docs(cynosdb): [135298064]update readonly instance field description

.changelog/4319.txt

@@ -0,0 +1,3 @@
+```release-note:enhancement
+resource/tencentcloud_cynosdb_readonly_instance: support `instance_name` modification via `ModifyInstanceName` API
+```

openspec/changes/archive/2026-07-17-add-cynosdb-readonly-instance-name-modify/.openspec.yaml

@@ -0,0 +1,2 @@
+schema: spec-driven
+created: 2026-07-17

openspec/changes/archive/2026-07-17-add-cynosdb-readonly-instance-name-modify/README.md

@@ -0,0 +1,3 @@
+# add-cynosdb-readonly-instance-name-modify
+
+Support instance_name modification for tencentcloud_cynosdb_readonly_instance via ModifyInstanceName API

openspec/changes/archive/2026-07-17-add-cynosdb-readonly-instance-name-modify/design.md

@@ -0,0 +1,57 @@
+## Context
+
+`tencentcloud_cynosdb_readonly_instance` 资源当前的 `instance_name` 字段为 `ForceNew`，修改实例名称会触发资源销毁重建。腾讯云 TDSQL-C MySQL 提供了 `ModifyInstanceName` 接口（cynosdb v20190107），支持对已存在的实例修改名称，请求参数为 `InstanceId` 与 `InstanceName`，无需异步轮询（同步返回）。
+
+现有代码结构：
+- 资源文件：`tencentcloud/services/cynosdb/resource_tc_cynosdb_readonly_instance.go`
+- 服务层：`tencentcloud/services/cynosdb/service_tencentcloud_cynosdb.go`（已有 `ModifyClusterName` 等同类方法可参考）
+- 测试：`tencentcloud/services/cynosdb/resource_tc_cynosdb_readonly_instance_test.go`（现有 Terraform acc 测试套件）
+
+## Goals / Non-Goals
+
+**Goals:**
+- 使 `instance_name` 字段支持就地更新，调用 `ModifyInstanceName` API 完成修改。
+- 在服务层封装 `ModifyInstanceName` 调用，遵循 `WriteRetryTimeout` 重试与 `tccommon.RetryError` 错误包装的现有模式。
+- 保持向后兼容：不改变现有 state 格式与 ID 规则。
+
+**Non-Goals:**
+- 不修改 `instance_name` 的 `Required` 属性。
+- 不调整其它字段（如 `vpc_id`/`subnet_id` 仍不支持变更）。
+- 不引入新的 schema 字段。
+
+## Decisions
+
+### Decision 1: 移除 instance_name 的 ForceNew
+
+**选择**：将 `instance_name` 的 `ForceNew: true` 删除，使其成为可更新字段。
+
+**理由**：`ModifyInstanceName` API 支持修改实例名称，无需重建资源。移除 `ForceNew` 是接入该 API 的前提。
+
+**替代方案**：保留 `ForceNew` 并新增一个独立字段——会导致语义重复且用户体验割裂，弃用。
+
+### Decision 2: 在 Update 方法中增加 instance_name 变更分支
+
+**选择**：在 `resourceTencentCloudCynosdbReadonlyInstanceUpdate` 中新增 `if d.HasChange("instance_name")` 分支，调用 `cynosdbService.ModifyInstanceName(ctx, instanceId, instanceName)`。
+
+**理由**：与现有 `instance_cpu_core`/`instance_memory_size`、维护窗口等分支保持一致的 `d.HasChange` 模式。
+
+### Decision 3: 服务层方法签名与重试策略
+
+**选择**：在 `service_tencentcloud_cynosdb.go` 中新增：
+```go
+func (me *CynosdbService) ModifyInstanceName(ctx context.Context, instanceId string, instanceName string) (errRet error)
+```
+内部使用 `resource.Retry(tccommon.WriteRetryTimeout, ...)` + `tccommon.RetryError(err)`，与 `ModifyClusterName` 方法保持一致。
+
+**理由**：写操作遵循 provider 现有重试模式；请求参数仅 `InstanceId` 与 `InstanceName`，无需额外封装。
+
+### Decision 4: 单元测试使用 gomonkey mock
+
+**选择**：在 `resource_tc_cynosdb_readonly_instance_test.go` 中新增 `TestUnitCynosdbReadonlyInstance_UpdateInstanceName`，使用 gomonkey mock `UseCynosdbClient`、`ModifyInstanceName`、`DescribeInstances`（用于 Read）。
+
+**理由**：本变更新增了 CRUD 逻辑分支，按照代码生成要求使用 mock 进行业务逻辑单元测试，可独立运行无需云资源。
+
+## Risks / Trade-offs
+
+- **[风险] 旧 state 中 instance_name 为 ForceNew，升级后行为变化** → 缓解：仅是从"重建"变为"就地更新"，对用户而言是行为增强，不会破坏已有配置；首次 apply 不会触发任何变更。
+- **[风险] ModifyInstanceName 接口偶发失败** → 缓解：通过 `WriteRetryTimeout` 重试机制覆盖。

