[bugfix] return 400 Bad Request on more cases of malformed AS data (#2399)

vendor/codeberg.org/gruf/go-errors/v2/README.md

@@ -1,5 +1,8 @@
 # go-errors
 
-simple but powerful errors library that allows easy wrapping and stacktracing of errors.
-
-to disable stacktraces set the `notrace` build tag.
+powerful errors library with a simple API that allows:
+- accessing all the standard library errors functions
+- wrapping of errors
+- adding values to errors, in a similar manner to contexts
+- including calling function prefix when tag=errcaller is set
+- including stacktrace with error when tag=errtrace is set

vendor/codeberg.org/gruf/go-errors/v2/build_caller.go

@@ -0,0 +1,26 @@
+//go:build errcaller
+// +build errcaller
+
+package errors
+
+import (
+	_ "unsafe"
+)
+
+// IncludesCaller is a compile-time flag used to indicate whether
+// to include calling function prefix on error wrap / creation.
+const IncludesCaller = true
+
+type caller string
+
+// set will set the actual caller value
+// only when correct build flag is set.
+func (c *caller) set(v string) {
+	*c = caller(v)
+}
+
+// value returns the actual caller value
+// only when correct build flag is set
+func (c caller) value() string {
+	return string(c)
+}

vendor/codeberg.org/gruf/go-errors/v2/build_nocaller.go

@@ -0,0 +1,18 @@
+//go:build !errcaller
+// +build !errcaller
+
+package errors
+
+// IncludesCaller is a compile-time flag used to indicate whether
+// to include calling function prefix on error wrap / creation.
+const IncludesCaller = false
+
+type caller struct{}
+
+// set will set the actual caller value
+// only when correct build flag is set.
+func (caller) set(string) {}
+
+// value returns the actual caller value
+// only when correct build flag is set.
+func (caller) value() string { return "" }

vendor/codeberg.org/gruf/go-errors/v2/build_notrace.go

@@ -0,0 +1,20 @@
+//go:build !errtrace
+// +build !errtrace
+
+package errors
+
+import "runtime"
+
+// IncludesStacktrace is a compile-time flag used to indicate
+// whether to include stacktraces on error wrap / creation.
+const IncludesStacktrace = false
+
+type trace struct{}
+
+// set will set the actual trace value
+// only when correct build flag is set.
+func (trace) set([]runtime.Frame) {}
+
+// value returns the actual trace value
+// only when correct build flag is set.
+func (trace) value() Callers { return nil }

vendor/codeberg.org/gruf/go-errors/v2/build_trace.go

@@ -0,0 +1,27 @@
+//go:build errtrace
+// +build errtrace
+
+package errors
+
+import (
+	"runtime"
+	_ "unsafe"
+)
+
+// IncludesStacktrace is a compile-time flag used to indicate
+// whether to include stacktraces on error wrap / creation.
+const IncludesStacktrace = true
+
+type trace []runtime.Frame
+
+// set will set the actual trace value
+// only when correct build flag is set.
+func (t *trace) set(v []runtime.Frame) {
+	*t = trace(v)
+}
+
+// value returns the actual trace value
+// only when correct build flag is set.
+func (t trace) value() Callers {
+	return Callers(t)
+}

