Add require lock file input parameter

README.md

@@ -175,6 +175,7 @@ even more specific, you can specify a suffix to be added to the cache key via th
 :warning: Note: specifying a `custom-cache-key` will take precedence over the `custom-cache-suffix`.
 
 ### Fork and private repositories
+
 Sometimes it's needed to use the `repositories` key in your `composer.json` to pull in forks, PRs with patches or private repositories. In this case, your GitHub Action may start failing with a `Could not authenticate against github.com` error message. To solve this, you need to add a GitHub Personal Access token, and this bit to your Action configuration:
 ```yaml
 env:

action.yml

@@ -34,6 +34,11 @@ inputs:
     description: >-
       A custom suffix to add to the auto-generated cache key.
     required: false
+  require-lock-file:
+    description: >-
+      Require lock file for install command.
+    required: false
+    default: "false"
 
 runs:
   using: "composite"
@@ -91,4 +96,5 @@ runs:
           "${{ inputs.working-directory }}" \
           "${{ steps.php.outputs.path }}" \
           "${{ steps.composer.outputs.composer_command }}" \
-          "${{ steps.composer.outputs.lock }}"
+          "${{ steps.composer.outputs.lock }}" \
+          "${{ inputs.require-lock-file }}"

bin/composer_install.sh

@@ -6,6 +6,7 @@ working_directory="${3}"
 php_path="${4:-$(which php)}"
 composer_path="${5:-$(which composer)}"
 composer_lock="${6}"
+require_lock_file="${7}"
 
 composer_command="update"
 composer_options=("--no-interaction" "--no-progress" "--ansi")
@@ -18,6 +19,10 @@ esac
 
 # If there is no composer.lock file, then use the `update` command.
 if [ -z "${composer_lock}" ]; then
+    if [ "${composer_command}" == install ] && [ "${require_lock_file}" == true ]; then
+        echo "::error title=Composer Lock File Not Found::Unable to find 'composer.lock'"
+        exit 1
+    fi
     composer_command="update"
 fi