GODRIVER-2603 (Contd.) Revised error handling using Go 1.13 error APIs (

#1476)

bson/bsoncodec/default_value_decoders.go

@@ -1787,7 +1787,7 @@ func (DefaultValueDecoders) decodeElemsFromDocumentReader(dc DecodeContext, dr b
 	elems := make([]reflect.Value, 0)
 	for {
 		key, vr, err := dr.ReadElement()
-		if err == bsonrw.ErrEOD {
+		if errors.Is(err, bsonrw.ErrEOD) {
 			break
 		}
 		if err != nil {

bson/bsoncodec/default_value_encoders.go

@@ -352,7 +352,7 @@ func (dve DefaultValueEncoders) mapEncodeValue(ec EncodeContext, dw bsonrw.Docum
 			return err
 		}
 
-		if lookupErr == errInvalidValue {
+		if errors.Is(lookupErr, errInvalidValue) {
 			err = vw.WriteNull()
 			if err != nil {
 				return err
@@ -427,7 +427,7 @@ func (dve DefaultValueEncoders) ArrayEncodeValue(ec EncodeContext, vw bsonrw.Val
 			return err
 		}
 
-		if lookupErr == errInvalidValue {
+		if errors.Is(lookupErr, errInvalidValue) {
 			err = vw.WriteNull()
 			if err != nil {
 				return err
@@ -496,7 +496,7 @@ func (dve DefaultValueEncoders) SliceEncodeValue(ec EncodeContext, vw bsonrw.Val
 			return err
 		}
 
-		if lookupErr == errInvalidValue {
+		if errors.Is(lookupErr, errInvalidValue) {
 			err = vw.WriteNull()
 			if err != nil {
 				return err

bson/bsoncodec/map_codec.go

@@ -8,6 +8,7 @@ package bsoncodec
 
 import (
 	"encoding"
+	"errors"
 	"fmt"
 	"reflect"
 	"strconv"
@@ -137,7 +138,7 @@ func (mc *MapCodec) mapEncodeValue(ec EncodeContext, dw bsonrw.DocumentWriter, v
 			return err
 		}
 
-		if lookupErr == errInvalidValue {
+		if errors.Is(lookupErr, errInvalidValue) {
 			err = vw.WriteNull()
 			if err != nil {
 				return err
@@ -200,7 +201,7 @@ func (mc *MapCodec) DecodeValue(dc DecodeContext, vr bsonrw.ValueReader, val ref
 
 	for {
 		key, vr, err := dr.ReadElement()
-		if err == bsonrw.ErrEOD {
+		if errors.Is(err, bsonrw.ErrEOD) {
 			break
 		}
 		if err != nil {

bson/bsoncodec/registry_test.go

@@ -7,6 +7,7 @@
 package bsoncodec
 
 import (
+	"errors"
 	"reflect"
 	"testing"
 
@@ -351,7 +352,8 @@ func TestRegistryBuilder(t *testing.T) {
 					})
 					t.Run("Decoder", func(t *testing.T) {
 						wanterr := tc.wanterr
-						if ene, ok := tc.wanterr.(ErrNoEncoder); ok {
+						var ene ErrNoEncoder
+						if errors.As(tc.wanterr, &ene) {
 							wanterr = ErrNoDecoder(ene)
 						}
 
@@ -775,7 +777,8 @@ func TestRegistry(t *testing.T) {
 						t.Parallel()
 
 						wanterr := tc.wanterr
-						if ene, ok := tc.wanterr.(ErrNoEncoder); ok {
+						var ene ErrNoEncoder
+						if errors.As(tc.wanterr, &ene) {
 							wanterr = ErrNoDecoder(ene)
 						}
 

bson/bsonrw/copier.go

@@ -7,6 +7,7 @@
 package bsonrw
 
 import (
+	"errors"
 	"fmt"
 	"io"
 
