fix: set defaults during validation to prevent override zero values

adapters/humabunrouter/humabunrouter_test.go

@@ -190,16 +190,16 @@ func BenchmarkRawBunRouter(b *testing.B) {
 
 		// Read and validate params
 		id := r.Param("id")
-		huma.Validate(registry, strSchema, pb, huma.ModeReadFromServer, id, res)
+		huma.ValidateAndSetDefaults(registry, strSchema, pb, huma.ModeReadFromServer, id, res)
 
 		ct := r.Header.Get("Content-Type")
-		huma.Validate(registry, strSchema, pb, huma.ModeReadFromServer, ct, res)
+		huma.ValidateAndSetDefaults(registry, strSchema, pb, huma.ModeReadFromServer, ct, res)
 
 		num, err := strconv.Atoi(r.URL.Query().Get("num"))
 		if err != nil {
 			return err
 		}
-		huma.Validate(registry, numSchema, pb, huma.ModeReadFromServer, num, res)
+		huma.ValidateAndSetDefaults(registry, numSchema, pb, huma.ModeReadFromServer, num, res)
 
 		// Read and validate body
 		defer r.Body.Close()
@@ -213,7 +213,7 @@ func BenchmarkRawBunRouter(b *testing.B) {
 			return err
 		}
 
-		huma.Validate(registry, schema, pb, huma.ModeWriteToServer, tmp, res)
+		huma.ValidateAndSetDefaults(registry, schema, pb, huma.ModeWriteToServer, tmp, res)
 		if len(res.Errors) > 0 {
 			return fmt.Errorf("%v", res.Errors)
 		}

adapters/humachi/humachi_test.go

@@ -187,16 +187,16 @@ func BenchmarkRawChi(b *testing.B) {
 
 		// Read and validate params
 		id := chi.URLParam(r, "id")
-		huma.Validate(registry, strSchema, pb, huma.ModeReadFromServer, id, res)
+		huma.ValidateAndSetDefaults(registry, strSchema, pb, huma.ModeReadFromServer, id, res)
 
 		ct := r.Header.Get("Content-Type")
-		huma.Validate(registry, strSchema, pb, huma.ModeReadFromServer, ct, res)
+		huma.ValidateAndSetDefaults(registry, strSchema, pb, huma.ModeReadFromServer, ct, res)
 
 		num, err := strconv.Atoi(r.URL.Query().Get("num"))
 		if err != nil {
 			panic(err)
 		}
-		huma.Validate(registry, numSchema, pb, huma.ModeReadFromServer, num, res)
+		huma.ValidateAndSetDefaults(registry, numSchema, pb, huma.ModeReadFromServer, num, res)
 
 		// Read and validate body
 		defer r.Body.Close()
@@ -210,7 +210,7 @@ func BenchmarkRawChi(b *testing.B) {
 			panic(err)
 		}
 
-		huma.Validate(registry, schema, pb, huma.ModeWriteToServer, tmp, res)
+		huma.ValidateAndSetDefaults(registry, schema, pb, huma.ModeWriteToServer, tmp, res)
 		if len(res.Errors) > 0 {
 			panic(res.Errors)
 		}

adapters/humaecho/humaecho_test.go

@@ -109,16 +109,16 @@ func BenchmarkRawEcho(b *testing.B) {
 
 		// Read and validate params
 		id := c.Param("id")
-		huma.Validate(registry, strSchema, pb, huma.ModeReadFromServer, id, res)
+		huma.ValidateAndSetDefaults(registry, strSchema, pb, huma.ModeReadFromServer, id, res)
 
 		ct := r.Header.Get("Content-Type")
-		huma.Validate(registry, strSchema, pb, huma.ModeReadFromServer, ct, res)
+		huma.ValidateAndSetDefaults(registry, strSchema, pb, huma.ModeReadFromServer, ct, res)
 
 		num, err := strconv.Atoi(c.QueryParam("num"))
 		if err != nil {
 			panic(err)
 		}
-		huma.Validate(registry, numSchema, pb, huma.ModeReadFromServer, num, res)
+		huma.ValidateAndSetDefaults(registry, numSchema, pb, huma.ModeReadFromServer, num, res)
 
 		// Read and validate body
 		defer r.Body.Close()
@@ -132,7 +132,7 @@ func BenchmarkRawEcho(b *testing.B) {
 			panic(err)
 		}
 
