fix(detectors): handle arrays when checking for openapi and swagger

pkg/detectors/openapi/.snapshots/TestOtherjson

@@ -0,0 +1 @@
+([]*detections.Detection) <nil>

pkg/detectors/openapi/openapi.go

@@ -1,6 +1,7 @@
 package openapi
 
 import (
+	"bytes"
 	"encoding/json"
 	"io/ioutil"
 
@@ -73,6 +74,10 @@ func getFileType(file *file.FileInfo) (detectors.OpenAPIFileType, error) {
 
 	var version version
 	if ext == ".json" {
+		if isArray(input) { // fallback to json|yaml detector
+			return "", nil
+		}
+
 		err := json.Unmarshal(input, &version)
 		if err != nil {
 			return detectors.OpenAPIFileType(""), err
@@ -109,3 +114,7 @@ func getFileType(file *file.FileInfo) (detectors.OpenAPIFileType, error) {
 	}
 
 }
+
+func isArray(input []byte) bool {
+	return bytes.HasPrefix(bytes.TrimSpace(input), []byte("["))
+}

pkg/detectors/openapi/openapi_test.go

@@ -40,3 +40,9 @@ func TestDetectorV2yaml(t *testing.T) {
 
 	cupaloy.SnapshotT(t, report.Detections)
 }
+
+func TestOtherjson(t *testing.T) {
+	report := testhelper.Extract(t, filepath.Join("testdata", "arrayjson"), registrations, detectorType)
+
+	cupaloy.SnapshotT(t, report.Detections)
+}

pkg/detectors/openapi/testdata/arrayjson/packages.json

@@ -0,0 +1,14 @@
+[
+  {
+    "name": "actioncable",
+    "package_type": "rubygems",
+    "fallback_state": "reviewed",
+    "fallback_detected_data_store_technology": null
+  },
+  {
+    "name": "actionmailbox",
+    "package_type": "rubygems",
+    "fallback_state": "reviewed",
+    "fallback_detected_data_store_technology": null
+  }
+]