@@ -442,7 +443,7 @@ func (c Copier) copyArray(dst ValueWriter, src ValueReader) error {
 
 	for {
 		vr, err := ar.ReadValue()
-		if err == ErrEOA {
+		if errors.Is(err, ErrEOA) {
 			break
 		}
 		if err != nil {
@@ -466,7 +467,7 @@ func (c Copier) copyArray(dst ValueWriter, src ValueReader) error {
 func (c Copier) copyDocumentCore(dw DocumentWriter, dr DocumentReader) error {
 	for {
 		key, vr, err := dr.ReadElement()
-		if err == ErrEOD {
+		if errors.Is(err, ErrEOD) {
 			break
 		}
 		if err != nil {

bson/bsonrw/extjson_parser.go

@@ -313,7 +313,7 @@ func (ejp *extJSONParser) readValue(t bsontype.Type) (*extJSONValue, error) {
 				// convert hex to bytes
 				bytes, err := hex.DecodeString(uuidNoHyphens)
 				if err != nil {
-					return nil, fmt.Errorf("$uuid value does not follow RFC 4122 format regarding hex bytes: %v", err)
+					return nil, fmt.Errorf("$uuid value does not follow RFC 4122 format regarding hex bytes: %w", err)
 				}
 
 				ejp.advanceState()

bson/bsonrw/extjson_parser_test.go

@@ -7,6 +7,7 @@
 package bsonrw
 
 import (
+	"errors"
 	"io"
 	"strings"
 	"testing"
@@ -47,7 +48,7 @@ type readKeyValueTestCase struct {
 
 func expectSpecificError(expected error) expectedErrorFunc {
 	return func(t *testing.T, err error, desc string) {
-		if err != expected {
+		if !errors.Is(err, expected) {
 			t.Helper()
 			t.Errorf("%s: Expected %v but got: %v", desc, expected, err)
 			t.FailNow()

bson/bsonrw/extjson_reader.go

@@ -7,6 +7,7 @@
 package bsonrw
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"sync"
@@ -613,7 +614,7 @@ func (ejvr *extJSONValueReader) ReadElement() (string, ValueReader, error) {
 	name, t, err := ejvr.p.readKey()
 
 	if err != nil {
-		if err == ErrEOD {
+		if errors.Is(err, ErrEOD) {
 			if ejvr.stack[ejvr.frame].mode == mCodeWithScope {
 				_, err := ejvr.p.peekType()
 				if err != nil {
@@ -640,7 +641,7 @@ func (ejvr *extJSONValueReader) ReadValue() (ValueReader, error) {
 
 	t, err := ejvr.p.peekType()
 	if err != nil {
-		if err == ErrEOA {
+		if errors.Is(err, ErrEOA) {
 			ejvr.pop()
 		}
 

bson/bsonrw/json_scanner.go

@@ -58,7 +58,7 @@ func (js *jsonScanner) nextToken() (*jsonToken, error) {
 		c, err = js.readNextByte()
 	}
 
-	if err == io.EOF {
+	if errors.Is(err, io.EOF) {
 		return &jsonToken{t: jttEOF}, nil
 	} else if err != nil {
 		return nil, err
@@ -198,7 +198,7 @@ func (js *jsonScanner) scanString() (*jsonToken, error) {
 	for {
 		c, err = js.readNextByte()
 		if err != nil {
-			if err == io.EOF {
+			if errors.Is(err, io.EOF) {
 				return nil, errors.New("end of input in JSON string")
 			}
 			return nil, err
@@ -209,7 +209,7 @@ func (js *jsonScanner) scanString() (*jsonToken, error) {
 		case '\\':
 			c, err = js.readNextByte()
 			if err != nil {
-				if err == io.EOF {
+				if errors.Is(err, io.EOF) {
 					return nil, errors.New("end of input in JSON string")
 				}
 				return nil, err
@@ -248,7 +248,7 @@ func (js *jsonScanner) scanString() (*jsonToken, error) {
 				if utf16.IsSurrogate(rn) {
 					c, err = js.readNextByte()
 					if err != nil {
-						if err == io.EOF {
+						if errors.Is(err, io.EOF) {
 							return nil, errors.New("end of input in JSON string")
 						}
 						return nil, err
@@ -264,7 +264,7 @@ func (js *jsonScanner) scanString() (*jsonToken, error) {
 
 					c, err = js.readNextByte()
 					if err != nil {
-						if err == io.EOF {
+						if errors.Is(err, io.EOF) {
 							return nil, errors.New("end of input in JSON string")
 						}
 						return nil, err
@@ -384,7 +384,7 @@ func (js *jsonScanner) scanNumber(first byte) (*jsonToken, error) {
 	for {
 		c, err = js.readNextByte()
 