vendor/codeberg.org/gruf/go-errors/v2/callers.go

@@ -1,98 +0,0 @@
-package errors
-
-import (
-	"encoding/json"
-	"runtime"
-	"strconv"
-	"strings"
-	"unsafe"
-)
-
-// Callers is a stacktrace of caller PCs.
-type Callers []uintptr
-
-// GetCallers returns a Callers slice of PCs, of at most 'depth'.
-func GetCallers(skip int, depth int) Callers {
-	rpc := make([]uintptr, depth)
-	n := runtime.Callers(skip+1, rpc)
-	return Callers(rpc[0:n])
-}
-
-// Frames fetches runtime frames for a slice of caller PCs.
-func (f Callers) Frames() []runtime.Frame {
-	// Allocate expected frames slice
-	frames := make([]runtime.Frame, 0, len(f))
-
-	// Get frames iterator for PCs
-	iter := runtime.CallersFrames(f)
-
-	for {
-		// Get next frame in iter
-		frame, ok := iter.Next()
-		if !ok {
-			break
-		}
-
-		// Append to frames slice
-		frames = append(frames, frame)
-	}
-
-	return frames
-}
-
-// MarshalJSON implements json.Marshaler to provide an easy, simple default.
-func (f Callers) MarshalJSON() ([]byte, error) {
-	// JSON-able frame type
-	type jsonFrame struct {
-		Func string `json:"func"`
-		File string `json:"file"`
-		Line int    `json:"line"`
-	}
-
-	// Convert to frames
-	frames := f.Frames()
-
-	// Allocate expected size jsonFrame slice
-	jsonFrames := make([]jsonFrame, 0, len(f))
-
-	for i := 0; i < len(frames); i++ {
-		frame := frames[i]
-
-		// Convert each to jsonFrame object
-		jsonFrames = append(jsonFrames, jsonFrame{
-			Func: funcname(frame.Function),
-			File: frame.File,
-			Line: frame.Line,
-		})
-	}
-
-	// marshal converted frames
-	return json.Marshal(frames)
-}
-
-// String will return a simple string representation of receiving Callers slice.
-func (f Callers) String() string {
-	// Guess-timate to reduce allocs
-	buf := make([]byte, 0, 64*len(f))
-
-	// Convert to frames
-	frames := f.Frames()
-
-	for i := 0; i < len(frames); i++ {
-		frame := frames[i]
-
-		// Append formatted caller info
-		fn := funcname(frame.Function)
-		buf = append(buf, fn+"()\n\t"+frame.File+":"...)
-		buf = strconv.AppendInt(buf, int64(frame.Line), 10)
-		buf = append(buf, '\n')
-	}
-
-	return *(*string)(unsafe.Pointer(&buf))
-}
-
-// funcname splits a function name with pkg from its path prefix.
-func funcname(name string) string {
-	i := strings.LastIndex(name, "/")
-	return name[i+1:]
-}

vendor/codeberg.org/gruf/go-errors/v2/error.go

@@ -1,35 +0,0 @@
-//go:build !notrace
-// +build !notrace
-
-package errors
-
-type errormsg struct {
-	msg   string
-	wrap  error
-	stack Callers
-}
-
-func create(msg string, wrap error) *errormsg {
-	return &errormsg{
-		msg:   msg,
-		wrap:  wrap,
-		stack: GetCallers(2, 10),
-	}
-}
-
-func (err *errormsg) Error() string {
-	return err.msg
-}
-
-func (err *errormsg) Is(target error) bool {
-	other, ok := target.(*errormsg)
-	return ok && (err.msg == other.msg)
-}
-
-func (err *errormsg) Unwrap() error {
-	return err.wrap
-}
-
-func (err *errormsg) Stacktrace() Callers {
-	return err.stack
-}

vendor/codeberg.org/gruf/go-errors/v2/error_notrace.go

@@ -1,33 +0,0 @@
-//go:build notrace
-// +build notrace
-
-package errors
-
-type errormsg struct {
-	msg  string
-	wrap error
-}
-
-func create(msg string, wrap error) *errormsg {
-	return &errormsg{
-		msg:  msg,
-		wrap: wrap,
-	}
-}
-
-func (err *errormsg) Error() string {
-	return err.msg
-}
-
-func (err *errormsg) Is(target error) bool {
-	other, ok := target.(*errormsg)
-	return ok && (err.msg == other.msg)
-}
-
-func (err *errormsg) Unwrap() error {
-	return err.wrap
-}
-
-func (err *errormsg) Stacktrace() Callers {
-	return nil
-}

vendor/codeberg.org/gruf/go-errors/v2/errors.go

@@ -1,37 +1,248 @@
 package errors
 
 import (
-	"errors"
 	"fmt"
+	"runtime"
 )
 
