Update dependencies

vendor/github.com/cockroachdb/errors/errbase/decode.go

@@ -57,6 +57,15 @@ func decodeLeaf(ctx context.Context, enc *errorspb.EncodedErrorLeaf) error {
 			return genErr
 		}
 		// Decoding failed, we'll drop through to opaqueLeaf{} below.
+	} else if decoder, ok := multiCauseDecoders[typeKey]; ok {
+		causes := make([]error, len(enc.MultierrorCauses))
+		for i, e := range enc.MultierrorCauses {
+			causes[i] = DecodeError(ctx, *e)
+		}
+		genErr := decoder(ctx, causes, enc.Message, enc.Details.ReportablePayload, payload)
+		if genErr != nil {
+			return genErr
+		}
 	} else {
 		// Shortcut for non-registered proto-encodable error types:
 		// if it already implements `error`, it's good to go.
@@ -66,6 +75,19 @@ func decodeLeaf(ctx context.Context, enc *errorspb.EncodedErrorLeaf) error {
 		}
 	}
 
+	if len(enc.MultierrorCauses) > 0 {
+		causes := make([]error, len(enc.MultierrorCauses))
+		for i, e := range enc.MultierrorCauses {
+			causes[i] = DecodeError(ctx, *e)
+		}
+		leaf := &opaqueLeafCauses{
+			causes: causes,
+		}
+		leaf.msg = enc.Message
+		leaf.details = enc.Details
+		return leaf
+	}
+
 	// No decoder and no error type: we'll keep what we received and
 	// make it ready to re-encode exactly (if the error leaves over the
 	// network again).
@@ -97,7 +119,7 @@ func decodeWrapper(ctx context.Context, enc *errorspb.EncodedWrapper) error {
 	typeKey := TypeKey(enc.Details.ErrorTypeMark.FamilyName)
 	if decoder, ok := decoders[typeKey]; ok {
 		// Yes, use it.
-		genErr := decoder(ctx, cause, enc.MessagePrefix, enc.Details.ReportablePayload, payload)
+		genErr := decoder(ctx, cause, enc.Message, enc.Details.ReportablePayload, payload)
 		if genErr != nil {
 			// Decoding succeeded. Use this.
 			return genErr
@@ -107,9 +129,10 @@ func decodeWrapper(ctx context.Context, enc *errorspb.EncodedWrapper) error {
 
 	// Otherwise, preserve all details about the original object.
 	return &opaqueWrapper{
-		cause:   cause,
-		prefix:  enc.MessagePrefix,
-		details: enc.Details,
+		cause:       cause,
+		prefix:      enc.Message,
+		details:     enc.Details,
+		messageType: MessageType(enc.MessageType),
 	}
 }
 
@@ -160,3 +183,24 @@ type WrapperDecoder = func(ctx context.Context, cause error, msgPrefix string, s
 
 // registry for RegisterWrapperType.
 var decoders = map[TypeKey]WrapperDecoder{}
+
+// MultiCauseDecoder is to be provided (via RegisterMultiCauseDecoder
+// above) by additional multi-cause wrapper types not yet known by the
+// library. A nil return indicates that decoding was not successful.
+type MultiCauseDecoder = func(ctx context.Context, causes []error, msgPrefix string, safeDetails []string, payload proto.Message) error
+
+// registry for RegisterMultiCauseDecoder.
+var multiCauseDecoders = map[TypeKey]MultiCauseDecoder{}
+
+// RegisterMultiCauseDecoder can be used to register new multi-cause
+// wrapper types to the library. Registered wrappers will be decoded
+// using their own Go type when an error is decoded. Multi-cause
+// wrappers that have not been registered will be decoded using the
+// opaqueWrapper type.
+func RegisterMultiCauseDecoder(theType TypeKey, decoder MultiCauseDecoder) {
+	if decoder == nil {
+		delete(multiCauseDecoders, theType)
+	} else {
+		multiCauseDecoders[theType] = decoder
+	}
+}

vendor/github.com/cockroachdb/errors/errbase/encode.go

@@ -33,18 +33,24 @@ func EncodeError(ctx context.Context, err error) EncodedError {
 	if cause := UnwrapOnce(err); cause != nil {
 		return encodeWrapper(ctx, err, cause)
 	}
-	// Not a causer.
-	return encodeLeaf(ctx, err)
+	return encodeLeaf(ctx, err, UnwrapMulti(err))
 }
 