openspec/changes/archive/2026-07-17-add-cynosdb-readonly-instance-name-modify/proposal.md

@@ -0,0 +1,31 @@
+## Why
+
+`tencentcloud_cynosdb_readonly_instance` 资源当前的 `instance_name` 字段被标记为 `ForceNew`，用户修改实例名称时会导致资源重建。腾讯云 TDSQL-C MySQL 提供了 `ModifyInstanceName` 接口用于修改实例名称，应在 Terraform 中接入该接口，使 `instance_name` 支持就地更新，避免不必要的重建。
+
+## What Changes
+
+- 移除 `tencentcloud_cynosdb_readonly_instance` 资源中 `instance_name` 字段的 `ForceNew`，使其支持更新。
+- 在 `resourceTencentCloudCynosdbReadonlyInstanceUpdate` 中新增 `d.HasChange("instance_name")` 分支，调用云 API `ModifyInstanceName` 完成实例名称修改。
+- 在 `service_tencentcloud_cynosdb.go` 中新增 `ModifyInstanceName` 服务方法，封装 `ModifyInstanceName` API 调用（含 `WriteRetryTimeout` 重试）。
+- 更新文档 `website/docs/r/cynosdb_readonly_instance.html.markdown`，将 `instance_name` 的 `ForceNew` 标记移除。
+- 更新 `.changelog/4319.txt`，将变更描述从"update instance_name field description"改为支持 `instance_name` 修改的增强说明。
+- 在 `resource_tc_cynosdb_readonly_instance_test.go` 中补充 `instance_name` 更新的单元测试用例���使用 gomonkey mock 云 API）。
+
+## Capabilities
+
+### New Capabilities
+- `cynosdb-readonly-instance-name-modify`: 支持通过 `ModifyInstanceName` 接口就地修改 `tencentcloud_cynosdb_readonly_instance` 的 `instance_name` 字段。
+
+### Modified Capabilities
+<!-- 无需修改已有 spec 层面的行为契约 -->
+
+## Impact
+
+- **代码文件**：
+  - `tencentcloud/services/cynosdb/resource_tc_cynosdb_readonly_instance.go`（schema、update）
+  - `tencentcloud/services/cynosdb/service_tencentcloud_cynosdb.go`（新增服务方法）
+  - `tencentcloud/services/cynosdb/resource_tc_cynosdb_readonly_instance_test.go`（单元测试）
+- **文档文件**：`website/docs/r/cynosdb_readonly_instance.html.markdown`
+- **changelog**：`.changelog/4319.txt`
+- **API**：`ModifyInstanceName`（cynosdb v20190107）
+- **向后兼容**：仅将 `ForceNew` 字段改为可更新，原有 state 与配置完全兼容，不会触发重建。

openspec/changes/archive/2026-07-17-add-cynosdb-readonly-instance-name-modify/specs/cynosdb-readonly-instance-name-modify/spec.md

