[breaking] allow handlers to return errors

Author: lispyclouds

README.md

@@ -12,7 +12,7 @@ What if you can influence the CLI behaviour from the server? This enables you to
 
 ### Status
 
-Alpha, stabilising API and looking for design/usage feedback!
+Alpha, looking for design/usage feedback!
 
 ### Ideally support:
 - more of the OpenAPI types and their checks. eg arrays, enums, objects, multi types etc
@@ -56,17 +56,19 @@ Define a cobra root command:
 
 ```go
 rootCmd := &cobra.Command{
-    Use:   "calc",
-    Short: "My Calc",
-    Long:  "My Calc powered by OpenAPI",
+	Use:   "calc",
+	Short: "My Calc",
+	Long:  "My Calc powered by OpenAPI",
 }
 ```
 
 Define one or more handler functions of the following signature:
 ```go
-func handler(opts *cobra.Command, args []string, data climate.HandlerData) {
-    // do something more useful
-    slog.Info("called!", "data", fmt.Sprintf("%+v", data))
+func handler(opts *cobra.Command, args []string, data climate.HandlerData) error {
+	slog.Info("called!", "data", fmt.Sprintf("%+v", data))
+	err := doSomethingUseful(data)
+
+	return err
 }
 ```
 #### Handler Data
@@ -89,10 +91,10 @@ Define the handlers for the necessary operations. These map to the `operationId`
 
 ```go
 handlers := map[string]Handler{
-    "AddGet":      handler,
-    "AddPost":     handler,
-    "HealthCheck": handler,
-    "GetInfo":     handler,
+	"AddGet":      handler,
+	"AddPost":     handler,
+	"HealthCheck": handler,
+	"GetInfo":     handler,
 }
 ```
 

lib.go

@@ -42,7 +42,7 @@ type HandlerData struct {
 }
 
 // The handler signature
-type Handler func(opts *cobra.Command, args []string, data HandlerData)
+type Handler func(opts *cobra.Command, args []string, data HandlerData) error
 
 type extensions struct {
 	hidden  bool
@@ -260,12 +260,12 @@ func BootstrapV3(rootCmd *cobra.Command, model libopenapi.DocumentModel[v3.Docum
 			if op.Summary != "" {
 				cmd.Short = op.Summary
 			}
-			cmd.Run = func(opts *cobra.Command, args []string) {
+			cmd.RunE = func(opts *cobra.Command, args []string) error {
 				if err := interpolatePath(&cmd, &hData); err != nil {
-					slog.Error("Error interpolating path", "err", err)
+					return err
 				}
 
-				handler(opts, args, hData)
+				return handler(opts, args, hData)
 			}
 
 			cmd.Use = op.OperationId // default

lib_test.go

@@ -77,12 +77,14 @@ func TestBootstrapV3(t *testing.T) {
 	model, err := LoadFileV3("api.yaml")
 	assert.NoError(t, err)
 
-	handler := func(opts *cobra.Command, args []string, data HandlerData) {
+	handler := func(opts *cobra.Command, args []string, data HandlerData) error {
 		assert.Equal(t, data.PathParams, []ParamMeta{{Name: "p1", Type: Integer}})
 		assert.Equal(t, data.QueryParams, []ParamMeta{{Name: "p2", Type: String}})
 		assert.Equal(t, data.HeaderParams, []ParamMeta{{Name: "p3", Type: Number}})
 		assert.Equal(t, data.CookieParams, []ParamMeta{{Name: "p4", Type: Boolean}})
 		assert.Equal(t, data.RequestBodyParam, &ParamMeta{Name: "req-body", Type: String})
+
+		return nil
 	}
 	rootCmd := &cobra.Command{
 		Use:   "calc",