-// encodeLeaf encodes a leaf error.
-func encodeLeaf(ctx context.Context, err error) EncodedError {
+// encodeLeaf encodes a leaf error. This function accepts a `causes`
+// argument because we encode multi-cause errors using the Leaf
+// protobuf. This was done to enable backwards compatibility when
+// introducing this functionality since the Wrapper type already has a
+// required single `cause` field.
+func encodeLeaf(ctx context.Context, err error, causes []error) EncodedError {
 	var msg string
 	var details errorspb.EncodedErrorDetails
 
 	if e, ok := err.(*opaqueLeaf); ok {
 		msg = e.msg
 		details = e.details
+	} else if e, ok := err.(*opaqueLeafCauses); ok {
+		msg = e.msg
+		details = e.details
 	} else {
 		details.OriginalTypeName, details.ErrorTypeMark.FamilyName, details.ErrorTypeMark.Extension = getTypeDetails(err, false /*onlyFamily*/)
 
@@ -74,11 +80,21 @@ func encodeLeaf(ctx context.Context, err error) EncodedError {
 		details.FullDetails = encodeAsAny(ctx, err, payload)
 	}
 
+	var cs []*EncodedError
+	if len(causes) > 0 {
+		cs = make([]*EncodedError, len(causes))
+		for i, ee := range causes {
+			ee := EncodeError(ctx, ee)
+			cs[i] = &ee
+		}
+	}
+
 	return EncodedError{
 		Error: &errorspb.EncodedError_Leaf{
 			Leaf: &errorspb.EncodedErrorLeaf{
-				Message: msg,
-				Details: details,
+				Message:          msg,
+				Details:          details,
+				MultierrorCauses: cs,
 			},
 		},
 	}
@@ -115,10 +131,18 @@ func encodeAsAny(ctx context.Context, err error, payload proto.Message) *types.A
 func encodeWrapper(ctx context.Context, err, cause error) EncodedError {
 	var msg string
 	var details errorspb.EncodedErrorDetails
+	messageType := Prefix
 
 	if e, ok := err.(*opaqueWrapper); ok {
+		// We delegate all knowledge of the error string
+		// to the original encoder and do not try to re-engineer
+		// the prefix out of the error. This helps maintain
+		// backward compatibility with earlier versions of the
+		// encoder which don't have any understanding of
+		// error string ownership by the wrapper.
 		msg = e.prefix
 		details = e.details
+		messageType = e.messageType
 	} else {
 		details.OriginalTypeName, details.ErrorTypeMark.FamilyName, details.ErrorTypeMark.Extension = getTypeDetails(err, false /*onlyFamily*/)
 
@@ -127,12 +151,12 @@ func encodeWrapper(ctx context.Context, err, cause error) EncodedError {
 		// If we have a manually registered encoder, use that.
 		typeKey := TypeKey(details.ErrorTypeMark.FamilyName)
 		if enc, ok := encoders[typeKey]; ok {
-			msg, details.ReportablePayload, payload = enc(ctx, err)
+			msg, details.ReportablePayload, payload, messageType = enc(ctx, err)
 		} else {
 			// No encoder.
 			// In that case, we'll try to compute a message prefix
 			// manually.
-			msg = extractPrefix(err, cause)
+			msg, messageType = extractPrefix(err, cause)
 
 			// If there are known safe details, use them.
 			if s, ok := err.(SafeDetailer); ok {
@@ -148,9 +172,10 @@ func encodeWrapper(ctx context.Context, err, cause error) EncodedError {
 	return EncodedError{
 		Error: &errorspb.EncodedError_Wrapper{
 			Wrapper: &errorspb.EncodedWrapper{
-				Cause:         EncodeError(ctx, cause),
-				MessagePrefix: msg,
-				Details:       details,
+				Cause:       EncodeError(ctx, cause),
+				Message:     msg,
+				Details:     details,
+				MessageType: errorspb.MessageType(messageType),
 			},
 		},
 	}
@@ -158,21 +183,36 @@ func encodeWrapper(ctx context.Context, err, cause error) EncodedError {
 
