Dont panic on hook parsing (#1501)

close #1422

server/forge/gitea/gitea.go

@@ -482,6 +482,11 @@ func (c *Gitea) Hook(ctx context.Context, r *http.Request) (*model.Repo, *model.
 		return nil, nil, err
 	}
 
+	if repo == nil || pipeline == nil {
+		// ignore  hook
+		return nil, nil, nil
+	}
+
 	if pipeline.Event == model.EventPull && len(pipeline.ChangedFiles) == 0 {
 		index, err := strconv.ParseInt(strings.Split(pipeline.Ref, "/")[2], 10, 64)
 		if err != nil {

server/forge/gitea/parse.go

@@ -20,6 +20,8 @@ import (
 	"net/http"
 	"strings"
 
+	"github.com/rs/zerolog/log"
+
 	"github.com/woodpecker-ci/woodpecker/server/model"
 )
 
@@ -41,7 +43,8 @@ const (
 // parseHook parses a Gitea hook from an http.Request request and returns
 // Repo and Pipeline detail. If a hook type is unsupported nil values are returned.
 func parseHook(r *http.Request) (*model.Repo, *model.Pipeline, error) {
-	switch r.Header.Get(hookEvent) {
+	hookType := r.Header.Get(hookEvent)
+	switch hookType {
 	case hookPush:
 		return parsePushHook(r.Body)
 	case hookCreated:
@@ -49,6 +52,7 @@ func parseHook(r *http.Request) (*model.Repo, *model.Pipeline, error) {
 	case hookPullRequest:
 		return parsePullRequestHook(r.Body)
 	}
+	log.Debug().Msgf("unsuported hook type: '%s'", hookType)
 	return nil, nil, nil
 }
 
@@ -104,11 +108,14 @@ func parsePullRequestHook(payload io.Reader) (*model.Repo, *model.Pipeline, erro
 		return nil, nil, err
 	}
 
-	// Don't trigger pipelines for non-code changes, or if PR is not open
+	// Don't trigger pipelines for non-code changes ...
 	if pr.Action != actionOpen && pr.Action != actionSync {
+		log.Debug().Msgf("pull_request action is '%s' and no open or sync", pr.Action)
 		return nil, nil, nil
 	}
+	// ... or if PR is not open
 	if pr.PullRequest.State != stateOpen {
+		log.Debug().Msg("pull_request is closed")
 		return nil, nil, nil
 	}