Exit in case output is set in args and action input

I decided to make this a hard error, because it keeps the entrypoint simple.

Fixes #201

.github/workflows/test.yml

@@ -101,6 +101,20 @@ jobs:
             cat "${{ env.CUSTOM_OUTPUT_DUMP_PATH }}"
           fi
 
+      - name: test output set in args and action input
+        id: output_set_in_args_and_action_input
+        uses: ./
+        with:
+          args: --output foo -
+          output: bar
+        continue-on-error: true
+
+      - name: test output set in args and action input should fail - validation
+        if: steps.output_set_in_args_and_action_input.outcome != 'failure'
+        run: |
+          echo "Output set in args and action input should have failed."
+          exit 1
+
       - name: test failIfEmpty - no links in input should fail the pipeline
         id: fail_if_empty_test
         uses: ./

entrypoint.sh

@@ -21,6 +21,12 @@ FORMAT=""
 # If `format` occurs in args, ignore the value from `INPUT_FORMAT`
 [[ "$ARGS" =~ "--format " ]] || FORMAT="--format ${INPUT_FORMAT}"
 
+# If `output` occurs in args and `INPUT_OUTPUT` is set, exit with an error 
+if [[ "$ARGS" =~ "--output " ]] && [ -n "${INPUT_OUTPUT:-}" ]; then
+    echo "Error: 'output' is set in args as well as in the action configuration. Please remove one of them."
+    exit 1
+fi
+
 # Execute lychee
 eval lychee ${FORMAT} --output ${LYCHEE_TMP} ${ARGS} 
 exit_code=$?