 // extractPrefix extracts the prefix from a wrapper's error message.
 // For example,
-//    err := errors.New("bar")
-//    err = errors.Wrap(err, "foo")
-//    extractPrefix(err)
+//
+//	err := errors.New("bar")
+//	err = errors.Wrap(err, "foo")
+//	extractPrefix(err)
+//
 // returns "foo".
-func extractPrefix(err, cause error) string {
+//
+// If a presumed wrapper does not have a message prefix, it is assumed
+// to override the entire error message and `extractPrefix` returns
+// the entire message and the boolean `true` to signify that the causes
+// should not be appended to it.
+func extractPrefix(err, cause error) (string, MessageType) {
 	causeSuffix := cause.Error()
 	errMsg := err.Error()
 
 	if strings.HasSuffix(errMsg, causeSuffix) {
 		prefix := errMsg[:len(errMsg)-len(causeSuffix)]
+		// If error msg matches exactly then this is a wrapper
+		// with no message of its own.
+		if len(prefix) == 0 {
+			return "", Prefix
+		}
 		if strings.HasSuffix(prefix, ": ") {
-			return prefix[:len(prefix)-2]
+			return prefix[:len(prefix)-2], Prefix
 		}
 	}
-	return ""
+	// If we don't have the cause as a suffix, then we have
+	// some other string as our error msg, preserve that and
+	// mark as override
+	return errMsg, FullMessage
 }
 
 func getTypeDetails(
@@ -183,6 +223,8 @@ func getTypeDetails(
 	switch t := err.(type) {
 	case *opaqueLeaf:
 		return t.details.OriginalTypeName, t.details.ErrorTypeMark.FamilyName, t.details.ErrorTypeMark.Extension
+	case *opaqueLeafCauses:
+		return t.details.OriginalTypeName, t.details.ErrorTypeMark.FamilyName, t.details.ErrorTypeMark.Extension
 	case *opaqueWrapper:
 		return t.details.OriginalTypeName, t.details.ErrorTypeMark.FamilyName, t.details.ErrorTypeMark.Extension
 	}
@@ -286,6 +328,28 @@ type LeafEncoder = func(ctx context.Context, err error) (msg string, safeDetails
 // registry for RegisterLeafEncoder.
 var leafEncoders = map[TypeKey]LeafEncoder{}
 
+// RegisterMultiCauseEncoder can be used to register new multi-cause
+// error types to the library. Registered types will be encoded using
+// their own Go type when an error is encoded. Multi-cause wrappers
+// that have not been registered will be encoded using the
+// opaqueWrapper type.
+func RegisterMultiCauseEncoder(theType TypeKey, encoder MultiCauseEncoder) {
+	// This implementation is a simple wrapper around `LeafEncoder`
+	// because we implemented multi-cause error wrapper encoding into a
+	// `Leaf` instead of a `Wrapper` for smoother backwards
+	// compatibility support. Exposing this detail to consumers of the
+	// API is confusing and hence avoided. The causes of the error are
+	// encoded separately regardless of this encoder's implementation.
+	RegisterLeafEncoder(theType, encoder)
+}
+
+// MultiCauseEncoder is to be provided (via RegisterMultiCauseEncoder
+// above) by additional multi-cause wrapper types not yet known to this
+// library. The encoder will automatically extract and encode the
+// causes of this error by calling `Unwrap()` and expecting a slice of
+// errors.
+type MultiCauseEncoder = func(ctx context.Context, err error) (msg string, safeDetails []string, payload proto.Message)
+
 // RegisterWrapperEncoder can be used to register new wrapper types to
 // the library. Registered wrappers will be encoded using their own
 // Go type when an error is encoded. Wrappers that have not been
@@ -295,6 +359,35 @@ var leafEncoders = map[TypeKey]LeafEncoder{}
 // or a different type, ensure that RegisterTypeMigration() was called
 // prior to RegisterWrapperEncoder().
 func RegisterWrapperEncoder(theType TypeKey, encoder WrapperEncoder) {
+	RegisterWrapperEncoderWithMessageType(
+		theType,
+		func(ctx context.Context, err error) (
+			msgPrefix string,
+			safeDetails []string,
+			payload proto.Message,
+			messageType MessageType,
+		) {
+			prefix, details, payload := encoder(ctx, err)
+			return prefix, details, payload, messageType
+		})
+}
+
+// RegisterWrapperEncoderWithMessageType can be used to register
+// new wrapper types to the library. Registered wrappers will be
+// encoded using their own Go type when an error is encoded. Wrappers
+// that have not been registered will be encoded using the
+// opaqueWrapper type.
+//
+// This function differs from RegisterWrapperEncoder by allowing the
+// caller to explicitly decide whether the wrapper owns the entire
+// error message or not. Otherwise, the relationship is inferred.
+//
+// Note: if the error type has been migrated from a previous location
+// or a different type, ensure that RegisterTypeMigration() was called
+// prior to RegisterWrapperEncoder().
+func RegisterWrapperEncoderWithMessageType(
+	theType TypeKey, encoder WrapperEncoderWithMessageType,
+) {
 	if encoder == nil {
 		delete(encoders, theType)
 	} else {
@@ -304,7 +397,42 @@ func RegisterWrapperEncoder(theType TypeKey, encoder WrapperEncoder) {
 