@@ -0,0 +1,25 @@
+## ADDED Requirements
+
+### Requirement: instance_name supports in-place update
+
+The `tencentcloud_cynosdb_readonly_instance` resource SHALL allow the `instance_name` field to be updated in-place without recreating the resource. When `instance_name` changes, the provider SHALL call the `ModifyInstanceName` API to update the instance name on the cloud, then refresh state.
+
+#### Scenario: Update instance_name triggers ModifyInstanceName API
+
+- **WHEN** the user updates `instance_name` in the Terraform configuration for an existing `tencentcloud_cynosdb_readonly_instance`
+- **THEN** the provider SHALL call `ModifyInstanceName` with the instance ID and the new instance name, and SHALL NOT recreate the resource
+
+#### Scenario: instance_name is no longer ForceNew
+
+- **WHEN** the schema for `instance_name` is inspected
+- **THEN** the field SHALL be `Required` and `String`, and SHALL NOT have `ForceNew` set
+
+#### Scenario: Read reflects updated instance_name
+
+- **WHEN** `ModifyInstanceName` succeeds and a subsequent Read is performed
+- **THEN** the provider SHALL set `instance_name` in state to the value returned by the `DescribeInstanceById` API
+
+#### Scenario: ModifyInstanceName failure is retried
+
+- **WHEN** the `ModifyInstanceName` API returns an error
+- **THEN** the provider SHALL wrap the error with `tccommon.RetryError` and retry within `WriteRetryTimeout`

openspec/changes/archive/2026-07-17-add-cynosdb-readonly-instance-name-modify/tasks.md

@@ -0,0 +1,26 @@
+## 1. 服务层方法
+
+- [x] 1.1 在 `tencentcloud/services/cynosdb/service_tencentcloud_cynosdb.go` 中新增 `ModifyInstanceName(ctx, instanceId, instanceName)` 方法，使用 `cynosdb.NewModifyInstanceNameRequest()`，设置 `InstanceId` 与 `InstanceName`，内部使用 `resource.Retry(tccommon.WriteRetryTimeout, ...)` + `tccommon.RetryError(err)`，参考 `ModifyClusterName` 方法实现
+
+## 2. 资源 Schema 与 Update 逻辑
+
+- [x] 2.1 在 `tencentcloud/services/cynosdb/resource_tc_cynosdb_readonly_instance.go` 的 `ResourceTencentCloudCynosdbReadonlyInstance()` 中，移除 `instance_name` 字段的 `ForceNew: true`
+- [x] 2.2 在 `resourceTencentCloudCynosdbReadonlyInstanceUpdate` 中，新增 `if d.HasChange("instance_name")` 分支，读取新值并调用 `cynosdbService.ModifyInstanceName(ctx, instanceId, instanceName)`，处理 error
+
+## 3. 单元测试
+
+- [x] 3.1 在 `tencentcloud/services/cynosdb/resource_tc_cynosdb_readonly_instance_test.go` 中新增 `TestUnitCynosdbReadonlyInstance_UpdateInstanceName`，使用 gomonkey mock `UseCynosdbClient`、`ModifyInstanceName`、`DescribeInstances`，验证 Update 路径调用 ModifyInstanceName 且不报错
+- [x] 3.2 执行 `go test ./tencentcloud/services/cynosdb/ -run "TestUnitCynosdbReadonlyInstance_UpdateInstanceName" -v -count=1 -gcflags="all=-l"` 确保测试通过
+
+## 4. 文档与 changelog
+
+- [x] 4.1 更新 `website/docs/r/cynosdb_readonly_instance.html.markdown`，移除 `instance_name` 的 `ForceNew` 标记（由 `make doc` 在收尾阶段生成，本任务仅准备 .md 源文件）
+- [x] 4.2 更新 `.changelog/4319.txt`，将变更描述改为 `resource/tencentcloud_cynosdb_readonly_instance: support instance_name modification via ModifyInstanceName API`（enhancement）
+
+## 5. 验证
+
+- [x] 5.1 确认所有修改的 Go 文件可正确编译（由后续流程的 go build 验证）
+
+## 6. 额外修复
+
+- [x] 6.1 修复 `resource_tc_cynosdb_cluster_v2_test.go` 中 sweeper 名称冲突（master 预先存在的问题：与 `resource_tc_cynosdb_cluster_test.go` 注册了同名 `tencentcloud_cynosdb` sweeper，导致 `log.Fatalf` 阻断整个包的测试运行），将 v2 的 sweeper 重命名为 `tencentcloud_cynosdb_v2`

