go-task/task · error

task: %w "%s"

Error message

task: %w "%s"

What it means

The `sources:` fingerprint mechanism validates its `method:` attribute against known checkers (timestamp, checksum, none). An unknown method returns this error, wrapped with ErrInvalidMethod (so errors.Is(err, task.ErrInvalidMethod) works). It comes from NewSourcesChecker via resolveSourcesChecker when setting up a task's up-to-date checking.

Source

Thrown at internal/fingerprint/sources.go:22

	"fmt"

	"github.com/go-task/task/v3/errors"
)

// ErrInvalidMethod lets callers that only need a fingerprint value tell a bad
// method name apart from a checker failing on the sources themselves.
var ErrInvalidMethod = errors.New("invalid method")

func NewSourcesChecker(method, tempDir string, dry bool) (SourcesCheckable, error) {
	switch method {
	case "timestamp":
		return NewTimestampChecker(tempDir, dry), nil
	case "checksum":
		return NewChecksumChecker(tempDir, dry), nil
	case "none":
		return NoneChecker{}, nil
	default:
		return nil, fmt.Errorf(`task: %w "%s"`, ErrInvalidMethod, method)
	}
}

View on GitHub (pinned to 385e5ad92a)

Solutions

1. Use one of the supported methods: timestamp, checksum, or none
2. Omit `method:` entirely to use the default instead of guessing a value
3. Check Task's documentation/version — supported methods are limited to these three

Example fix

# before
sources:
  - src/**/*
  method: hash
# after
sources:
  - src/**/*
  method: checksum

var validMethods = map[string]bool{"timestamp":true,"checksum":true,"none":true}
if m := taskDef.Method; m != "" && !validMethods[m] {
  return fmt.Errorf("invalid sources method %q", m)
}

err := t.Run(ctx)
if err != nil && errors.Is(err, task.ErrInvalidMethod) {
  // rewrite method to "checksum" (default) and retry
}

When it happens

Trigger: A task defines `sources:` with `method: <value>` where <value> is not timestamp, checksum, or none; resolveSourcesChecker then fails while building the task execution plan.

Common situations: Typos like `method: hash` or `method: mtime`, copying config from other build tools (make, bazel) with different option names, or uppercase values (`method: Checksum`).

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• invalid method
• task: Included Taskfiles can't have dotenv declarations. Ple
• loop var must be a delimiter-separated string, list or a map
• task: invalid run "%s"
• task: output style %q not recognized

AI-assisted analysis of go-task/task@385e5ad92a (2026-09-05). Data as JSON: /api/errors/15fff92c757dab92. Report an issue: GitHub.