 // WrapperEncoder is to be provided (via RegisterWrapperEncoder above)
 // by additional wrapper types not yet known to this library.
-type WrapperEncoder = func(ctx context.Context, err error) (msgPrefix string, safeDetails []string, payload proto.Message)
+type WrapperEncoder func(ctx context.Context, err error) (
+	msgPrefix string,
+	safeDetails []string,
+	payload proto.Message,
+)
+
+// MessageType is used to encode information about an error message
+// within a wrapper error type. This information is used to affect
+// display logic.
+type MessageType errorspb.MessageType
+
+// Values below should match the ones in errorspb.MessageType for
+// direct conversion.
+const (
+	// Prefix denotes an error message that should be prepended to the
+	// message of its cause.
+	Prefix MessageType = MessageType(errorspb.MessageType_PREFIX)
+	// FullMessage denotes an error message that contains the text of its
+	// causes and can be displayed standalone.
+	FullMessage = MessageType(errorspb.MessageType_FULL_MESSAGE)
+)
+
+// WrapperEncoderWithMessageType is to be provided (via
+// RegisterWrapperEncoderWithMessageType above) by additional wrapper
+// types not yet known to this library. This encoder returns an
+// additional enum which indicates whether the wrapper owns the error
+// message completely instead of simply being a prefix with the error
+// message of its causes appended to it. This information is encoded
+// along with the prefix in order to provide context during error
+// display.
+type WrapperEncoderWithMessageType func(ctx context.Context, err error) (
+	msgPrefix string,
+	safeDetails []string,
+	payload proto.Message,
+	messageType MessageType,
+)
 
 // registry for RegisterWrapperType.
-var encoders = map[TypeKey]WrapperEncoder{}
+var encoders = map[TypeKey]WrapperEncoderWithMessageType{}

vendor/github.com/cockroachdb/errors/errbase/format_error.go

@@ -102,7 +102,13 @@ func formatErrorInternal(err error, s fmt.State, verb rune, redactableOutput boo
 		// to enable stack trace de-duplication. This requires a
 		// post-order traversal. Since we have a linked list, the best we
 		// can do is a recursion.
-		p.formatRecursive(err, true /* isOutermost */, true /* withDetail */)
+		p.formatRecursive(
+			err,
+			true,  /* isOutermost */
+			true,  /* withDetail */
+			false, /* withDepth */
+			0,     /* depth */
+		)
 
 		// We now have all the data, we can render the result.
 		p.formatEntries(err)
@@ -146,7 +152,13 @@ func formatErrorInternal(err error, s fmt.State, verb rune, redactableOutput boo
 		// by calling FormatError(), in which case we'd get an infinite
 		// recursion. So we have no choice but to peel the data
 		// and then assemble the pieces ourselves.
-		p.formatRecursive(err, true /* isOutermost */, false /* withDetail */)
+		p.formatRecursive(
+			err,
+			true,  /* isOutermost */
+			false, /* withDetail */
+			false, /* withDepth */
+			0,     /* depth */
+		)
 		p.formatSingleLineOutput()
 		p.finishDisplay(verb)
 