 // New returns a new error created from message.
+//
+// Note this function cannot be inlined, to ensure expected
+// and consistent behaviour in setting trace / caller info.
+//
+//go:noinline
 func New(msg string) error {
-	return create(msg, nil)
+	var c caller
+	var t trace
+	if IncludesCaller {
+		pcs := make([]uintptr, 1)
+		_ = runtime.Callers(2, pcs)
+		fn := runtime.FuncForPC(pcs[0])
+		c.set(funcName(fn))
+	}
+	if IncludesStacktrace {
+		pcs := make([]uintptr, 10)
+		n := runtime.Callers(2, pcs)
+		iter := runtime.CallersFrames(pcs[:n])
+		t.set(gatherFrames(iter, n))
+	}
+	return &_errormsg{
+		cfn: c,
+		msg: msg,
+		trc: t,
+	}
 }
 
 // Newf returns a new error created from message format and args.
+//
+// Note this function cannot be inlined, to ensure expected
+// and consistent behaviour in setting trace / caller info.
+//
+//go:noinline
 func Newf(msgf string, args ...interface{}) error {
-	return create(fmt.Sprintf(msgf, args...), nil)
+	var c caller
+	var t trace
+	if IncludesCaller {
+		pcs := make([]uintptr, 1)
+		_ = runtime.Callers(2, pcs)
+		fn := runtime.FuncForPC(pcs[0])
+		c.set(funcName(fn))
+	}
+	if IncludesStacktrace {
+		pcs := make([]uintptr, 10)
+		n := runtime.Callers(2, pcs)
+		iter := runtime.CallersFrames(pcs[:n])
+		t.set(gatherFrames(iter, n))
+	}
+	return &_errormsg{
+		cfn: c,
+		msg: fmt.Sprintf(msgf, args...),
+		trc: t,
+	}
+}
+
+// NewAt returns a new error created, skipping 'skip'
+// frames for trace / caller information, from message.
+//
+// Note this function cannot be inlined, to ensure expected
+// and consistent behaviour in setting trace / caller info.
+//
+//go:noinline
+func NewAt(skip int, msg string) error {
+	var c caller
+	var t trace
+	if IncludesCaller {
+		pcs := make([]uintptr, 1)
+		_ = runtime.Callers(skip+1, pcs)
+		fn := runtime.FuncForPC(pcs[0])
+		c.set(funcName(fn))
+	}
+	if IncludesStacktrace {
+		pcs := make([]uintptr, 10)
+		n := runtime.Callers(skip+1, pcs)
+		iter := runtime.CallersFrames(pcs[:n])
+		t.set(gatherFrames(iter, n))
+	}
+	return &_errormsg{
+		cfn: c,
+		msg: msg,
+		trc: t,
+	}
 }
 
 // Wrap will wrap supplied error within a new error created from message.
+//
+// Note this function cannot be inlined, to ensure expected
+// and consistent behaviour in setting trace / caller info.
+//
+//go:noinline
 func Wrap(err error, msg string) error {
-	return create(msg, err)
+	if err == nil {
+		panic("cannot wrap nil error")
+	}
+	var c caller
+	var t trace
+	if IncludesCaller {
+		pcs := make([]uintptr, 1)
+		_ = runtime.Callers(2, pcs)
+		fn := runtime.FuncForPC(pcs[0])
+		c.set(funcName(fn))
+	}
+	if IncludesStacktrace {
+		pcs := make([]uintptr, 10)
+		n := runtime.Callers(2, pcs)
+		iter := runtime.CallersFrames(pcs[:n])
+		t.set(gatherFrames(iter, n))
+	}
+	return &_errorwrap{
+		cfn: c,
+		msg: msg,
+		err: err,
+		trc: t,
+	}
 }
 
