internal: add structdiff.IsEqual() (#4203)

## Changes
New function structdiff.IsEqual() which follows the same logic as
structdiff.GetStructDiff() but does not build a diff.

## Why
Need this in #4201

reflect.DeepEqual() does not work for types with ForceSendFields because
ForceSendFields can have more or less fields in it without changing the
actual value.

## Tests
Unit tests.

Author: denik

libs/structs/structdiff/diff_test.go

@@ -434,6 +434,12 @@ func TestGetStructDiff(t *testing.T) {
 			assert.NoError(t, err)
 			assert.Nil(t, got)
 		})
+
+		t.Run(tt.name+" IsEqual", func(t *testing.T) {
+			equal := IsEqual(tt.a, tt.b)
+			expected := len(tt.want) == 0 && !tt.wantErr
+			assert.Equal(t, expected, equal)
+		})
 	}
 }
 

libs/structs/structdiff/equal.go

@@ -0,0 +1,161 @@
+package structdiff
+
+import (
+	"reflect"
+	"slices"
+
+	"github.com/databricks/cli/libs/structs/structtag"
+)
+
+// IsEqual compares two Go structs and returns true if they are equal.
+// It uses the same comparison logic as GetStructDiff but is more efficient
+// as it short-circuits on the first difference found.
+// Respects ForceSendFields if present.
+// Types of a and b must match exactly, otherwise returns false.
+// Note, reflect.DeepEqual() does not work for SDK structs, because ForceSendFields can contain different sets for the same value.
+func IsEqual(a, b any) bool {
+	v1 := reflect.ValueOf(a)
+	v2 := reflect.ValueOf(b)
+
+	if !v1.IsValid() && !v2.IsValid() {
+		return true
+	}
+
+	if !v1.IsValid() || !v2.IsValid() {
+		return false
+	}
+
+	if v1.Type() != v2.Type() {
+		return false
+	}
+
+	return equalValues(v1, v2)
+}
+
+// equalValues returns true if v1 and v2 are equal.
+func equalValues(v1, v2 reflect.Value) bool {
+	if !v1.IsValid() {
+		return !v2.IsValid()
+	} else if !v2.IsValid() {
+		return false
+	}
+
+	v1Type := v1.Type()
+
+	if v1Type != v2.Type() {
+		return false
+	}
+
+	kind := v1.Kind()
+
+	// Perform nil checks for nilable types.
+	switch kind {
+	case reflect.Pointer, reflect.Map, reflect.Slice, reflect.Interface, reflect.Chan, reflect.Func:
+		v1Nil := v1.IsNil()
+		v2Nil := v2.IsNil()
+		if v1Nil && v2Nil {
+			return true
+		}
+		if v1Nil || v2Nil {
+			return false
+		}
+	default:
+		// Not a nilable type.
+		// Proceed with direct comparison below.
+	}
+
+	switch kind {
+	case reflect.Pointer:
+		return equalValues(v1.Elem(), v2.Elem())
+	case reflect.Struct:
+		return equalStruct(v1, v2)
+	case reflect.Slice, reflect.Array:
+		if v1.Len() != v2.Len() {
+			return false
+		}
+		for i := range v1.Len() {
+			if !equalValues(v1.Index(i), v2.Index(i)) {
+				return false
+			}
+		}
+	case reflect.Map:
+		if v1Type.Key().Kind() == reflect.String {
+			return equalMapStringKey(v1, v2)
+		}
+		return reflect.DeepEqual(v1.Interface(), v2.Interface())
+	default:
+		return reflect.DeepEqual(v1.Interface(), v2.Interface())
+	}
+	return true
+}
+
+func equalStruct(s1, s2 reflect.Value) bool {
+	t := s1.Type()
+	forced1 := getForceSendFields(s1)
+	forced2 := getForceSendFields(s2)
+
+	for i := range t.NumField() {
+		sf := t.Field(i)
+		if !sf.IsExported() || sf.Name == "ForceSendFields" {
+			continue
+		}
+
+		// Continue traversing embedded structs.
+		if sf.Anonymous {
+			if !equalValues(s1.Field(i), s2.Field(i)) {
+				return false
+			}
+			continue
+		}
+
+		jsonTag := structtag.JSONTag(sf.Tag.Get("json"))
+
+		v1Field := s1.Field(i)
+		v2Field := s2.Field(i)
+
+		zero1 := v1Field.IsZero()
+		zero2 := v2Field.IsZero()
+
+		if zero1 || zero2 {
+			if jsonTag.OmitEmpty() {
+				if zero1 {
+					if !slices.Contains(forced1, sf.Name) {
+						v1Field = reflect.ValueOf(nil)
+					}
+				}
+				if zero2 {
+					if !slices.Contains(forced2, sf.Name) {
+						v2Field = reflect.ValueOf(nil)
+					}
+				}
+			}
+		}
+
+		if !equalValues(v1Field, v2Field) {
+			return false
+		}
+	}
+	return true
+}
+
+func equalMapStringKey(m1, m2 reflect.Value) bool {
+	keySet := map[string]reflect.Value{}
+	for _, k := range m1.MapKeys() {
+		// Key is always string at this point
+		ks := k.Interface().(string)
+		keySet[ks] = k
+	}
+	for _, k := range m2.MapKeys() {
+		ks := k.Interface().(string)
+		keySet[ks] = k
+	}
+
+	for _, k := range keySet {
+		v1 := m1.MapIndex(k)
+		v2 := m2.MapIndex(k)
+		if !equalValues(v1, v2) {
+			return false
+		}
+	}
+	return true
+}