@@ -195,7 +207,19 @@ func (s *state) formatEntries(err error) {
 	// Wraps: (N) <details>
 	//
 	for i, j := len(s.entries)-2, 2; i >= 0; i, j = i-1, j+1 {
-		fmt.Fprintf(&s.finalBuf, "\nWraps: (%d)", j)
+		s.finalBuf.WriteByte('\n')
+		// Extra indentation starts at depth==2 because the direct
+		// children of the root error area already printed on separate
+		// newlines.
+		for m := 0; m < s.entries[i].depth-1; m += 1 {
+			if m == s.entries[i].depth-2 {
+				s.finalBuf.WriteString("└─ ")
+			} else {
+				s.finalBuf.WriteByte(' ')
+				s.finalBuf.WriteByte(' ')
+			}
+		}
+		fmt.Fprintf(&s.finalBuf, "Wraps: (%d)", j)
 		entry := s.entries[i]
 		s.printEntry(entry)
 	}
@@ -278,8 +302,9 @@ func (s *state) printEntry(entry formatEntry) {
 //
 // This function is used both when FormatError() is called indirectly
 // from .Error(), e.g. in:
-//      (e *myType) Error() { return fmt.Sprintf("%v", e) }
-//      (e *myType) Format(s fmt.State, verb rune) { errors.FormatError(s, verb, e) }
+//
+//	(e *myType) Error() { return fmt.Sprintf("%v", e) }
+//	(e *myType) Format(s fmt.State, verb rune) { errors.FormatError(s, verb, e) }
 //
 // and also to print the first line in the output of a %+v format.
 //
@@ -329,13 +354,35 @@ func (s *state) formatSingleLineOutput() {
 // s.finalBuf is untouched. The conversion of s.entries
 // to s.finalBuf is done by formatSingleLineOutput() and/or
 // formatEntries().
-func (s *state) formatRecursive(err error, isOutermost, withDetail bool) {
+//
+// `withDepth` and `depth` are used to tag subtrees of multi-cause
+// errors for added indentation during printing. Once a multi-cause
+// error is encountered, all subsequent calls with set `withDepth` to
+// true, and increment `depth` during recursion. This information is
+// persisted into the generated entries and used later to display the
+// error with increased indentation based in the depth.
+func (s *state) formatRecursive(err error, isOutermost, withDetail, withDepth bool, depth int) int {
 	cause := UnwrapOnce(err)
+	numChildren := 0
 	if cause != nil {
-		// Recurse first.
-		s.formatRecursive(cause, false /*isOutermost*/, withDetail)
+		// Recurse first, which populates entries list starting from innermost
+		// entry. If we've previously seen a multi-cause wrapper, `withDepth`
+		// will be true, and we'll record the depth below ensuring that extra
+		// indentation is applied to this inner cause during printing.
+		// Otherwise, we maintain "straight" vertical formatting by keeping the
+		// parent callers `withDepth` value of `false` by default.
+		numChildren += s.formatRecursive(cause, false, withDetail, withDepth, depth+1)
 	}
 
+	causes := UnwrapMulti(err)
+	for _, c := range causes {
+		// Override `withDepth` to true for all child entries ensuring they have
+		// indentation applied during formatting to distinguish them from
+		// parents.
+		numChildren += s.formatRecursive(c, false, withDetail, true, depth+1)
+	}
+	// inserted := len(s.entries) - 1 - startChildren
+
 	// Reinitialize the state for this stage of wrapping.
 	s.wantDetail = withDetail
 	s.needSpace = false
@@ -354,11 +401,11 @@ func (s *state) formatRecursive(err error, isOutermost, withDetail bool) {
 		bufIsRedactable = true
 		desiredShortening := v.SafeFormatError((*safePrinter)(s))
 		if desiredShortening == nil {
-			// The error wants to elide the short messages from inner
-			// causes. Do it.
-			for i := range s.entries {
-				s.entries[i].elideShort = true
-			}
+			// The error wants to elide the short messages from inner causes.
+			// Read backwards through list of entries up to the number of new
+			// entries created "under" this one amount and mark `elideShort`
+			// true.
+			s.elideShortChildren(numChildren)
 		}
 
 	case Formatter:
@@ -366,9 +413,7 @@ func (s *state) formatRecursive(err error, isOutermost, withDetail bool) {
 		if desiredShortening == nil {
 			// The error wants to elide the short messages from inner
 			// causes. Do it.
-			for i := range s.entries {
-				s.entries[i].elideShort = true
-			}
+			s.elideShortChildren(numChildren)
 		}
 
