fix 5720: the formValue should read the first value

server/web/context/form.go

@@ -170,20 +170,9 @@ func formTagName(fieldT reflect.StructField) (string, bool) {
 
 func formValue(tag string, form url.Values, fieldT reflect.StructField) (string, bool) {
 	formValues := form[tag]
-	var value string
 	if len(formValues) == 0 {
 		defaultValue := fieldT.Tag.Get("default")
-		if defaultValue != "" {
-			value = defaultValue
-		} else {
-			return "", false
+		return defaultValue, defaultValue != ""
 	}
-	}
-	if len(formValues) == 1 {
-		value = formValues[0]
-		if value == "" {
-			return "", false
-		}
-	}
-	return value, true
+	return formValues[0], true
 }

server/web/context/form_test.go

@@ -0,0 +1,88 @@
+// Copyright 2024 beego
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package context
+
+import (
+	"net/url"
+	"reflect"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFormValue(t *testing.T) {
+	typ := reflect.TypeOf(TestStruct{})
+	defField, _ := typ.FieldByName("DefaultField")
+	noDefField, _ := typ.FieldByName("NoDefaultField")
+	testCases := []struct {
+		name string
+		tag  string
+
+		form  url.Values
+		field reflect.StructField
+
+		wantRes string
+		wantOk  bool
+	}{
+		{
+			name:  "use value",
+			tag:   "defaultField",
+			field: defField,
+			form: map[string][]string{
+				"defaultField": {"abc", "bcd"},
+			},
+			wantRes: "abc",
+			wantOk:  true,
+		},
+		{
+			name:  "empty value",
+			tag:   "defaultField",
+			field: defField,
+			form: map[string][]string{
+				"defaultField": {"", "bcd"},
+			},
+			wantRes: "",
+			wantOk:  true,
+		},
+		{
+			name:    "use default value",
+			tag:     "defaultField",
+			field:   defField,
+			form:    map[string][]string{},
+			wantRes: "Tom",
+			wantOk:  true,
+		},
+		{
+			name:   "no value",
+			tag:    "no",
+			field:  noDefField,
+			form:   map[string][]string{},
+			wantOk: false,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			val, ok := formValue(tc.tag, tc.form, tc.field)
+			assert.Equal(t, tc.wantRes, val)
+			assert.Equal(t, tc.wantOk, ok)
+		})
+	}
+}
+
+type TestStruct struct {
+	DefaultField   string `form:"defaultField" default:"Tom"`
+	NoDefaultField string `form:"noDefaultField"`
+}