-		huma.Validate(registry, schema, pb, huma.ModeWriteToServer, tmp, res)
+		huma.ValidateAndSetDefaults(registry, schema, pb, huma.ModeWriteToServer, tmp, res)
 		if len(res.Errors) > 0 {
 			panic(res.Errors)
 		}

adapters/humago/humago_test.go

@@ -109,16 +109,16 @@ func BenchmarkRawGo(b *testing.B) {
 		if pv, ok := v.(interface{ PathValue(string) string }); ok {
 			id = pv.PathValue("id")
 		}
-		huma.Validate(registry, strSchema, pb, huma.ModeReadFromServer, id, res)
+		huma.ValidateAndSetDefaults(registry, strSchema, pb, huma.ModeReadFromServer, id, res)
 
 		ct := r.Header.Get("Content-Type")
-		huma.Validate(registry, strSchema, pb, huma.ModeReadFromServer, ct, res)
+		huma.ValidateAndSetDefaults(registry, strSchema, pb, huma.ModeReadFromServer, ct, res)
 
 		num, err := strconv.Atoi(r.URL.Query().Get("num"))
 		if err != nil {
 			panic(err)
 		}
-		huma.Validate(registry, numSchema, pb, huma.ModeReadFromServer, num, res)
+		huma.ValidateAndSetDefaults(registry, numSchema, pb, huma.ModeReadFromServer, num, res)
 
 		// Read and validate body
 		defer r.Body.Close()
@@ -132,7 +132,7 @@ func BenchmarkRawGo(b *testing.B) {
 			panic(err)
 		}
 
-		huma.Validate(registry, schema, pb, huma.ModeWriteToServer, tmp, res)
+		huma.ValidateAndSetDefaults(registry, schema, pb, huma.ModeWriteToServer, tmp, res)
 		if len(res.Errors) > 0 {
 			panic(res.Errors)
 		}

huma.go

@@ -1168,7 +1168,7 @@ func Register[I, O any](api API, op Operation, handler func(context.Context, *I)
 				}
 
 				if !op.SkipValidateParams {
-					Validate(oapi.Components.Schemas, p.Schema, pb, ModeWriteToServer, pv, res)
+					ValidateAndSetDefaults(oapi.Components.Schemas, p.Schema, pb, ModeWriteToServer, pv, res)
 				}
 			}
 		})
@@ -1276,7 +1276,19 @@ func Register[I, O any](api API, op Operation, handler func(context.Context, *I)
 							pb.Reset()
 							pb.Push("body")
 							count := len(res.Errors)
-							Validate(oapi.Components.Schemas, inSchema, pb, ModeWriteToServer, parsed, res)
+							ValidateAndSetDefaults(oapi.Components.Schemas, inSchema, pb, ModeWriteToServer, parsed, res)
+
+							// Validate changes the original parsed input setting default values when needed
+							// so we need to marshal the parsed input back to a byte buffer to get the
+							// default values set by the validator.
+							parsedBuff := new(strings.Builder)
+							err := DefaultJSONFormat.Marshal(parsedBuff, parsed)
+							if err != nil {
+								WriteErr(api, ctx, http.StatusBadRequest, "could not set default value", err)
+								return
+							}
+							body = []byte(parsedBuff.String())
+
 							parseErrCount = len(res.Errors) - count
 							if parseErrCount > 0 {
 								errStatus = http.StatusUnprocessableEntity
@@ -1307,7 +1319,7 @@ func Register[I, O any](api API, op Operation, handler func(context.Context, *I)
 							// Set defaults for any fields that were not in the input.
 							defaults.Every(v, func(item reflect.Value, def any) {
 								if item.IsZero() {
-									item.Set(reflect.Indirect(reflect.ValueOf(def)))
+									// item.Set(reflect.Indirect(reflect.ValueOf(def)))
 								}
 							})
 						}

huma_test.go

@@ -642,6 +642,41 @@ func TestFeatures(t *testing.T) {
 			URL:    "/body",
 			Body:   `{"items": [{"id": 1}]}`,
 		},
+		{
+			Name: "request-body-defaults-respect-input",
+			Register: func(t *testing.T, api huma.API) {
+				huma.Register(api, huma.Operation{
+					Method: http.MethodPut,
+					Path:   "/body",
+				}, func(ctx context.Context, input *struct {
+					Body struct {
+						// Test defaults for primitive types.
+						Name  string `json:"name,omitempty" default:"Huma"`
+						Count int    `json:"count,omitempty" default:"5"`
+						// Test defaults for slices of primitives.
+						Tags    []string `json:"tags,omitempty" default:"foo, bar"`
+						Numbers []int    `json:"numbers,omitempty" default:"[1, 2, 3]"`
+						// Test defaults for fields within slices of structs.
+						Items []struct {
+							ID       int  `json:"id"`
+							Verified bool `json:"verified,omitempty" default:"true"`
+						} `json:"items,omitempty"`
+					}
+				},
+				) (*struct{}, error) {
+					assert.Equal(t, "Huma", input.Body.Name)
+					assert.Equal(t, 5, input.Body.Count)
+					assert.Equal(t, []string{"foo", "bar"}, input.Body.Tags)
+					assert.Equal(t, []int{1, 2, 3}, input.Body.Numbers)
+					assert.Equal(t, 1, input.Body.Items[0].ID)
+					assert.False(t, input.Body.Items[0].Verified)
+					return nil, nil
+				})
+			},
+			Method: http.MethodPut,
+			URL:    "/body",
+			Body:   `{"items": [{"id": 1, "verified": false}]}`,
+		},
 		{
 			Name: "request-body-required",
 			Register: func(t *testing.T, api huma.API) {