 	case fmt.Formatter:
@@ -389,7 +434,11 @@ func (s *state) formatRecursive(err error, isOutermost, withDetail bool) {
 				s.lastStack = st.StackTrace()
 			}
 		} else {
-			s.formatSimple(err, cause)
+			if elideCauseMsg := s.formatSimple(err, cause); elideCauseMsg {
+				// The error wants to elide the short messages from inner
+				// causes. Do it.
+				s.elideShortChildren(numChildren)
+			}
 		}
 
 	default:
@@ -411,9 +460,7 @@ func (s *state) formatRecursive(err error, isOutermost, withDetail bool) {
 				if desiredShortening == nil {
 					// The error wants to elide the short messages from inner
 					// causes. Do it.
-					for i := range s.entries {
-						s.entries[i].elideShort = true
-					}
+					s.elideShortChildren(numChildren)
 				}
 				break
 			}
@@ -422,12 +469,21 @@ func (s *state) formatRecursive(err error, isOutermost, withDetail bool) {
 			// If the error did not implement errors.Formatter nor
 			// fmt.Formatter, but it is a wrapper, still attempt best effort:
 			// print what we can at this level.
-			s.formatSimple(err, cause)
+			elideChildren := s.formatSimple(err, cause)
+			// always elideChildren when dealing with multi-cause errors.
+			if len(causes) > 0 {
+				elideChildren = true
+			}
+			if elideChildren {
+				// The error wants to elide the short messages from inner
+				// causes. Do it.
+				s.elideShortChildren(numChildren)
+			}
 		}
 	}
 
 	// Collect the result.
-	entry := s.collectEntry(err, bufIsRedactable)
+	entry := s.collectEntry(err, bufIsRedactable, withDepth, depth)
 
 	// If there's an embedded stack trace, also collect it.
 	// This will get either a stack from pkg/errors, or ours.
@@ -441,9 +497,22 @@ func (s *state) formatRecursive(err error, isOutermost, withDetail bool) {
 	// Remember the entry for later rendering.
 	s.entries = append(s.entries, entry)
 	s.buf = bytes.Buffer{}
+
+	return numChildren + 1
 }
 
-func (s *state) collectEntry(err error, bufIsRedactable bool) formatEntry {
+// elideShortChildren takes a number of entries to set `elideShort` to
+// false. The reason a number of entries is needed is that we may be
+// eliding a subtree of causes in the case of a multi-cause error. In
+// the multi-cause case, we need to know how many of the prior errors
+// in the list of entries is a child of this subtree.
+func (s *state) elideShortChildren(newEntries int) {
+	for i := 0; i < newEntries; i++ {
+		s.entries[len(s.entries)-1-i].elideShort = true
+	}
+}
+
+func (s *state) collectEntry(err error, bufIsRedactable bool, withDepth bool, depth int) formatEntry {
 	entry := formatEntry{err: err}
 	if s.wantDetail {
 		// The buffer has been populated as a result of formatting with
@@ -480,6 +549,10 @@ func (s *state) collectEntry(err error, bufIsRedactable bool) formatEntry {
 		}
 	}
 
+	if withDepth {
+		entry.depth = depth
+	}
+
 	return entry
 }
 
@@ -500,16 +573,23 @@ func RegisterSpecialCasePrinter(fn safeErrorPrinterFn) {
 // formatSimple performs a best effort at extracting the details at a
 // given level of wrapping when the error object does not implement
 // the Formatter interface.
-func (s *state) formatSimple(err, cause error) {
+// Returns true if we want to elide errors from causal chain.
+func (s *state) formatSimple(err, cause error) bool {
 	var pref string
+	elideCauses := false
 	if cause != nil {
-		pref = extractPrefix(err, cause)
+		var messageType MessageType
+		pref, messageType = extractPrefix(err, cause)
+		if messageType == FullMessage {
+			elideCauses = true
+		}
 	} else {
 		pref = err.Error()
 	}
 	if len(pref) > 0 {
 		s.Write([]byte(pref))
 	}
+	return elideCauses
 }
 
 // finishDisplay renders s.finalBuf into s.State.
@@ -568,7 +648,7 @@ type state struct {
 
