helper/resource: Changelogs and test for #602

.changes/unreleased/BUG FIXES-20260210-153921.yaml

@@ -0,0 +1,5 @@
+kind: BUG FIXES
+body: 'helper/resource: Test steps in `Config` mode using the `TF_ACC_REFRESH_AFTER_APPLY` compatibility flag will now force post-apply plans to refresh.'
+time: 2026-02-10T15:39:21.121944-05:00
+custom:
+    Issue: "602"

.changes/unreleased/BUG FIXES-20260210-154312.yaml

@@ -0,0 +1,6 @@
+kind: BUG FIXES
+body: 'helper/resource: Test steps in `Config` mode using `Destroy: true` and `Check` functions will now create an additional destroy plan prior to
+     running `terraform apply` to avoid a potential "Saved Plan is Stale" error from Terraform.'
+time: 2026-02-10T15:43:12.029656-05:00
+custom:
+    Issue: "602"

.changes/unreleased/BUG FIXES-20260210-154602.yaml

@@ -0,0 +1,5 @@
+kind: BUG FIXES
+body: 'helper/resource: Test steps in `Config` mode using the `TF_ACC_REFRESH_AFTER_APPLY` compatibility flag will not refresh if `ExpectNonEmptyPlan` is true.'
+time: 2026-02-10T15:46:02.221648-05:00
+custom:
+    Issue: "602"

.github/workflows/ci-go.yml

@@ -26,6 +26,7 @@ jobs:
     name: test (Go ${{ matrix.go-version }} / TF ${{ matrix.terraform }})
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
         go-version: [ '1.25', '1.24' ]
         terraform: ${{ fromJSON(vars.TF_VERSIONS_PROTOCOL_V5) }}

helper/resource/testing_new_config.go

@@ -191,7 +191,7 @@ func testStepNewConfig(ctx context.Context, t testing.T, c TestCase, wd *plugint
 				return wd.CreatePlan(ctx, opts...)
 			})
 			if err != nil {
-				return fmt.Errorf("Error running pre-apply plan: %w", err)
+				return fmt.Errorf("Error running destroy plan after step.Check shimmed state was retrieved: %w", err)
 			}
 		}
 

helper/resource/testing_new_config_test.go

@@ -16,6 +16,7 @@ import (
 	"github.com/hashicorp/terraform-plugin-testing/internal/testing/testsdk/resource"
 	"github.com/hashicorp/terraform-plugin-testing/plancheck"
 	"github.com/hashicorp/terraform-plugin-testing/statecheck"
+	"github.com/hashicorp/terraform-plugin-testing/terraform"
 	"github.com/hashicorp/terraform-plugin-testing/tfversion"
 )
 
@@ -906,3 +907,58 @@ func Test_PostApplyFunc_Called(t *testing.T) {
 		t.Error("expected ConfigStateChecks spy1 to be called at least once")
 	}
 }
+
+// This regression test ensures that the combination of Config, Destroy, and Check never result in
+// a "Saved Plan is Stale" error message, which occurs when the state serial does not match the plan.
+//
+// This can occur when the refresh that is only done to produce the shimmed "Check" state produces a new state serial.
+// Running a fresh plan after refreshing solves that issue, which was introduced in: https://github.com/hashicorp/terraform-plugin-testing/pull/602
+func Test_Destroy_Checks_Avoid_Stale_Plan(t *testing.T) {
+	t.Parallel()
+
+	UnitTest(t, TestCase{
+		TerraformVersionChecks: []tfversion.TerraformVersionCheck{
+			tfversion.SkipBelow(tfversion.Version1_0_0), // ProtoV6ProviderFactories
+		},
+		ProtoV6ProviderFactories: map[string]func() (tfprotov6.ProviderServer, error){
+			"test": providerserver.NewProviderServer(testprovider.Provider{
+				Resources: map[string]testprovider.Resource{
+					"test_resource": {
+						CreateResponse: &resource.CreateResponse{
+							NewState: tftypes.NewValue(
+								tftypes.Object{
+									AttributeTypes: map[string]tftypes.Type{
+										"id": tftypes.String,
+									},
+								},
+								map[string]tftypes.Value{
+									"id": tftypes.NewValue(tftypes.String, "test"),
+								},
+							),
+						},
+						SchemaResponse: &resource.SchemaResponse{
+							Schema: &tfprotov6.Schema{
+								Block: &tfprotov6.SchemaBlock{
+									Attributes: []*tfprotov6.SchemaAttribute{
+										{
+											Name:     "id",
+											Type:     tftypes.String,
+											Computed: true,
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+			}),
+		},
+		Steps: []TestStep{
+			{
+				Config:  `resource "test_resource" "test" {}`,
+				Destroy: true,
+				Check:   func(s *terraform.State) error { return nil },
+			},
+		},
+	})
+}