 // Wrapf will wrap supplied error within a new error created from message format and args.
+//
+// Note this function cannot be inlined, to ensure expected
+// and consistent behaviour in setting trace / caller info.
+//
+//go:noinline
 func Wrapf(err error, msgf string, args ...interface{}) error {
-	return create(fmt.Sprintf(msgf, args...), err)
+	if err == nil {
+		panic("cannot wrap nil error")
+	}
+	var c caller
+	var t trace
+	if IncludesCaller {
+		pcs := make([]uintptr, 1)
+		_ = runtime.Callers(2, pcs)
+		fn := runtime.FuncForPC(pcs[0])
+		c.set(funcName(fn))
+	}
+	if IncludesStacktrace {
+		pcs := make([]uintptr, 10)
+		n := runtime.Callers(2, pcs)
+		iter := runtime.CallersFrames(pcs[:n])
+		t.set(gatherFrames(iter, n))
+	}
+	return &_errorwrap{
+		cfn: c,
+		msg: fmt.Sprintf(msgf, args...),
+		err: err,
+		trc: t,
+	}
+}
+
+// WrapAt wraps error within new error created from message,
+// skipping 'skip' frames for trace / caller information.
+//
+// Note this function cannot be inlined, to ensure expected
+// and consistent behaviour in setting trace / caller info.
+//
+//go:noinline
+func WrapAt(skip int, err error, msg string) error {
+	if err == nil {
+		panic("cannot wrap nil error")
+	}
+	var c caller
+	var t trace
+	if IncludesCaller {
+		pcs := make([]uintptr, 1)
+		_ = runtime.Callers(skip+1, pcs)
+		fn := runtime.FuncForPC(pcs[0])
+		c.set(funcName(fn))
+	}
+	if IncludesStacktrace {
+		pcs := make([]uintptr, 10)
+		n := runtime.Callers(skip+1, pcs)
+		iter := runtime.CallersFrames(pcs[:n])
+		t.set(gatherFrames(iter, n))
+	}
+	return &_errorwrap{
+		cfn: c,
+		msg: msg,
+		err: err,
+		trc: t,
+	}
 }
 
 // Stacktrace fetches first stored stacktrace of callers from error chain.
 func Stacktrace(err error) Callers {
-	var e interface {
-		Stacktrace() Callers
-	}
-	if !errors.As(err, &e) {
+	if !IncludesStacktrace {
+		// compile-time check
 		return nil
 	}
-	return e.Stacktrace()
+	if e := AsV2[*_errormsg](err); err != nil {
+		return e.trc.value()
+	}
+	if e := AsV2[*_errorwrap](err); err != nil {
+		return e.trc.value()
+	}
+	return nil
+}
+
+type _errormsg struct {
+	cfn caller
+	msg string
+	trc trace
+}
+
+func (err *_errormsg) Error() string {
+	if IncludesCaller {
+		fn := err.cfn.value()
+		return fn + " " + err.msg
+	} else {
+		return err.msg
+	}
+}
+
+func (err *_errormsg) Is(other error) bool {
+	oerr, ok := other.(*_errormsg)
+	return ok && oerr.msg == err.msg
+}
+
+type _errorwrap struct {
+	cfn caller
+	msg string
+	err error // wrapped
+	trc trace
+}
+
+func (err *_errorwrap) Error() string {
+	if IncludesCaller {
+		fn := err.cfn.value()
+		return fn + " " + err.msg + ": " + err.err.Error()
+	} else {
+		return err.msg + ": " + err.err.Error()
+	}
+}
+
+func (err *_errorwrap) Is(other error) bool {
+	oerr, ok := other.(*_errorwrap)
+	return ok && oerr.msg == err.msg
+}
+
+func (err *_errorwrap) Unwrap() error {
+	return err.err
 }

vendor/codeberg.org/gruf/go-errors/v2/once.go

@@ -2,46 +2,30 @@ package errors
 
 import (
 	"sync/atomic"
-	"unsafe"
 )
 
 // OnceError is an error structure that supports safe multi
 // threaded usage and setting only once (until reset).
-type OnceError struct{ err unsafe.Pointer }
-
-// NewOnce returns a new OnceError instance.
-func NewOnce() OnceError {
-	return OnceError{
-		err: nil,
-	}
-}
+type OnceError struct{ ptr atomic.Pointer[error] }
 
 // Store will safely set the OnceError to value, no-op if nil.
-func (e *OnceError) Store(err error) {
-	// Nothing to do
+func (e *OnceError) Store(err error) bool {
 	if err == nil {
-		return
+		return false
 	}
-
-	// Only set if not already
-	atomic.CompareAndSwapPointer(
-		&e.err,
-		nil,
-		unsafe.Pointer(&err),
-	)
+	return e.ptr.CompareAndSwap(nil, &err)
 }
 