 	// entries collect the result of formatRecursive(). They are
 	// consumed by formatSingleLineOutput() and formatEntries() to
-	// procude the contents of finalBuf.
+	// produce the contents of finalBuf.
 	entries []formatEntry
 
 	// buf collects the details of the current error object at a given
@@ -690,6 +770,11 @@ type formatEntry struct {
 	// truncated to avoid duplication of entries. This is used to
 	// display a truncation indicator during verbose rendering.
 	elidedStackTrace bool
+
+	// depth, if positive, represents a nesting depth of this error as
+	// a causer of others. This is used with verbose printing to
+	// illustrate the nesting depth for multi-cause error wrappers.
+	depth int
 }
 
 // String is used for debugging only.
@@ -711,6 +796,12 @@ func (s *state) Write(b []byte) (n int, err error) {
 
 	for i, c := range b {
 		if c == '\n' {
+			//if s.needNewline > 0 {
+			//	for i := 0; i < s.needNewline-1; i++ {
+			//		s.buf.Write(detailSep[:len(sep)-1])
+			//	}
+			//	s.needNewline = 0
+			//}
 			// Flush all the bytes seen so far.
 			s.buf.Write(b[k:i])
 			// Don't print the newline itself; instead, prepare the state so
@@ -740,6 +831,11 @@ func (s *state) Write(b []byte) (n int, err error) {
 			s.notEmpty = true
 		}
 	}
+	//if s.needNewline > 0 {
+	//	for i := 0; i < s.needNewline-1; i++ {
+	//		s.buf.Write(detailSep[:len(sep)-1])
+	//	}
+	//}
 	s.buf.Write(b[k:])
 	return len(b), nil
 }
@@ -766,6 +862,9 @@ func (p *state) switchOver() {
 	p.buf = bytes.Buffer{}
 	p.notEmpty = false
 	p.hasDetail = true
+
+	// One of the newlines is accounted for in the switch over.
+	// p.needNewline -= 1
 }
 
 func (s *printer) Detail() bool {
@@ -829,7 +928,7 @@ func (s *safePrinter) enhanceArgs(args []interface{}) {
 			args[i] = redact.Safe(thisStack)
 			lastSeen = st
 		}
-		// In contrast with (*printer).enhanceArgs(), we dont use a
+		// In contrast with (*printer).enhanceArgs(), we don't use a
 		// special case for `error` here, because the redact package
 		// already helps us recursing into a safe print for
 		// error objects.

vendor/github.com/cockroachdb/errors/errbase/format_simple.go

@@ -1,36 +0,0 @@
-// Copyright 2019 The Cockroach Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-// implied. See the License for the specific language governing
-// permissions and limitations under the License.
-
-package errbase
-
-import "io"
-
-// formatSimpleError is a helper used by FormatError() for the top
-// level error/wrapper argument, if it does not implement the
-// errors.Formatter interface.
-func formatSimpleError(err error, p *state, sep string) error {
-	if cause := UnwrapOnce(err); cause != nil {
-		pref := extractPrefix(err, cause)
-		p.buf.WriteString(pref)
-		if pref != "" {
-			p.buf.WriteByte(':')
-			p.buf.WriteString(sep)
-		}
-		err = cause
-	} else {
-		io.WriteString(&p.buf, err.Error())
-		err = nil
-	}
-	return err
-}

vendor/github.com/cockroachdb/errors/errbase/opaque.go

@@ -30,19 +30,39 @@ type opaqueLeaf struct {
 	details errorspb.EncodedErrorDetails
 }
 
+// opaqueLeafCauses is used when receiving an unknown multi-cause
+// wrapper type. Its important property is that if it is communicated
+// back to some network system that _does_ know about the type, the
+// original object can be restored. We encode multi-cause errors as
+// leaf nodes over the network, in order to support backwards
+// compatibility with existing single-cause wrapper messages.
+//
+// This struct *must* be initialized with a non-nil causes value in
+// order to comply with go stdlib expectations for `Unwrap()`.
+type opaqueLeafCauses struct {
+	opaqueLeaf
+	causes []error
+}
+
 var _ error = (*opaqueLeaf)(nil)
 var _ SafeDetailer = (*opaqueLeaf)(nil)
 var _ fmt.Formatter = (*opaqueLeaf)(nil)
 var _ SafeFormatter = (*opaqueLeaf)(nil)
 