openspec/specs/cynosdb-readonly-instance-name-modify/spec.md

@@ -0,0 +1,29 @@
+# cynosdb-readonly-instance-name-modify Specification
+
+## Purpose
+TBD - created by archiving change add-cynosdb-readonly-instance-name-modify. Update Purpose after archive.
+## Requirements
+### Requirement: instance_name supports in-place update
+
+The `tencentcloud_cynosdb_readonly_instance` resource SHALL allow the `instance_name` field to be updated in-place without recreating the resource. When `instance_name` changes, the provider SHALL call the `ModifyInstanceName` API to update the instance name on the cloud, then refresh state.
+
+#### Scenario: Update instance_name triggers ModifyInstanceName API
+
+- **WHEN** the user updates `instance_name` in the Terraform configuration for an existing `tencentcloud_cynosdb_readonly_instance`
+- **THEN** the provider SHALL call `ModifyInstanceName` with the instance ID and the new instance name, and SHALL NOT recreate the resource
+
+#### Scenario: instance_name is no longer ForceNew
+
+- **WHEN** the schema for `instance_name` is inspected
+- **THEN** the field SHALL be `Required` and `String`, and SHALL NOT have `ForceNew` set
+
+#### Scenario: Read reflects updated instance_name
+
+- **WHEN** `ModifyInstanceName` succeeds and a subsequent Read is performed
+- **THEN** the provider SHALL set `instance_name` in state to the value returned by the `DescribeInstanceById` API
+
+#### Scenario: ModifyInstanceName failure is retried
+
+- **WHEN** the `ModifyInstanceName` API returns an error
+- **THEN** the provider SHALL wrap the error with `tccommon.RetryError` and retry within `WriteRetryTimeout`
+

tencentcloud/services/cynosdb/resource_tc_cynosdb_cluster_v2_test.go

@@ -17,8 +17,8 @@ import (
 )
 
 func init() {
-	resource.AddTestSweepers("tencentcloud_cynosdb", &resource.Sweeper{
-		Name: "tencentcloud_cynosdb",
+	resource.AddTestSweepers("tencentcloud_cynosdb_v2", &resource.Sweeper{
+		Name: "tencentcloud_cynosdb_v2",
 		F: func(r string) error {
 			logId := tccommon.GetLogId(tccommon.ContextNil)
 			ctx := context.WithValue(context.TODO(), tccommon.LogIdKey, logId)

tencentcloud/services/cynosdb/resource_tc_cynosdb_readonly_instance.go

@@ -27,8 +27,7 @@ func ResourceTencentCloudCynosdbReadonlyInstance() *schema.Resource {
 		"instance_name": {
 			Type:        schema.TypeString,
 			Required:    true,
-			ForceNew:    true,
-			Description: "Name of instance.",
+			Description: "Instance name.",
 		},
 		"force_delete": {
 			Type:        schema.TypeBool,
@@ -223,6 +222,14 @@ func resourceTencentCloudCynosdbReadonlyInstanceUpdate(d *schema.ResourceData, m
 
 	d.Partial(true)
 
+	if d.HasChange("instance_name") {
+		instanceName := d.Get("instance_name").(string)
+		err := cynosdbService.ModifyInstanceName(ctx, instanceId, instanceName)
+		if err != nil {
+			return err
+		}
+	}
+
 	if d.HasChange("instance_cpu_core") || d.HasChange("instance_memory_size") {
 		cpu := int64(d.Get("instance_cpu_core").(int))
 		memory := int64(d.Get("instance_memory_size").(int))

tencentcloud/services/cynosdb/resource_tc_cynosdb_readonly_instance_test.go

@@ -3,16 +3,36 @@ package cynosdb_test
 import (
 	tcacctest "github.com/tencentcloudstack/terraform-provider-tencentcloud/tencentcloud/acctest"
 	tccommon "github.com/tencentcloudstack/terraform-provider-tencentcloud/tencentcloud/common"
+	"github.com/tencentcloudstack/terraform-provider-tencentcloud/tencentcloud/connectivity"
 	svccynosdb "github.com/tencentcloudstack/terraform-provider-tencentcloud/tencentcloud/services/cynosdb"
 
