fix: preserve native context sentinels in errgrpc ToNative

pkg/errgrpc/grpc.go

@@ -222,7 +222,17 @@ func ToNative(err error) error {
 		code = s.Code()
 	} else {
 		desc = err.Error()
-		code = codes.Unknown
+		// No gRPC status: default to Unknown, but map native context
+		// sentinels to their code so the switch below restores them
+		// instead of reclassifying as errdefs.ErrUnknown.
+		switch {
+		case errors.Is(err, context.DeadlineExceeded):
+			code = codes.DeadlineExceeded
+		case errors.Is(err, context.Canceled):
+			code = codes.Canceled
+		default:
+			code = codes.Unknown
+		}
 	}
 
 	var cls error // divide these into error classes, becomes the cause

pkg/errgrpc/grpc_test.go

@@ -274,3 +274,72 @@ func TestGRPCNestedError(t *testing.T) {
 
 	checkError(ToNative(ToGRPC(werr)))
 }
+
+
+// TestToNativeContextSentinels verifies that ToNative preserves the identity
+// of native context sentinels (context.DeadlineExceeded and context.Canceled)
+// when they are passed directly, without first being mapped to a gRPC status
+// error via ToGRPC. This is the path taken when a ttrpc/gRPC client returns
+// ctx.Err() on a per-call deadline and the caller runs it through ToNative.
+//
+// Unlike TestGRPCRoundTrip, these cases do NOT go through ToGRPC first, so
+// status.FromError reports codes.Unknown. Without preserving the sentinel,
+// the result wraps errdefs.ErrUnknown and errdefs.IsDeadlineExceeded /
+// errdefs.IsCanceled stop recognizing it.
+func TestToNativeContextSentinels(t *testing.T) {
+	for _, testcase := range []struct {
+		name  string
+		input error
+		cause error
+		is    func(error) bool
+		str   string
+	}{
+		{
+			name:  "bare deadline exceeded",
+			input: context.DeadlineExceeded,
+			cause: context.DeadlineExceeded,
+			is:    errdefs.IsDeadlineExceeded,
+			str:   "context deadline exceeded",
+		},
+		{
+			name:  "wrapped deadline exceeded",
+			input: fmt.Errorf("get state for abc: %w", context.DeadlineExceeded),
+			cause: context.DeadlineExceeded,
+			is:    errdefs.IsDeadlineExceeded,
+			str:   "get state for abc: context deadline exceeded",
+		},
+		{
+			name:  "bare canceled",
+			input: context.Canceled,
+			cause: context.Canceled,
+			is:    errdefs.IsCanceled,
+			str:   "context canceled",
+		},
+		{
+			name:  "wrapped canceled",
+			input: fmt.Errorf("operation aborted: %w", context.Canceled),
+			cause: context.Canceled,
+			is:    errdefs.IsCanceled,
+			str:   "operation aborted: context canceled",
+		},
+	} {
+		t.Run(testcase.name, func(t *testing.T) {
+			nerr := ToNative(testcase.input)
+			t.Logf("input: %v, recovered: %v", testcase.input, nerr)
+
+			if !errors.Is(nerr, testcase.cause) {
+				t.Fatalf("unexpected cause: !errors.Is(%v, %v)", nerr, testcase.cause)
+			}
+			if !testcase.is(nerr) {
+				t.Fatalf("errdefs Is helper did not match recovered error: %v", nerr)
+			}
+			// The sentinel must not be reclassified as an unknown error.
+			if errdefs.IsUnknown(nerr) {
+				t.Fatalf("recovered error misclassified as unknown: %v", nerr)
+			}
+			if nerr.Error() != testcase.str {
+				t.Fatalf("unexpected string: %q != %q", nerr.Error(), testcase.str)
+			}
+		})
+	}
+}

pkg/go.sum

@@ -1,5 +1,5 @@
-github.com/containerd/errdefs v0.3.0 h1:FSZgGOeK4yuT/+DnF07/Olde/q4KBoMsaamhXxIMDp4=
-github.com/containerd/errdefs v0.3.0/go.mod h1:+YBYIdtsnF4Iw6nWZhJcqGSg/dwvV7tyJ/kCkyJ2k+M=
+github.com/containerd/errdefs v1.0.0 h1:tg5yIfIlQIrxYtu9ajqY42W3lpS19XqdxRQeEwYG8PI=
+github.com/containerd/errdefs v1.0.0/go.mod h1:+YBYIdtsnF4Iw6nWZhJcqGSg/dwvV7tyJ/kCkyJ2k+M=
 github.com/containerd/typeurl/v2 v2.3.0 h1:HZHPhRWo5XMy3QGQoPrUzbW/2ckwjfweHmOwlkIrPAQ=
 github.com/containerd/typeurl/v2 v2.3.0/go.mod h1:Qk+PAdUYArVj41TnGi6rJ+48RF0PkcTc4i/taoBcK0w=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=