add detailed debug log

plugin/plugin.go

@@ -92,6 +92,15 @@ func (p *Plugin) Find(ctx context.Context, droneRequest *config.Request) (*drone
 
 // getConfig retrieves drone config data from the repo
 func (p *Plugin) getConfig(ctx context.Context, req *request) (string, error) {
+	logrus.WithFields(logrus.Fields{
+		"after":   req.Build.After,
+		"before":  req.Build.Before,
+		"branch":  req.Repo.Branch,
+		"ref":     req.Build.Ref,
+		"slug":    req.Repo.Slug,
+		"trigger": req.Build.Trigger,
+	}).Debugf("drone-tree-config environment")
+
 	// get changed files
 	changedFiles, err := p.getScmChanges(ctx, req)
 	if err != nil {

plugin/scm.go

@@ -51,16 +51,9 @@ func (p *Plugin) getScmChanges(ctx context.Context, req *request) ([]string, err
 		}
 	} else {
 		// use diff to get changed files
-		repoBranch := req.Repo.Branch
-		commitBranch := req.Build.Source
 		before := req.Build.Before
 		after := req.Build.After
 
-		// check for branch pr
-		if commitBranch != repoBranch {
-			before = repoBranch
-		}
-
 		// check for broken before
 		if before == "0000000000000000000000000000000000000000" || before == "" {
 			before = fmt.Sprintf("%s~1", after)