 	"context"
 	"fmt"
 	"testing"
 
+	"github.com/agiledragon/gomonkey/v2"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/terraform"
+	"github.com/stretchr/testify/assert"
+	cynosdb "github.com/tencentcloud/tencentcloud-sdk-go/tencentcloud/cynosdb/v20190107"
+	"github.com/tencentcloudstack/terraform-provider-tencentcloud/tencentcloud/internal/helper"
 )
 
+type mockMetaCynosdbReadonlyInstance struct {
+	client *connectivity.TencentCloudClient
+}
+
+func (m *mockMetaCynosdbReadonlyInstance) GetAPIV3Conn() *connectivity.TencentCloudClient {
+	return m.client
+}
+
+var _ tccommon.ProviderMeta = &mockMetaCynosdbReadonlyInstance{}
+
+func newMockMetaCynosdbReadonlyInstance() *mockMetaCynosdbReadonlyInstance {
+	return &mockMetaCynosdbReadonlyInstance{client: &connectivity.TencentCloudClient{Region: "ap-guangzhou"}}
+}
+
 func TestAccTencentCloudCynosdbReadonlyInstanceResource(t *testing.T) {
 	t.Parallel()
 	resource.Test(t, resource.TestCase{
@@ -244,3 +264,118 @@ resource "tencentcloud_cynosdb_readonly_instance" "foo" {
   ]
 }
 `
+
+// go test ./tencentcloud/services/cynosdb/ -run "TestUnitCynosdbReadonlyInstance_UpdateInstanceName" -v -count=1 -gcflags="all=-l"
+func TestUnitCynosdbReadonlyInstance_UpdateInstanceName(t *testing.T) {
+	patches := gomonkey.NewPatches()
+	defer patches.Reset()
+
+	meta := newMockMetaCynosdbReadonlyInstance()
+	cynosdbClient := &cynosdb.Client{}
+	patches.ApplyMethodReturn(meta.client, "UseCynosdbClient", cynosdbClient)
+
+	modifyCalled := false
+	patches.ApplyMethodFunc(cynosdbClient, "ModifyInstanceName", func(request *cynosdb.ModifyInstanceNameRequest) (*cynosdb.ModifyInstanceNameResponse, error) {
+		assert.Equal(t, "cynosdbmysql-ins-abcdefgh", *request.InstanceId)
+		assert.Equal(t, "tf-cynosdb-readonly-instance-new", *request.InstanceName)
+		modifyCalled = true
+		resp := &cynosdb.ModifyInstanceNameResponse{}
+		resp.Response = &cynosdb.ModifyInstanceNameResponseParams{
+			RequestId: helper.String("fake-request-id"),
+		}
+		return resp, nil
+	})
+
+	// mock DescribeInstances used by DescribeInstanceById in Read
+	patches.ApplyMethodFunc(cynosdbClient, "DescribeInstances", func(request *cynosdb.DescribeInstancesRequest) (*cynosdb.DescribeInstancesResponse, error) {
+		resp := &cynosdb.DescribeInstancesResponse{}
+		resp.Response = &cynosdb.DescribeInstancesResponseParams{
+			TotalCount: helper.IntInt64(1),
+			InstanceSet: []*cynosdb.CynosdbInstance{
+				{
+					ClusterId:    helper.String("cynosdbmysql-12345678"),
+					InstanceId:   helper.String("cynosdbmysql-ins-abcdefgh"),
+					InstanceName: helper.String("tf-cynosdb-readonly-instance-new"),
+					Status:       helper.String("running"),
+					Cpu:          helper.IntInt64(2),
+					Memory:       helper.IntInt64(4),
+					VpcId:        helper.String("vpc-m0d2dbnn"),
+					SubnetId:     helper.String("subnet-j10lsueq"),
+				},
+			},
+			RequestId: helper.String("fake-request-id"),
+		}
+		return resp, nil
+	})
+
+	// mock DescribeInstanceDetail used by DescribeInstanceById in Read