 // Load will load the currently stored error.
 func (e *OnceError) Load() error {
-	return *(*error)(atomic.LoadPointer(&e.err))
+	if ptr := e.ptr.Load(); ptr != nil {
+		return *ptr
+	}
+	return nil
 }
 
 // IsSet returns whether OnceError has been set.
-func (e *OnceError) IsSet() bool {
-	return (atomic.LoadPointer(&e.err) != nil)
-}
+func (e *OnceError) IsSet() bool { return (e.ptr.Load() != nil) }
 
 // Reset will reset the OnceError value.
-func (e *OnceError) Reset() {
-	atomic.StorePointer(&e.err, nil)
-}
+func (e *OnceError) Reset() { e.ptr.Store(nil) }

vendor/codeberg.org/gruf/go-errors/v2/runtime.go

@@ -0,0 +1,97 @@
+package errors
+
+import (
+	"encoding/json"
+	"runtime"
+	"strconv"
+	"strings"
+	"unsafe"
+)
+
+// Callers ...
+type Callers []runtime.Frame
+
+// MarshalJSON implements json.Marshaler to provide an easy, simple default.
+func (c Callers) MarshalJSON() ([]byte, error) {
+	// JSON-able frame type
+	type jsonFrame struct {
+		Func string `json:"func"`
+		File string `json:"file"`
+		Line int    `json:"line"`
+	}
+
+	// Allocate expected size jsonFrame slice
+	jsonFrames := make([]jsonFrame, len(c))
+
+	// Convert each to jsonFrame object
+	for i := 0; i < len(c); i++ {
+		frame := c[i]
+		jsonFrames[i] = jsonFrame{
+			Func: funcName(frame.Func),
+			File: frame.File,
+			Line: frame.Line,
+		}
+	}
+
+	// marshal converted frames
+	return json.Marshal(jsonFrames)
+}
+
+// String will return a simple string representation of receiving Callers slice.
+func (c Callers) String() string {
+	// Guess-timate to reduce allocs
+	buf := make([]byte, 0, 64*len(c))
+
+	for i := 0; i < len(c); i++ {
+		frame := c[i]
+
+		// Append formatted caller info
+		fn := funcName(frame.Func)
+		buf = append(buf, fn+"()\n\t"+frame.File+":"...)
+		buf = strconv.AppendInt(buf, int64(frame.Line), 10)
+		buf = append(buf, '\n')
+	}
+
+	return *(*string)(unsafe.Pointer(&buf))
+}
+
+// funcName formats a function name to a quickly-readable string.
+func funcName(fn *runtime.Func) string {
+	if fn == nil {
+		return ""
+	}
+
+	// Get func name
+	// for formatting.
+	name := fn.Name()
+
+	// Drop all but the package name and function name, no mod path
+	if idx := strings.LastIndex(name, "/"); idx >= 0 {
+		name = name[idx+1:]
+	}
+
+	const params = `[...]`
+
+	// Drop any generic type parameter markers
+	if idx := strings.Index(name, params); idx >= 0 {
+		name = name[:idx] + name[idx+len(params):]
+	}
+
+	return name
+}
+
+// gatherFrames collates runtime frames from a frame iterator.
+func gatherFrames(iter *runtime.Frames, n int) Callers {
+	if iter == nil {
+		return nil
+	}
+	frames := make([]runtime.Frame, 0, n)
+	for {
+		f, ok := iter.Next()
+		if !ok {
+			break
+		}
+		frames = append(frames, f)
+	}
+	return frames
+}

vendor/codeberg.org/gruf/go-errors/v2/standard.go

@@ -1,133 +1,37 @@
 package errors
 
 import (
-	"errors"
-	"reflect"
 	_ "unsafe"
-
-	"codeberg.org/gruf/go-bitutil"
 )
 