schema_test.go

@@ -1184,7 +1184,7 @@ func TestSchemaOld(t *testing.T) {
 	s2 := r.Schema(reflect.TypeOf(TestInput{}), false, "")
 	pb := huma.NewPathBuffer(make([]byte, 0, 128), 0)
 	res := huma.ValidateResult{}
-	huma.Validate(r, s2, pb, huma.ModeReadFromServer, map[string]any{
+	huma.ValidateAndSetDefaults(r, s2, pb, huma.ModeReadFromServer, map[string]any{
 		"name": "foo",
 		"sub": map[string]any{
 			"num": 1.0,
@@ -1412,15 +1412,15 @@ func BenchmarkSchema(b *testing.B) {
 	}
 	pb := huma.NewPathBuffer(make([]byte, 0, 128), 0)
 	res := huma.ValidateResult{}
-	huma.Validate(r, s2, pb, huma.ModeReadFromServer, input, &res)
+	huma.ValidateAndSetDefaults(r, s2, pb, huma.ModeReadFromServer, input, &res)
 	assert.Empty(b, res.Errors)
 
 	b.ResetTimer()
 	b.ReportAllocs()
 	for i := 0; i < b.N; i++ {
 		pb.Reset()
 		res.Reset()
-		huma.Validate(r, s2, pb, huma.ModeReadFromServer, input, &res)
+		huma.ValidateAndSetDefaults(r, s2, pb, huma.ModeReadFromServer, input, &res)
 		if len(res.Errors) > 0 {
 			b.Fatal(res.Errors)
 		}
@@ -1446,15 +1446,15 @@ func BenchmarkSchemaErrors(b *testing.B) {
 	}
 	pb := huma.NewPathBuffer(make([]byte, 0, 128), 0)
 	res := huma.ValidateResult{}
-	huma.Validate(r, s2, pb, huma.ModeReadFromServer, input, &res)
+	huma.ValidateAndSetDefaults(r, s2, pb, huma.ModeReadFromServer, input, &res)
 	assert.NotEmpty(b, res.Errors)
 
 	b.ResetTimer()
 	b.ReportAllocs()
 	for i := 0; i < b.N; i++ {
 		pb.Reset()
 		res.Reset()
-		huma.Validate(r, s2, pb, huma.ModeReadFromServer, input, &res)
+		huma.ValidateAndSetDefaults(r, s2, pb, huma.ModeReadFromServer, input, &res)
 		if len(res.Errors) == 0 {
 			b.Fatal("expected error")
 		}

validate.go

@@ -272,7 +272,7 @@ func validateOneOf(r Registry, s *Schema, path *PathBuffer, mode ValidateMode, v
 	found := false
 	subRes := &ValidateResult{}
 	for _, sub := range s.OneOf {
-		Validate(r, sub, path, mode, v, subRes)
+		ValidateAndSetDefaults(r, sub, path, mode, v, subRes)
 		if len(subRes.Errors) == 0 {
 			if found {
 				res.Add(path, v, "expected value to match exactly one schema but matched multiple")
@@ -290,7 +290,7 @@ func validateAnyOf(r Registry, s *Schema, path *PathBuffer, mode ValidateMode, v
 	matches := 0
 	subRes := &ValidateResult{}
 	for _, sub := range s.AnyOf {
-		Validate(r, sub, path, mode, v, subRes)
+		ValidateAndSetDefaults(r, sub, path, mode, v, subRes)
 		if len(subRes.Errors) == 0 {
 			matches++
 		}
@@ -338,11 +338,12 @@ func validateDiscriminator(r Registry, s *Schema, path *PathBuffer, mode Validat
 		return
 	}
 
-	Validate(r, r.SchemaFromRef(ref), path, mode, v, res)
+	ValidateAndSetDefaults(r, r.SchemaFromRef(ref), path, mode, v, res)
 }
 
