golangci/golangci-lint · error

%s is a formatter

Error message

%s is a formatter

What it means

Linters.validateNoFormatters rejects any name in linters.enable or linters.disable that is actually a formatter. In golangci-lint v2, formatters were split out of linters, so configuring e.g. 'gofmt' under linters is an error rather than silently accepted.

Source

Thrown at pkg/config/linters.go:44

func (l *Linters) Validate() error {
	validators := []func() error{
		l.Exclusions.Validate,
		l.validateNoFormatters,
	}

	for _, v := range validators {
		if err := v(); err != nil {
			return err
		}
	}

	return nil
}

func (l *Linters) validateNoFormatters() error {
	for _, n := range slices.Concat(l.Enable, l.Disable) {
		if slices.Contains(getAllFormatterNames(), n) {
			return fmt.Errorf("%s is a formatter", n)
		}
	}

	return nil
}

func getAllFormatterNames() []string {
	return []string{"gci", "gofmt", "gofumpt", "goimports", "golines", "swaggo"}
}

View on GitHub (pinned to ed7a235d2d)

Solutions

1. Move formatter names from linters.enable to formatters.enable
2. Remove formatter names from linters.disable and use formatters settings instead
3. Run 'golangci-lint migrate' to auto-convert a v1 config to v2

Example fix

# before
linters:
  enable:
    - gofmt
    - revive
# after
linters:
  enable:
    - revive
formatters:
  enable:
    - gofmt

formatterNames := getAllFormatterNames()
for _, n := range slices.Concat(cfg.Linters.Enable, cfg.Linters.Disable) {
	if slices.Contains(formatterNames, n) {
		return fmt.Errorf("%s is a formatter; move it to formatters", n)
	}
}

if err := linters.Validate(); err != nil { log.Fatalf("linters config: %v", err) }

When it happens

Trigger: v1-style config where gofmt/goimports/gofumpt etc. are listed under linters.enable or linters.disable; running golangci-lint v2 on an unmigrated config.

Common situations: Upgrading from golangci-lint v1 to v2 without running the migration; copy-pasting old configs; disabling a formatter via linters.disable.

Related errors

• %s is not a linter, it cannot be enabled or disabled
• at least %d of (text, source, path[-except], linters) should
• %s is not a formatter
• error in exclude rule #%d: %w
• invalid preset: %s

AI-assisted analysis of golangci/golangci-lint@ed7a235d2d (2026-09-02). Data as JSON: /api/errors/d64beb2c1a3b0825. Report an issue: GitHub.