingFiles
+		exit 1
+	fi
+fi

plugins/woocommerce/changelog/add-41443-lint-strict-types-directive-for-new-files

@@ -0,0 +1,4 @@
+Significance: patch
+Type: dev
+
+Lint new PHP files for strict types directive