 // Validate an input value against a schema, collecting errors in the validation
-// result object. If successful, `res.Errors` will be empty. It is suggested
+// result object. And set default values on omitted fields
+// If validation is successful, `res.Errors` will be empty. It is suggested
 // to use a `sync.Pool` to reuse the PathBuffer and ValidateResult objects,
 // making sure to call `Reset()` on them before returning them to the pool.
 //
@@ -353,11 +354,11 @@ func validateDiscriminator(r Registry, s *Schema, path *PathBuffer, mode Validat
 //
 //	var value any
 //	json.Unmarshal([]byte(`{"foo": "bar"}`), &v)
-//	huma.Validate(registry, schema, pb, huma.ModeWriteToServer, value, res)
+//	huma.ValidateAndSetDefaults(registry, schema, pb, huma.ModeWriteToServer, value, res)
 //	for _, err := range res.Errors {
 //		fmt.Println(err.Error())
 //	}
-func Validate(r Registry, s *Schema, path *PathBuffer, mode ValidateMode, v any, res *ValidateResult) {
+func ValidateAndSetDefaults(r Registry, s *Schema, path *PathBuffer, mode ValidateMode, v any, res *ValidateResult) {
 	// Get the actual schema if this is a reference.
 	for s.Ref != "" {
 		s = r.SchemaFromRef(s.Ref)
@@ -377,13 +378,13 @@ func Validate(r Registry, s *Schema, path *PathBuffer, mode ValidateMode, v any,
 
 	if s.AllOf != nil {
 		for _, sub := range s.AllOf {
-			Validate(r, sub, path, mode, v, res)
+			ValidateAndSetDefaults(r, sub, path, mode, v, res)
 		}
 	}
 
 	if s.Not != nil {
 		subRes := &ValidateResult{}
-		Validate(r, s.Not, path, mode, v, subRes)
+		ValidateAndSetDefaults(r, s.Not, path, mode, v, subRes)
 		if len(subRes.Errors) == 0 {
 			res.Add(path, v, validation.MsgExpectedNotMatchSchema)
 		}
@@ -576,7 +577,7 @@ func handleArray[T any](r Registry, s *Schema, path *PathBuffer, mode ValidateMo
 
 	for i, item := range arr {
 		path.PushIndex(i)
-		Validate(r, s.Items, path, mode, item, res)
+		ValidateAndSetDefaults(r, s.Items, path, mode, item, res)
 		path.Pop()
 	}
 }
@@ -602,6 +603,11 @@ func handleMapString(r Registry, s *Schema, path *PathBuffer, mode ValidateMode,
 		// the `for` loop never runs.
 		readOnly := v.ReadOnly
 		writeOnly := v.WriteOnly
+
+		if m[k] == nil && v.Default != nil {
+			m[k] = v.Default
+		}
+
 		for v.Ref != "" {
 			v = r.SchemaFromRef(v.Ref)
 		}
@@ -659,7 +665,7 @@ func handleMapString(r Registry, s *Schema, path *PathBuffer, mode ValidateMode,
 		}
 
 		path.Push(k)
-		Validate(r, v, path, mode, m[actualKey], res)
+		ValidateAndSetDefaults(r, v, path, mode, m[k], res)
 		path.Pop()
 	}
 
@@ -692,7 +698,7 @@ func handleMapString(r Registry, s *Schema, path *PathBuffer, mode ValidateMode,
 			}
 
 			path.Push(k)
-			Validate(r, addl, path, mode, v, res)
+			ValidateAndSetDefaults(r, addl, path, mode, v, res)
 			path.Pop()
 		}
 	}
@@ -719,6 +725,11 @@ func handleMapAny(r Registry, s *Schema, path *PathBuffer, mode ValidateMode, m
 		// the `for` loop never runs.
 		readOnly := v.ReadOnly
 		writeOnly := v.WriteOnly
+
+		if m[k] == nil && v.Default != nil {
+			m[k] = v.Default
+		}
+
 		for v.Ref != "" {
 			v = r.SchemaFromRef(v.Ref)
 		}
@@ -763,7 +774,7 @@ func handleMapAny(r Registry, s *Schema, path *PathBuffer, mode ValidateMode, m
 		}
 
 		path.Push(k)
-		Validate(r, v, path, mode, m[k], res)
+		ValidateAndSetDefaults(r, v, path, mode, m[k], res)
 		path.Pop()
 	}
 
@@ -794,7 +805,7 @@ func handleMapAny(r Registry, s *Schema, path *PathBuffer, mode ValidateMode, m
 				kStr = fmt.Sprint(k)
 			}
 			path.Push(kStr)
-			Validate(r, addl, path, mode, v, res)
+			ValidateAndSetDefaults(r, addl, path, mode, v, res)
 			path.Pop()
 		}
 	}
@@ -858,7 +869,7 @@ func (v *ModelValidator) Validate(typ reflect.Type, value any) []error {
 
 	s := v.registry.Schema(typ, true, typ.Name())
 
-	Validate(v.registry, s, v.pb, ModeReadFromServer, value, v.result)
+	ValidateAndSetDefaults(v.registry, s, v.pb, ModeReadFromServer, value, v.result)
 
 	if len(v.result.Errors) > 0 {
 		return v.result.Errors