From 6f2eb29b29909a4b02978b3af38aabe1a80cb557 Mon Sep 17 00:00:00 2001
From: Matt Dale <9760375+matthewdale@users.noreply.github.com>
Date: Thu, 31 Aug 2023 15:08:22 -0700
Subject: [PATCH] GODRIVER-2603 Use errors.Is/As for IsTimeout and
 IsDuplicateKeyError.

---
 mongo/errors.go                  | 74 +++++++++++++++++---------------
 mongo/integration/client_test.go |  2 +-
 x/mongo/driver/errors.go         |  9 +++-
 3 files changed, 48 insertions(+), 37 deletions(-)

diff --git a/mongo/errors.go b/mongo/errors.go
index 5f2b1b819b..72c3bcc243 100644
--- a/mongo/errors.go
+++ b/mongo/errors.go
@@ -102,50 +102,56 @@ func replaceErrors(err error) error {
 	return err
 }
 
-// IsDuplicateKeyError returns true if err is a duplicate key error
+// IsDuplicateKeyError returns true if err is a duplicate key error.
 func IsDuplicateKeyError(err error) bool {
-	// handles SERVER-7164 and SERVER-11493
-	for ; err != nil; err = unwrap(err) {
-		if e, ok := err.(ServerError); ok {
-			return e.HasErrorCode(11000) || e.HasErrorCode(11001) || e.HasErrorCode(12582) ||
-				e.HasErrorCodeWithMessage(16460, " E11000 ")
-		}
+	if se := ServerError(nil); errors.As(err, &se) {
+		return se.HasErrorCode(11000) || // Duplicate key error.
+			se.HasErrorCode(11001) || // Duplicate key error on update.
+			// Duplicate key error in a capped collection. See SERVER-7164.
+			se.HasErrorCode(12582) ||
+			// Mongos insert error caused by a duplicate key error. See
+			// SERVER-11493.
+			se.HasErrorCodeWithMessage(16460, " E11000 ")
 	}
 	return false
 }
 
-// IsTimeout returns true if err is from a timeout
+// timeoutErrs is a list of error values that indicate a timeout happened.
+var timeoutErrs = [...]error{
+	context.DeadlineExceeded,
+	driver.ErrDeadlineWouldBeExceeded,
+	topology.ErrServerSelectionTimeout,
+}
+
+// IsTimeout returns true if err was caused by a timeout. For error chains,
+// IsTimeout returns true if any error in the chain was caused by a timeout.
 func IsTimeout(err error) bool {
-	for ; err != nil; err = unwrap(err) {
-		// check unwrappable errors together
-		if err == context.DeadlineExceeded {
-			return true
-		}
-		if err == driver.ErrDeadlineWouldBeExceeded {
-			return true
-		}
-		if err == topology.ErrServerSelectionTimeout {
-			return true
-		}
-		if _, ok := err.(topology.WaitQueueTimeoutError); ok {
-			return true
-		}
-		if ce, ok := err.(CommandError); ok && ce.IsMaxTimeMSExpiredError() {
+	// Check if the error chain contains any of the timeout error values.
+	for _, target := range timeoutErrs {
+		if errors.Is(err, target) {
 			return true
 		}
-		if we, ok := err.(WriteException); ok && we.WriteConcernError != nil &&
-			we.WriteConcernError.IsMaxTimeMSExpiredError() {
+	}
+
+	// Check if the error chain contains any error types that can indicate
+	// timeout.
+	if errors.As(err, &topology.WaitQueueTimeoutError{}) {
+		return true
+	}
+	if ce := (CommandError{}); errors.As(err, &ce) && ce.IsMaxTimeMSExpiredError() {
+		return true
+	}
+	if we := (WriteException{}); errors.As(err, &we) && we.WriteConcernError != nil && we.WriteConcernError.IsMaxTimeMSExpiredError() {
+		return true
+	}
+	if ne := net.Error(nil); errors.As(err, &ne) {
+		return ne.Timeout()
+	}
+	// Check timeout error labels.
+	if le := LabeledError(nil); errors.As(err, &le) {
+		if le.HasErrorLabel("NetworkTimeoutError") || le.HasErrorLabel("ExceededTimeLimitError") {
 			return true
 		}
-		if ne, ok := err.(net.Error); ok {
-			return ne.Timeout()
-		}
-		//timeout error labels
-		if le, ok := err.(LabeledError); ok {
-			if le.HasErrorLabel("NetworkTimeoutError") || le.HasErrorLabel("ExceededTimeLimitError") {
-				return true
-			}
-		}
 	}
 
 	return false
diff --git a/mongo/integration/client_test.go b/mongo/integration/client_test.go
index 914ca863b7..561905fb4b 100644
--- a/mongo/integration/client_test.go
+++ b/mongo/integration/client_test.go
@@ -711,7 +711,7 @@ func TestClient(t *testing.T) {
 			err := mt.Client.Ping(ctx, nil)
 			cancel()
 			assert.NotNil(mt, err, "expected Ping to return an error")
-			assert.True(mt, mongo.IsTimeout(err), "expected a timeout error: got %v", err)
+			assert.True(mt, mongo.IsTimeout(err), "expected a timeout error, got: %v", err)
 		}
 
 		// Assert that the Ping timeouts result in no connections being closed.
diff --git a/x/mongo/driver/errors.go b/x/mongo/driver/errors.go
index 55f2fb37eb..177aa1234b 100644
--- a/x/mongo/driver/errors.go
+++ b/x/mongo/driver/errors.go
@@ -264,10 +264,15 @@ func (e Error) UnsupportedStorageEngine() bool {
 
 // Error implements the error interface.
 func (e Error) Error() string {
+	var msg string
 	if e.Name != "" {
-		return fmt.Sprintf("(%v) %v", e.Name, e.Message)
+		msg = fmt.Sprintf("(%v)", e.Name)
 	}
-	return e.Message
+	msg += " " + e.Message
+	if e.Wrapped != nil {
+		msg += ": " + e.Wrapped.Error()
+	}
+	return msg
 }
 
 // Unwrap returns the underlying error.