-		if err != nil && err != io.EOF {
+		if err != nil && !errors.Is(err, io.EOF) {
 			return nil, err
 		}
 

bson/bsonrw/value_reader_test.go

@@ -8,6 +8,7 @@ package bsonrw
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"io"
 	"math"
@@ -185,7 +186,7 @@ func TestValueReader(t *testing.T) {
 			// invalid length
 			vr.d = []byte{0x00, 0x00}
 			_, err := vr.ReadDocument()
-			if err != io.EOF {
+			if !errors.Is(err, io.EOF) {
 				t.Errorf("Expected io.EOF with document length too small. got %v; want %v", err, io.EOF)
 			}
 
@@ -239,7 +240,7 @@ func TestValueReader(t *testing.T) {
 
 			vr.frame--
 			_, err = vr.ReadDocument()
-			if err != io.EOF {
+			if !errors.Is(err, io.EOF) {
 				t.Errorf("Should return error when attempting to read length with not enough bytes. got %v; want %v", err, io.EOF)
 			}
 		})
@@ -1482,7 +1483,7 @@ func TestValueReader(t *testing.T) {
 						frame: 0,
 					}
 					gotType, got, gotErr := vr.ReadValueBytes(nil)
-					if gotErr != tc.wantErr {
+					if !errors.Is(gotErr, tc.wantErr) {
 						t.Errorf("Did not receive expected error. got %v; want %v", gotErr, tc.wantErr)
 					}
 					if tc.wantErr == nil && gotType != tc.wantType {

bson/decoder_test.go

@@ -279,7 +279,7 @@ func TestDecoderv2(t *testing.T) {
 
 		var got *D
 		err = dec.Decode(got)
-		if err != ErrDecodeToNil {
+		if !errors.Is(err, ErrDecodeToNil) {
 			t.Fatalf("Decode error mismatch; expected %v, got %v", ErrDecodeToNil, err)
 		}
 	})

bson/primitive_codecs_test.go

@@ -28,7 +28,7 @@ import (
 func bytesFromDoc(doc interface{}) []byte {
 	b, err := Marshal(doc)
 	if err != nil {
-		panic(fmt.Errorf("Couldn't marshal BSON document: %v", err))
+		panic(fmt.Errorf("Couldn't marshal BSON document: %w", err))
 	}
 	return b
 }
@@ -471,7 +471,7 @@ func TestDefaultValueEncoders(t *testing.T) {
 				enc, err := NewEncoder(vw)
 				noerr(t, err)
 				err = enc.Encode(tc.value)
-				if err != tc.err {
+				if !errors.Is(err, tc.err) {
 					t.Errorf("Did not receive expected error. got %v; want %v", err, tc.err)
 				}
 				if diff := cmp.Diff([]byte(b), tc.b); diff != "" {

bson/raw_test.go

@@ -9,6 +9,7 @@ package bson
 import (
 	"bytes"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io"
 	"strings"
@@ -52,7 +53,7 @@ func TestRaw(t *testing.T) {
 			r := make(Raw, 5)
 			binary.LittleEndian.PutUint32(r[0:4], 200)
 			got := r.Validate()
-			if got != want {
+			if !errors.Is(got, want) {
 				t.Errorf("Did not get expected error. got %v; want %v", got, want)
 			}
 		})
@@ -62,7 +63,7 @@ func TestRaw(t *testing.T) {
 			binary.LittleEndian.PutUint32(r[0:4], 8)
 			r[4], r[5], r[6], r[7] = '\x02', 'f', 'o', 'o'
 			got := r.Validate()
-			if got != want {
+			if !errors.Is(got, want) {
 				t.Errorf("Did not get expected error. got %v; want %v", got, want)
 			}
 		})
@@ -72,7 +73,7 @@ func TestRaw(t *testing.T) {
 			binary.LittleEndian.PutUint32(r[0:4], 9)
 			r[4], r[5], r[6], r[7], r[8] = '\x0A', 'f', 'o', 'o', '\x00'
 			got := r.Validate()
-			if got != want {
+			if !errors.Is(got, want) {
 				t.Errorf("Did not get expected error. got %v; want %v", got, want)
 			}
 		})

examples/documentation_examples/examples.go

@@ -8,6 +8,7 @@ package documentation_examples
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io/ioutil"
 	logger "log"
@@ -1816,7 +1817,8 @@ func RunTransactionWithRetry(sctx mongo.SessionContext, txnFn func(mongo.Session
 		log.Println("Transaction aborted. Caught exception during transaction.")
 
