From d1ea20ac1ae305679fb6654d868a0dfce7e801dd Mon Sep 17 00:00:00 2001
From: Radek Simko <radek.simko@gmail.com>
Date: Thu, 30 Apr 2026 12:30:14 +0100
Subject: [PATCH] command/output: Add regression test

Co-authored-by: Daniel Schmidt <danielmschmidt92@gmail.com>
---
 internal/command/output_test.go               | 82 +++++++++++++++++++
 .../.terraform/terraform.tfstate              | 12 +++
 .../output-backend-with-deprecation/main.tf   |  7 ++
 3 files changed, 101 insertions(+)
 create mode 100644 internal/command/testdata/output-backend-with-deprecation/.terraform/terraform.tfstate
 create mode 100644 internal/command/testdata/output-backend-with-deprecation/main.tf

diff --git a/internal/command/output_test.go b/internal/command/output_test.go
index 5cff3f4e6f..3b0666bbd8 100644
--- a/internal/command/output_test.go
+++ b/internal/command/output_test.go
@@ -13,9 +13,13 @@ import (
 	"github.com/zclconf/go-cty/cty"
 
 	"github.com/hashicorp/terraform/internal/addrs"
+	"github.com/hashicorp/terraform/internal/backend"
+	backendInit "github.com/hashicorp/terraform/internal/backend/init"
+	"github.com/hashicorp/terraform/internal/backend/remote-state/inmem"
 	"github.com/hashicorp/terraform/internal/providers"
 	"github.com/hashicorp/terraform/internal/states"
 	"github.com/hashicorp/terraform/internal/states/statefile"
+	"github.com/hashicorp/terraform/internal/tfdiags"
 )
 
 func TestOutput(t *testing.T) {
@@ -381,3 +385,81 @@ func TestOutput_stateDefault(t *testing.T) {
 		t.Fatalf("bad: %#v", actual)
 	}
 }
+
+// deprecatedInmemBackend wraps the inmem backend and injects a deprecation
+// warning from PrepareConfig, simulating a backend with deprecated attributes
+// (like the S3 backend's dynamodb_table).
+type deprecatedInmemBackend struct {
+	backend.Backend
+}
+
+func (b *deprecatedInmemBackend) PrepareConfig(obj cty.Value) (cty.Value, tfdiags.Diagnostics) {
+	newObj, diags := b.Backend.PrepareConfig(obj)
+	diags = diags.Append(tfdiags.SimpleWarning(`The attribute "deprecated_attr" is deprecated.`))
+	return newObj, diags
+}
+
+func TestOutputRaw_warningsSuppressed(t *testing.T) {
+	// Pre-populate the inmem backend with a state containing an output value
+	inmem.Reset()
+	originalState := states.BuildState(func(s *states.SyncState) {
+		s.SetOutputValue(
+			addrs.OutputValue{Name: "foo"}.Absolute(addrs.RootModuleInstance),
+			cty.StringVal("bar"),
+			false,
+		)
+	})
+
+	// Register a backend that wraps inmem with a deprecation warning,
+	// simulating a backend like S3 whose PrepareConfig warns about
+	// deprecated attributes (e.g. dynamodb_table).
+	backendInit.Set("inmem", func() backend.Backend {
+		return &deprecatedInmemBackend{Backend: inmem.New()}
+	})
+	defer backendInit.Set("inmem", inmem.New)
+
+	td := t.TempDir()
+	testCopyDir(t, testFixturePath("output-backend-with-deprecation"), td)
+	t.Chdir(td)
+
+	// Write the state into the inmem backend's default workspace
+	b := inmem.New()
+	b.Configure(cty.ObjectVal(map[string]cty.Value{
+		"lock_id": cty.NullVal(cty.String),
+	}))
+	sMgr, sDiags := b.StateMgr(backend.DefaultStateName)
+	if sDiags.HasErrors() {
+		t.Fatalf("unexpected error: %s", sDiags.Err())
+	}
+	sMgr.WriteState(originalState)
+	if err := sMgr.PersistState(nil); err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+
+	view, done := testView(t)
+	c := &OutputCommand{
+		Meta: Meta{
+			testingOverrides: metaOverridesForProvider(testProvider()),
+			View:             view,
+		},
+	}
+
+	args := []string{"-raw", "foo"}
+	code := c.Run(args)
+	output := done(t)
+	if code != 0 {
+		t.Fatalf("unexpected exit code %d\nstderr:\n%s", code, output.Stderr())
+	}
+
+	// The key assertion: warnings must not appear in raw output
+	// as they would be indistinguishable from the value.
+	stderr := output.Stderr()
+	if strings.Contains(stderr, "deprecated") {
+		t.Fatalf("warnings should be suppressed, got:\n%s", stderr)
+	}
+
+	actual := strings.TrimSpace(output.Stdout())
+	if actual != `bar` {
+		t.Fatalf("expected output \"bar\", got: %#v", actual)
+	}
+}
diff --git a/internal/command/testdata/output-backend-with-deprecation/.terraform/terraform.tfstate b/internal/command/testdata/output-backend-with-deprecation/.terraform/terraform.tfstate
new file mode 100644
index 0000000000..1c555fbae0
--- /dev/null
+++ b/internal/command/testdata/output-backend-with-deprecation/.terraform/terraform.tfstate
@@ -0,0 +1,12 @@
+{
+    "version": 3,
+    "serial": 0,
+    "lineage": "test-output-deprecation",
+    "backend": {
+        "type": "inmem",
+        "config": {
+            "lock_id": null
+        },
+        "hash": 3947750061
+    }
+}
diff --git a/internal/command/testdata/output-backend-with-deprecation/main.tf b/internal/command/testdata/output-backend-with-deprecation/main.tf
new file mode 100644
index 0000000000..cf5976f8d5
--- /dev/null
+++ b/internal/command/testdata/output-backend-with-deprecation/main.tf
@@ -0,0 +1,7 @@
+terraform {
+    backend "inmem" {}
+}
+
+output "foo" {
+    value = "bar"
+}