[release-1.14] Fix possible nil pointer dereference in event-dispatcher (#7997)

* Fix possible nil pointer dereference in event-dispatcher

* readErr -> err

---------

Co-authored-by: Christoph Stäbler <[email protected]>

Author: knative-prow-robot

pkg/kncloudevents/event_dispatcher.go

@@ -325,11 +325,11 @@ func (d *Dispatcher) executeRequest(ctx context.Context, target duckv1.Addressab
 	dispatchInfo.ResponseHeader = response.Header
 
 	body := new(bytes.Buffer)
-	_, readErr := body.ReadFrom(response.Body)
+	_, err = body.ReadFrom(response.Body)
 
 	if isFailure(response.StatusCode) {
 		// Read response body into dispatchInfo for failures
-		if readErr != nil && readErr != io.EOF {
+		if err != nil && err != io.EOF {
 			dispatchInfo.ResponseBody = []byte(fmt.Sprintf("dispatch resulted in status \"%s\". Could not read response body: error: %s", response.Status, err.Error()))
 		} else {
 			dispatchInfo.ResponseBody = body.Bytes()
@@ -341,7 +341,7 @@ func (d *Dispatcher) executeRequest(ctx context.Context, target duckv1.Addressab
 	}
 
 	var responseMessageBody []byte
-	if readErr != nil && readErr != io.EOF {
+	if err != nil && err != io.EOF {
 		responseMessageBody = []byte(fmt.Sprintf("Failed to read response body: %s", err.Error()))
 	} else {
 		responseMessageBody = body.Bytes()