-// errtype is a ptr to the error interface type.
-var errtype = reflect.TypeOf((*error)(nil)).Elem()
+// Is reports whether any error in err's tree matches target.
+//
+// The tree consists of err itself, followed by the errors obtained by repeatedly
+// calling Unwrap. When err wraps multiple errors, Is examines err followed by a
+// depth-first traversal of its children.
+//
+// An error is considered to match a target if it is equal to that target or if
+// it implements a method Is(error) bool such that Is(target) returns true.
+//
+// An error type might provide an Is method so it can be treated as equivalent
+// to an existing error. For example, if MyError defines
+//
+//	func (m MyError) Is(target error) bool { return target == fs.ErrExist }
+//
+// then Is(MyError{}, fs.ErrExist) returns true. See [syscall.Errno.Is] for
+// an example in the standard library. An Is method should only shallowly
+// compare err and the target and not call Unwrap on either.
+//
+//go:linkname Is errors.Is
+func Is(err error, target error) bool
 
-// Comparable is functionally equivalent to calling errors.Is() on multiple errors (up to a max of 64).
-func Comparable(err error, targets ...error) bool {
-	var flags bitutil.Flags64
-
-	// Flags only has 64 bit-slots
-	if len(targets) > 64 {
-		panic("too many targets")
-	}
-
-	for i := 0; i < len(targets); {
-		if targets[i] == nil {
-			if err == nil {
-				return true
-			}
-
-			// Drop nil targets from slice.
-			copy(targets[i:], targets[i+1:])
-			targets = targets[:len(targets)-1]
-			continue
+// IsV2 calls Is(err, target) for each target within targets.
+func IsV2(err error, targets ...error) bool {
+	for _, target := range targets {
+		if Is(err, target) {
+			return true
 		}
-
-		// Check if this error is directly comparable
-		if reflect.TypeOf(targets[i]).Comparable() {
-			flags = flags.Set(uint8(i))
-		}
-
-		i++
 	}
-
-	for err != nil {
-		// Check if this layer supports .Is interface
-		is, ok := err.(interface{ Is(error) bool })
-
-		if !ok {
-			// Error does not support interface
-			//
-			// Only try perform direct compare
-			for i := 0; i < len(targets); i++ {
-				// Try directly compare errors
-				if flags.Get(uint8(i)) &&
-					err == targets[i] {
-					return true
-				}
-			}
-		} else {
-			// Error supports the .Is interface
-			//
-			// Perform direct compare AND .Is()
-			for i := 0; i < len(targets); i++ {
-				if (flags.Get(uint8(i)) &&
-					err == targets[i]) ||
-					is.Is(targets[i]) {
-					return true
-				}
-			}
-		}
-
-		// Unwrap to next layer
-		err = errors.Unwrap(err)
-	}
-
-	return false
-}
-
-// Assignable is functionally equivalent to calling errors.As() on multiple errors,
-// except that it only checks assignability as opposed to setting the target.
-func Assignable(err error, targets ...error) bool {
-	if err == nil {
-		// Fastest case.
-		return false
-	}
-
-	for i := 0; i < len(targets); {
-		if targets[i] == nil {
-			// Drop nil targets from slice.
-			copy(targets[i:], targets[i+1:])
-			targets = targets[:len(targets)-1]
-			continue
-		}
-		i++
-	}
-
-	for err != nil {
-		// Check if this layer supports .As interface
-		as, ok := err.(interface{ As(any) bool })
-
-		// Get reflected err type.
-		te := reflect.TypeOf(err)
-
-		if !ok {
-			// Error does not support interface.
-			//
-			// Check assignability using reflection.
-			for i := 0; i < len(targets); i++ {
-				tt := reflect.TypeOf(targets[i])
-				if te.AssignableTo(tt) {
-					return true
-				}
-			}
-		} else {
-			// Error supports the .As interface.
-			//
-			// Check using .As() and reflection.
-			for i := 0; i < len(targets); i++ {
-				if as.As(targets[i]) {
-					return true
-				} else if tt := reflect.TypeOf(targets[i]); // nocollapse
-				te.AssignableTo(tt) {
-					return true
-				}
-			}
-		}
-
-		// Unwrap to next layer.
-		err = errors.Unwrap(err)
-	}
-
 	return false
 }
 
@@ -152,8 +56,79 @@ func Assignable(err error, targets ...error) bool {
 //go:linkname As errors.As
 func As(err error, target any) bool
 
