zerr: sequence: changed into interface for future proofing

core/zerr/err.go

@@ -27,7 +27,7 @@ type Err struct {
 	id            string
 	logger        Logger
 	notifier      Notifier
-	sequence      *Sequence
+	sequence      Sequence
 }
 
 // Join implements Error.
@@ -215,7 +215,7 @@ func (mu *Err) Notify(ctx context.Context, opts ...zoptions.NotifyOption) Error
 }
 
 // Sequence returns the state of the error sequence.
-func (mu *Err) Sequence() *Sequence {
+func (mu *Err) Sequence() Sequence {
 	return mu.sequence
 }
 

core/zerr/err_write_to.go

@@ -18,9 +18,11 @@ func (er *Err) WriteBuilder(w io.Writer) {
 		return
 	}
 	var previous string
-	if err := er.sequence.Outer(); err != nil && !err.IsMulti() {
+	if parent := er.sequence.Parent(); parent != nil {
+		if err := parent.Error(); err != nil && !err.IsMulti() {
 			previous = err.GetMessage()
 		}
+	}
 	current := strings.TrimPrefix(er.message, previous)
 	if current != "" {
 		if previous != "" {

core/zerr/error.go

@@ -85,7 +85,9 @@ type Error interface {
 	Notify(ctx context.Context, opts ...zoptions.NotifyOption) Error
 
 	// Sequence returns the state of the error sequence.
-	Sequence() *Sequence
+	//
+	// Sequence must not be nil.
+	Sequence() Sequence
 
 	// IsMulti returns true if the error is a multiple error.
 	IsMulti() bool

core/zerr/sequence.go

@@ -9,24 +9,50 @@ import "iter"
 // When wrapping errors, the wrapping error
 // will be the parent of the wrapped Error
 // if the wrapped Error is a zerr.Error.
-type Sequence struct {
-	parent   *Sequence
-	children []*Sequence
+type Sequence interface {
+	// WrapBy prepends the next Sequence to the current Sequence.
+	WrapBy(parent Sequence)
+
+	// Parent returns the parent Sequence.
+	// Return nil if this Sequence is Root.
+	Parent() Sequence
+
+	// Root returns the outermost Sequence in the sequence.
+	//
+	// Returns self if current Sequence is the outermost.
+	Root() Sequence
+
+	// IsRoot checks if the Sequence is the outermost Sequence in the sequence.
+	IsRoot() bool
+
+	// Error returns the Error in the sequence.
+	Error() Error
+
+	// Iter returns an iterator to traverse Errors in the sequence.
+	Iter() iter.Seq[Error]
+
+	// AppendChild appends a child Sequence to the current Sequence.
+	AppendChild(child Sequence)
+}
+
+type sequence struct {
+	parent   Sequence
+	children []Sequence
 	err      Error
 }
 
-// WrapBy prepends the next Sequence to the current Sequence.
-func (se *Sequence) WrapBy(parent *Sequence) {
-	parent.children = append(parent.children, se)
+func (se *sequence) WrapBy(parent Sequence) {
+	parent.AppendChild(se)
 	se.parent = parent
 }
 
-// Outer returns the error that wraps this Error.
-// Return nil if this Error is not wrapped
-// or wrapping outer is not a zerr.Error.
-func (se *Sequence) Outer() Error {
+func (se *sequence) AppendChild(child Sequence) {
+	se.children = append(se.children, child)
+}
+
+func (se *sequence) Parent() Sequence {
 	if se.parent != nil {
-		return se.parent.err
+		return se.parent
 	}
 	return nil
 }
@@ -34,21 +60,23 @@ func (se *Sequence) Outer() Error {
 // Root returns the outermost Error in the sequence.
 //
 // Returns self if there is no outermost.
-func (se *Sequence) Root() *Sequence {
-	root := se
-	for root.parent != nil {
-		root = root.parent
-	}
+func (se *sequence) Root() Sequence {
+	var root Sequence = se
+	for {
+		if root.Parent() == nil {
 			return root
+		}
+		root = root.Parent()
+	}
 }
 
 // IsRoot checks if the Error is the outermost Error in the sequence.
-func (se *Sequence) IsRoot() bool {
+func (se *sequence) IsRoot() bool {
 	return se.parent == nil
 }
 
 // Error returns the Error in the sequence.
-func (se *Sequence) Error() Error {
+func (se *sequence) Error() Error {
 	return se.err
 }
 
@@ -64,7 +92,7 @@ func (se *Sequence) Error() Error {
 //	   // e is zerr.Error
 //	   // do something with e
 //	}
-func (se *Sequence) Iter() iter.Seq[Error] {
+func (se *sequence) Iter() iter.Seq[Error] {
 	return func(yield func(Error) bool) {
 		if se.err != nil && !yield(se.err) {
 			return

core/zerr/wrap.go

@@ -7,19 +7,20 @@ import (
 	"gitlab.bareksa.com/backend/zen/core/zoptions"
 )
 
-type WrapInitialInput struct {
-	Error    error
+type WrapInput struct {
+	Errors   []error
 	Message  string
 	PC       uintptr
 	Time     time.Time
 	Logger   Logger
 	Notifier Notifier
+	Details  []any
 }
 
 type Wrapper interface {
 	// Wrap creates a zerr.Error with inputs
 	// generated by global entry points.
-	Wrap(input WrapInitialInput) Error
+	Wrap(input WrapInput) Error
 }
 
 type Logger interface {
@@ -30,12 +31,35 @@ type Notifier interface {
 	NotifyError(ctx context.Context, err Error, opts ...zoptions.NotifyOption)
 }
 
-type WrapperFunc func(input WrapInitialInput) Error
+type WrapperFunc func(input WrapInput) Error
 
-func (wr WrapperFunc) Wrap(input WrapInitialInput) Error {
+func (wr WrapperFunc) Wrap(input WrapInput) Error {
 	return wr(input)
 }
 
-var DefaultWrapper Wrapper = WrapperFunc(func(input WrapInitialInput) Error {
-	panic("not implemented")
+var DefaultWrapper Wrapper = WrapperFunc(func(input WrapInput) Error {
+	e := &Err{
+		message:  input.Message,
+		errs:     input.Errors,
+		caller:   input.PC,
+		time:     input.Time,
+		logger:   input.Logger,
+		notifier: input.Notifier,
+		details:  input.Details,
+	}
+	e.sequence = &sequence{err: e}
+	for _, err := range input.Errors {
+		if err, ok := err.(Error); ok {
+			err.Sequence().WrapBy(e.sequence)
+		}
+	}
+	return e
 })
+
+func Wrap(input WrapInput) Error {
+	return DefaultWrapper.Wrap(input)
+}
+
+func SetDefaultWrapper(w Wrapper) {
+	DefaultWrapper = w
+}

go.mod

@@ -6,6 +6,8 @@ require (
 	connectrpc.com/connect v1.16.2
 	connectrpc.com/grpcreflect v1.2.0
 	github.com/fatih/color v1.17.0
+	github.com/mattn/go-isatty v0.0.20
+	github.com/pborman/indent v1.2.1
 	github.com/tidwall/pretty v1.2.1
 	golang.org/x/net v0.23.0
 	google.golang.org/protobuf v1.34.2
@@ -13,8 +15,6 @@ require (
 
 require (
 	github.com/mattn/go-colorable v0.1.13 // indirect
-	github.com/mattn/go-isatty v0.0.20 // indirect
-	github.com/pborman/indent v1.2.1 // indirect
 	golang.org/x/sys v0.18.0 // indirect
 	golang.org/x/text v0.14.0 // indirect
 )