AlistGo/alist · warning · NotImplement

not implement

Error message

not implement

What it means

errs.NotImplement marks a driver method that the storage backend deliberately does not provide (as opposed to not-yet-written). When a caller invokes such a method on the driver, this sentinel is returned so upper layers can surface 'this operation is not available' rather than panic or silently no-op.

Source

Thrown at internal/errs/errors.go:11

package errs

import (
	"errors"
	"fmt"

	pkgerr "github.com/pkg/errors"
)

var (
	NotImplement = errors.New("not implement")
	NotSupport   = errors.New("not support")
	RelativePath = errors.New("access using relative path is not allowed")

	MoveBetweenTwoStorages = errors.New("can't move files between two storages, try to copy")
	UploadNotSupported     = errors.New("upload not supported")

	MetaNotFound     = errors.New("meta not found")
	StorageNotFound  = errors.New("storage not found")
	StreamIncomplete = errors.New("upload/download stream incomplete, possible network issue")
	StreamPeekFail   = errors.New("StreamPeekFail")

	UnknownArchiveFormat      = errors.New("unknown archive format")
	WrongArchivePassword      = errors.New("wrong archive password")
	DriverExtractNotSupported = errors.New("driver extraction not supported")
)

// NewErr wrap constant error with an extra message
// use errors.Is(err1, StorageNotFound) to check if err belongs to any internal error

View on GitHub (pinned to 843d9dc814)

Solutions

1. Check the driver's documented capability set before invoking optional operations
2. Guard the call: treat NotImplement as 'feature absent' and hide/disable the corresponding UI action
3. Switch to a driver that supports the operation, or perform the operation out-of-band
4. For driver authors: implement the method or keep returning the sentinel so callers can detect it

Example fix

// before
err := fsRename(ctx, storage, obj, "new.txt")

// after
err := fsRename(ctx, storage, obj, "new.txt")
if errors.Is(err, errs.NotImplement) {
    // hide/disable rename in UI for this storage
}

// consult driver capabilities before calling
if !driverSupports(storage.Driver, "Rename") { return errs.NotImplement }

func isNotImplement(err error) bool { return errors.Is(err, errs.NotImplement) }

err := fs.Rename(ctx, storage, obj, newName)
if errors.Is(err, errs.NotImplement) {
    hideActionInUI("rename", storage) // degrade gracefully
} else if err != nil { return err }

When it happens

Trigger: Calling an optional driver operation that the specific driver never implemented — e.g. Rename, Move, Copy, Put, or driver-side archive extraction on a read-only or minimal driver whose method body is 'return errs.NotImplement'.

Common situations: UI showing actions (rename/move/upload) for a storage whose driver doesn't support them; automation assuming a uniform driver interface hits a minimal driver; new drivers where only List/Link exist; feature-gating code checking driver capabilities by error type.

Related errors

• not support
• addr is nil
• file sharing cancellation
• file does not exist
• baseResp.Errmsg

AI-assisted analysis of AlistGo/alist@843d9dc814 (2026-08-15). Data as JSON: /api/errors/e1c964007e5762a5. Report an issue: GitHub.