+// AsV2 is functionally similar to As(), instead
+// leveraging generics to handle allocation and
+// returning of a concrete generic parameter type.
+func AsV2[Type any](err error) Type {
+	var t Type
+	var ok bool
+	errs := []error{err}
+	for len(errs) > 0 {
+		// Pop next error to check.
+		err := errs[len(errs)-1]
+		errs = errs[:len(errs)-1]
+
+		// Check direct type.
+		t, ok = err.(Type)
+		if ok {
+			return t
+		}
+
+		// Look for .As() support.
+		as, ok := err.(interface {
+			As(target any) bool
+		})
+
+		if ok {
+			// Attempt .As().
+			if as.As(&t) {
+				return t
+			}
+		}
+
+		// Try unwrap errors.
+		switch u := err.(type) {
+		case interface{ Unwrap() error }:
+			errs = append(errs, u.Unwrap())
+		case interface{ Unwrap() []error }:
+			errs = append(errs, u.Unwrap()...)
+		}
+	}
+	return t
+}
+
 // Unwrap returns the result of calling the Unwrap method on err, if err's
-// type contains an Unwrap method returning error. Otherwise, Unwrap returns nil.
+// type contains an Unwrap method returning error.
+// Otherwise, Unwrap returns nil.
+//
+// Unwrap only calls a method of the form "Unwrap() error".
+// In particular Unwrap does not unwrap errors returned by [Join].
 //
 //go:linkname Unwrap errors.Unwrap
 func Unwrap(err error) error
+
+// UnwrapV2 is functionally similar to Unwrap(), except that
+// it also handles the case of interface{ Unwrap() []error }.
+func UnwrapV2(err error) []error {
+	switch u := err.(type) {
+	case interface{ Unwrap() error }:
+		if e := u.Unwrap(); err != nil {
+			return []error{e}
+		}
+	case interface{ Unwrap() []error }:
+		return u.Unwrap()
+	}
+	return nil
+}
+
+// Join returns an error that wraps the given errors.
+// Any nil error values are discarded.
+// Join returns nil if every value in errs is nil.
+// The error formats as the concatenation of the strings obtained
+// by calling the Error method of each element of errs, with a newline
+// between each string.
+//
+// A non-nil error returned by Join implements the Unwrap() []error method.
+//
+//go:linkname Join errors.Join
+func Join(errs ...error) error

vendor/codeberg.org/gruf/go-errors/v2/value.go

@@ -1,56 +1,50 @@
 package errors
 
-import "errors"
-
 // WithValue wraps err to store given key-value pair, accessible via Value() function.
 func WithValue(err error, key any, value any) error {
 	if err == nil {
 		panic("nil error")
 	}
-	return &errWithValue{
+	var kvs []kv
+	if e := AsV2[*errWithValues](err); e != nil {
+		kvs = e.kvs
+	}
+	return &errWithValues{
 		err: err,
-		key: key,
-		val: value,
+		kvs: append(kvs, kv{key, value}),
 	}
 }
 
 // Value searches for value stored under given key in error chain.
 func Value(err error, key any) any {
-	var e *errWithValue
-
-	if !errors.As(err, &e) {
-		return nil
+	if e := AsV2[*errWithValues](err); e != nil {
+		return e.Value(key)
 	}
-
-	return e.Value(key)
+	return nil
 }
 
-type errWithValue struct {
+// simple key-value type.
+type kv struct{ k, v any }
+
+// errWithValues wraps an error to provide key-value storage.
+type errWithValues struct {
 	err error
-	key any
-	val any
+	kvs []kv
 }
 
-func (e *errWithValue) Error() string {
+func (e *errWithValues) Error() string {
 	return e.err.Error()
 }
 
-func (e *errWithValue) Is(target error) bool {
-	return e.err == target
+func (e *errWithValues) Unwrap() error {
+	return e.err
 }
 
-func (e *errWithValue) Unwrap() error {
-	return Unwrap(e.err)
-}
-
-func (e *errWithValue) Value(key any) any {
-	for {
-		if key == e.key {
-			return e.val
-		}
-
-		if !errors.As(e.err, &e) {
-			return nil
+func (e *errWithValues) Value(key any) any {
+	for i := range e.kvs {
+		if e.kvs[i].k == key {
+			return e.kvs[i].v
 		}
 	}
+	return nil
 }