From 4f6fb494cb282ccbb38fe6875d214ed33da9d37d Mon Sep 17 00:00:00 2001
From: Marco Ardizzone <marco@zitadel.com>
Date: Mon, 22 Sep 2025 10:28:57 +0200
Subject: [PATCH] Add UnexpectedQueryTypeError

---
 backend/v3/domain/errors.go      | 16 ++++++++++++
 backend/v3/domain/errors_test.go | 42 ++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)
 create mode 100644 backend/v3/domain/errors_test.go

diff --git a/backend/v3/domain/errors.go b/backend/v3/domain/errors.go
index 3dd9129e3ae..29b9587fe5f 100644
--- a/backend/v3/domain/errors.go
+++ b/backend/v3/domain/errors.go
@@ -57,3 +57,19 @@ func NewOrgNameNotChangedError(errID string) error {
 func (err *OrgNameNotChangedError) Error() string {
 	return fmt.Sprintf("ID=%s Message=organization name has not changed", err.ID)
 }
+
+type UnexpectedQueryTypeError[T any] struct {
+	ID           string
+	assertedType T
+}
+
+func NewUnexpectedQueryTypeError[T any](errID string, assertedType T) error {
+	return &UnexpectedQueryTypeError[T]{
+		ID:           errID,
+		assertedType: assertedType,
+	}
+}
+
+func (u *UnexpectedQueryTypeError[T]) Error() string {
+	return fmt.Sprintf("ID=%s Message=unexpected query type '%T'", u.ID, u.assertedType)
+}
diff --git a/backend/v3/domain/errors_test.go b/backend/v3/domain/errors_test.go
new file mode 100644
index 00000000000..c314576ec90
--- /dev/null
+++ b/backend/v3/domain/errors_test.go
@@ -0,0 +1,42 @@
+package domain
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestUnexpectedQueryTypeError_Error(t *testing.T) {
+	tests := []struct {
+		name     string
+		id       string
+		typeVal  any
+		expected string
+	}{
+		{
+			name:     "string type",
+			id:       "id1",
+			typeVal:  "test",
+			expected: "ID=id1 Message=unexpected query type 'string'",
+		},
+		{
+			name:     "int type",
+			id:       "id2",
+			typeVal:  42,
+			expected: "ID=id2 Message=unexpected query type 'int'",
+		},
+		{
+			name:     "struct type",
+			id:       "id3",
+			typeVal:  struct{}{},
+			expected: "ID=id3 Message=unexpected query type 'struct {}'",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := NewUnexpectedQueryTypeError(tt.id, tt.typeVal)
+			assert.Equal(t, tt.expected, err.Error())
+		})
+	}
+}