refactor(gen): harden generator (errors + smoke test)

gen/generate.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	_ "embed"
 	"flag"
+	"fmt"
 	"io"
 	"os"
 	"path/filepath"
@@ -27,34 +28,38 @@ func main() {
 	docs := flag.Bool("docs", false, "generate markdown docs")
 
 	flag.Parse()
-	if *outputDir == "" {
-		panic("output directory is empty")
+
+	if err := run(*outputDir, *docs); err != nil {
+		fmt.Fprintln(os.Stderr, "generate:", err)
+		os.Exit(1)
+	}
+}
+
+func run(outputDir string, docs bool) error {
+	if outputDir == "" {
+		return fmt.Errorf("output directory is empty")
 	}
 
 	// when -docs is set, create a list of all supported markdown events as yaml on stdout
 	// todo(cbrgm): clean this up a little bit
-	if *docs {
-		err := ExecuteMarkdownTemplate("", webhookMarkdownTemplate, params)
-		if err != nil {
-			panic(err)
-		}
-		return
+	if docs {
+		return ExecuteMarkdownTemplate("", webhookMarkdownTemplate, params)
 	}
 
 	imp, err := goGithubImportPath("go.mod")
 	if err != nil {
-		panic(err)
+		return err
 	}
 	params.GoGithubImport = imp
 
-	out := filepath.Join(".", *outputDir)
+	out := filepath.Clean(outputDir)
 	if err := os.MkdirAll(out, os.ModePerm); err != nil {
-		panic("failed to create output directory")
+		return fmt.Errorf("create output dir: %w", err)
 	}
 
 	// create events.go
 	if err := ExecuteWebhookEventTemplate(filepath.Join(out, "events"), params); err != nil {
-		panic(err)
+		return err
 	}
 
 	// create individual files for each webhook event type
@@ -67,9 +72,10 @@ func main() {
 			Webhooks:       []GithubWebhooks{param},
 		})
 		if err != nil {
-			panic(err)
+			return err
 		}
 	}
+	return nil
 }
 
 func ExecuteWebhookEventTemplate(file string, data any) error {

gen/generate_test.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+// run() generates events.go referencing the go.mod-derived import path.
+func TestRunGeneratesEvents(t *testing.T) {
+	orig, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() {
+		if err := os.Chdir(orig); err != nil {
+			t.Fatal(err)
+		}
+	}()
+
+	// run() reads ./go.mod, so execute from the repo root.
+	if err := os.Chdir(".."); err != nil {
+		t.Fatal(err)
+	}
+	dir := t.TempDir()
+	if err := run(dir, false); err != nil {
+		t.Fatalf("run failed: %v", err)
+	}
+	data, err := os.ReadFile(filepath.Join(dir, "events.go"))
+	if err != nil {
+		t.Fatalf("events.go not generated: %v", err)
+	}
+	if !strings.Contains(string(data), "google/go-github/v") {
+		t.Fatal("generated events.go missing go-github import")
+	}
+}