fix(pipeline): validate presence of tag on tag events to avoid panic (#529)

Author: ecrupper

action/pipeline/validate.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/go-vela/cli/internal/output"
 	"github.com/go-vela/sdk-go/vela"
+	"github.com/go-vela/types/constants"
 	"github.com/go-vela/types/library"
 
 	"github.com/go-vela/server/compiler"
@@ -69,6 +70,10 @@ func (c *Config) Validate() error {
 				return fmt.Errorf("invalid format for template file: %s (valid format: <name>:<source>)", file)
 			}
 		}
+	case "exec":
+		if strings.EqualFold(c.Event, constants.EventTag) && len(c.Tag) == 0 {
+			return fmt.Errorf("no tag provided for tag event")
+		}
 	}
 
 	return nil

action/pipeline/validate_test.go

@@ -32,6 +32,25 @@ func TestPipeline_Config_Validate(t *testing.T) {
 				Output: "",
 			},
 		},
+		{
+			failure: true,
+			config: &Config{
+				Action: "exec",
+				Org:    "github",
+				Repo:   "octocat",
+				Event:  "tag",
+			},
+		},
+		{
+			failure: false,
+			config: &Config{
+				Action: "exec",
+				Org:    "github",
+				Repo:   "octocat",
+				Event:  "tag",
+				Tag:    "v1.0.0",
+			},
+		},
 		{
 			failure: false,
 			config: &Config{