+var _ error = (*opaqueLeafCauses)(nil)
+var _ SafeDetailer = (*opaqueLeafCauses)(nil)
+var _ fmt.Formatter = (*opaqueLeafCauses)(nil)
+var _ SafeFormatter = (*opaqueLeafCauses)(nil)
+
 // opaqueWrapper is used when receiving an unknown wrapper type.
 // Its important property is that if it is communicated
 // back to some network system that _does_ know about
 // the type, the original object can be restored.
 type opaqueWrapper struct {
-	cause   error
-	prefix  string
-	details errorspb.EncodedErrorDetails
+	cause       error
+	prefix      string
+	details     errorspb.EncodedErrorDetails
+	messageType MessageType
 }
 
 var _ error = (*opaqueWrapper)(nil)
@@ -53,6 +73,9 @@ var _ SafeFormatter = (*opaqueWrapper)(nil)
 func (e *opaqueLeaf) Error() string { return e.msg }
 
 func (e *opaqueWrapper) Error() string {
+	if e.messageType == FullMessage {
+		return e.prefix
+	}
 	if e.prefix == "" {
 		return e.cause.Error()
 	}
@@ -66,8 +89,12 @@ func (e *opaqueWrapper) Unwrap() error { return e.cause }
 func (e *opaqueLeaf) SafeDetails() []string    { return e.details.ReportablePayload }
 func (e *opaqueWrapper) SafeDetails() []string { return e.details.ReportablePayload }
 
-func (e *opaqueLeaf) Format(s fmt.State, verb rune)    { FormatError(e, s, verb) }
-func (e *opaqueWrapper) Format(s fmt.State, verb rune) { FormatError(e, s, verb) }
+func (e *opaqueLeaf) Format(s fmt.State, verb rune)       { FormatError(e, s, verb) }
+func (e *opaqueLeafCauses) Format(s fmt.State, verb rune) { FormatError(e, s, verb) }
+func (e *opaqueWrapper) Format(s fmt.State, verb rune)    { FormatError(e, s, verb) }
+
+// opaqueLeafCauses is a multi-cause wrapper
+func (e *opaqueLeafCauses) Unwrap() []error { return e.causes }
 
 func (e *opaqueLeaf) SafeFormatError(p Printer) (next error) {
 	p.Print(e.msg)
@@ -103,5 +130,8 @@ func (e *opaqueWrapper) SafeFormatError(p Printer) (next error) {
 			p.Printf("\npayload type: %s", redact.Safe(e.details.FullDetails.TypeUrl))
 		}
 	}
+	if e.messageType == FullMessage {
+		return nil
+	}
 	return e.cause
 }

vendor/github.com/cockroachdb/errors/errbase/unwrap.go

@@ -27,6 +27,16 @@ package errbase
 // It supports both errors implementing causer (`Cause()` method, from
 // github.com/pkg/errors) and `Wrapper` (`Unwrap()` method, from the
 // Go 2 error proposal).
+//
+// UnwrapOnce treats multi-errors (those implementing the
+// `Unwrap() []error` interface as leaf-nodes since they cannot
+// reasonably be iterated through to a single cause. These errors
+// are typically constructed as a result of `fmt.Errorf` which results
+// in a `wrapErrors` instance that contains an interpolated error
+// string along with a list of causes.
+//
+// The go stdlib does not define output on `Unwrap()` for a multi-cause
+// error, so we default to nil here.
 func UnwrapOnce(err error) (cause error) {
 	switch e := err.(type) {
 	case interface{ Cause() error }:
@@ -39,6 +49,7 @@ func UnwrapOnce(err error) (cause error) {
 
 // UnwrapAll accesses the root cause object of the error.
 // If the error has no cause (leaf error), it is returned directly.
+// UnwrapAll treats multi-errors as leaf nodes.
 func UnwrapAll(err error) error {
 	for {
 		if cause := UnwrapOnce(err); cause != nil {
@@ -49,3 +60,12 @@ func UnwrapAll(err error) error {
 	}
 	return err
 }
+
+// UnwrapMulti access the slice of causes that an error contains, if it is a
+// multi-error.
+func UnwrapMulti(err error) []error {
+	if me, ok := err.(interface{ Unwrap() []error }); ok {
+		return me.Unwrap()
+	}
+	return nil
+}