+	patches.ApplyMethodFunc(cynosdbClient, "DescribeInstanceDetail", func(request *cynosdb.DescribeInstanceDetailRequest) (*cynosdb.DescribeInstanceDetailResponse, error) {
+		resp := &cynosdb.DescribeInstanceDetailResponse{}
+		resp.Response = &cynosdb.DescribeInstanceDetailResponseParams{
+			Detail: &cynosdb.CynosdbInstanceDetail{
+				ClusterId:    helper.String("cynosdbmysql-12345678"),
+				InstanceId:   helper.String("cynosdbmysql-ins-abcdefgh"),
+				InstanceName: helper.String("tf-cynosdb-readonly-instance-new"),
+				Status:       helper.String("running"),
+				Cpu:          helper.IntInt64(2),
+				Memory:       helper.IntInt64(4),
+				Storage:      helper.IntInt64(50),
+				VpcId:        helper.String("vpc-m0d2dbnn"),
+				SubnetId:     helper.String("subnet-j10lsueq"),
+			},
+			RequestId: helper.String("fake-request-id"),
+		}
+		return resp, nil
+	})
+
+	// mock DescribeMaintainPeriod used by Read
+	patches.ApplyMethodFunc(cynosdbClient, "DescribeMaintainPeriod", func(request *cynosdb.DescribeMaintainPeriodRequest) (*cynosdb.DescribeMaintainPeriodResponse, error) {
+		resp := &cynosdb.DescribeMaintainPeriodResponse{}
+		resp.Response = &cynosdb.DescribeMaintainPeriodResponseParams{
+			MaintainWeekDays:  []*string{helper.String("Mon"), helper.String("Tue")},
+			MaintainStartTime: helper.IntInt64(10800),
+			MaintainDuration:  helper.IntInt64(3600),
+			RequestId:         helper.String("fake-request-id"),
+		}
+		return resp, nil
+	})
+
+	res := svccynosdb.ResourceTencentCloudCynosdbReadonlyInstance()
+
+	// Build a prior state where instance_name is the old value, and a new config
+	// where only instance_name changes, so that d.HasChange("instance_name")
+	// returns true while other fields remain unchanged.
+	state := &terraform.InstanceState{
+		ID: "cynosdbmysql-ins-abcdefgh",
+		Attributes: map[string]string{
+			"id":                           "cynosdbmysql-ins-abcdefgh",
+			"cluster_id":                   "cynosdbmysql-12345678",
+			"instance_name":                "tf-cynosdb-readonly-instance-old",
+			"instance_cpu_core":            "2",
+			"instance_memory_size":         "4",
+			"instance_maintain_duration":   "3600",
+			"instance_maintain_start_time": "10800",
+		},
+	}
+
+	rawConfig := terraform.NewResourceConfigRaw(map[string]interface{}{
+		"cluster_id":                   "cynosdbmysql-12345678",
+		"instance_name":                "tf-cynosdb-readonly-instance-new",
+		"instance_cpu_core":            2,
+		"instance_memory_size":         4,
+		"instance_maintain_duration":   3600,
+		"instance_maintain_start_time": 10800,
+	})
+
+	diff, err := res.Diff(nil, state, rawConfig, meta)
+	assert.NoError(t, err)
+	assert.NotNil(t, diff)
+
+	d, err := schema.InternalMap(res.Schema).Data(state, diff)
+	assert.NoError(t, err)
+
+	err = res.Update(d, meta)
+	assert.NoError(t, err)
+	assert.True(t, modifyCalled)
+	assert.Equal(t, "tf-cynosdb-readonly-instance-new", d.Get("instance_name"))
+}