fix: set metadata when not provided (#1189)

compiler/native/compile.go

@@ -17,6 +17,7 @@ import (
 	yml "gopkg.in/yaml.v3"
 
 	api "github.com/go-vela/server/api/types"
+	"github.com/go-vela/server/internal"
 	"github.com/go-vela/types/constants"
 	"github.com/go-vela/types/library"
 	"github.com/go-vela/types/pipeline"
@@ -61,6 +62,11 @@ func (c *client) Compile(ctx context.Context, v interface{}) (*pipeline.Build, *
 		event = event + ":" + action
 	}
 
+	// populate metadata when not provided using compiler.WithMetadata
+	if c.metadata == nil {
+		c.metadata = &internal.Metadata{Database: &internal.Database{}, Queue: &internal.Queue{}, Source: &internal.Source{}, Vela: &internal.Vela{}}
+	}
+
 	// create the ruledata to purge steps
 	r := &pipeline.RuleData{
 		Branch:   c.build.GetBranch(),