Detach captured backend and profile values

internal/domain/smoke_diagnostics.go

@@ -122,15 +122,11 @@ const (
 )
 
 // CloneBackend returns a copy of a backend, including its mutable settings.
-func CloneBackend(backend Backend) (Backend, error) {
+func CloneBackend(backend Backend) Backend {
 	cloned := backend
-	var err error
-	cloned.ExtraParams, err = jsonvalue.CopyMap(backend.ExtraParams)
-	if err != nil {
-		return Backend{}, err
-	}
+	cloned.ExtraParams = jsonvalue.CloneTrusted(backend.ExtraParams).(map[string]any)
 	cloned.SmokeTests = CloneBackendSmokeTestConfig(backend.SmokeTests)
-	return cloned, nil
+	return cloned
 }
 
 // CloneBackendSmokeTestConfig returns an independent copy of optional metadata.

internal/domain/smoke_diagnostics_test.go

@@ -19,10 +19,7 @@ func TestCloneBackendCopiesDiagnosticMetadataAndProviderValues(t *testing.T) {
 		},
 	}
 
-	cloned, err := CloneBackend(backend)
-	if err != nil {
-		t.Fatal(err)
-	}
+	cloned := CloneBackend(backend)
 	*cloned.SmokeTests.DefaultProfile = "changed"
 	*cloned.SmokeTests.Reachability.Endpoint = "changed"
 	*cloned.SmokeTests.Authentication.Kind = "changed"
@@ -37,3 +34,13 @@ func TestCloneBackendCopiesDiagnosticMetadataAndProviderValues(t *testing.T) {
 		t.Fatalf("source provider parameter changed through clone: %v", got)
 	}
 }
+
+func TestCloneBackendPreservesProviderMapPresence(t *testing.T) {
+	if cloned := CloneBackend(Backend{}); cloned.ExtraParams != nil {
+		t.Fatalf("nil provider map became %#v", cloned.ExtraParams)
+	}
+	cloned := CloneBackend(Backend{ExtraParams: map[string]any{"empty": map[string]any{}, "null": nil}})
+	if cloned.ExtraParams == nil || cloned.ExtraParams["empty"].(map[string]any) == nil || cloned.ExtraParams["null"] != nil {
+		t.Fatalf("provider map presence changed: %#v", cloned.ExtraParams)
+	}
+}