 		// If transient error, retry the whole transaction
-		if cmdErr, ok := err.(mongo.CommandError); ok && cmdErr.HasErrorLabel("TransientTransactionError") {
+		var cmdErr mongo.CommandError
+		if errors.As(err, &cmdErr) && cmdErr.HasErrorLabel("TransientTransactionError") {
 			log.Println("TransientTransactionError, retrying transaction...")
 			continue
 		}
@@ -1883,7 +1885,8 @@ func TransactionsExamples(ctx context.Context, client *mongo.Client) error {
 			log.Println("Transaction aborted. Caught exception during transaction.")
 
 			// If transient error, retry the whole transaction
-			if cmdErr, ok := err.(mongo.CommandError); ok && cmdErr.HasErrorLabel("TransientTransactionError") {
+			var cmdErr mongo.CommandError
+			if errors.As(err, &cmdErr) && cmdErr.HasErrorLabel("TransientTransactionError") {
 				log.Println("TransientTransactionError, retrying transaction...")
 				continue
 			}

internal/logger/logger.go

@@ -183,7 +183,7 @@ func selectLogSink(sink LogSink) (LogSink, *os.File, error) {
 	if path != "" {
 		logFile, err := os.OpenFile(path, os.O_APPEND|os.O_CREATE|os.O_RDWR, 0666)
 		if err != nil {
-			return nil, nil, fmt.Errorf("unable to open log file: %v", err)
+			return nil, nil, fmt.Errorf("unable to open log file: %w", err)
 		}
 
 		return NewIOSink(logFile), logFile, nil

mongo/bulk_write.go

@@ -8,6 +8,7 @@ package mongo
 
 import (
 	"context"
+	"errors"
 
 	"go.mongodb.org/mongo-driver/bson/bsoncodec"
 	"go.mongodb.org/mongo-driver/bson/primitive"
@@ -108,8 +109,8 @@ func (bw *bulkWrite) runBatch(ctx context.Context, batch bulkWriteBatch) (BulkWr
 	case *InsertOneModel:
 		res, err := bw.runInsert(ctx, batch)
 		if err != nil {
-			writeErr, ok := err.(driver.WriteCommandError)
-			if !ok {
+			var writeErr driver.WriteCommandError
+			if !errors.As(err, &writeErr) {
 				return BulkWriteResult{}, batchErr, err
 			}
 			writeErrors = writeErr.WriteErrors
@@ -120,8 +121,8 @@ func (bw *bulkWrite) runBatch(ctx context.Context, batch bulkWriteBatch) (BulkWr
 	case *DeleteOneModel, *DeleteManyModel:
 		res, err := bw.runDelete(ctx, batch)
 		if err != nil {
-			writeErr, ok := err.(driver.WriteCommandError)
-			if !ok {
+			var writeErr driver.WriteCommandError
+			if !errors.As(err, &writeErr) {
 				return BulkWriteResult{}, batchErr, err
 			}
 			writeErrors = writeErr.WriteErrors
@@ -132,8 +133,8 @@ func (bw *bulkWrite) runBatch(ctx context.Context, batch bulkWriteBatch) (BulkWr
 	case *ReplaceOneModel, *UpdateOneModel, *UpdateManyModel:
 		res, err := bw.runUpdate(ctx, batch)
 		if err != nil {
-			writeErr, ok := err.(driver.WriteCommandError)
-			if !ok {
+			var writeErr driver.WriteCommandError
+			if !errors.As(err, &writeErr) {
 				return BulkWriteResult{}, batchErr, err
 			}
 			writeErrors = writeErr.WriteErrors