golangci/golangci-lint · error

can't read viper config

Error message

can't read viper config: %w

What it means

parseConfig calls viper.ReadInConfig; if reading fails for reasons other than "config file not found" (parse errors, permission, IO), the error is wrapped as "can't read viper config" and config loading stops.

Solutions

1. Validate the YAML/JSON config file syntax (yamllint or a YAML parser) and fix syntax errors
2. Check file permissions so the lint process can read the config file
3. Use `golangci-lint config path` to see which config file is being picked up; remove or fix stale ones
4. Read the wrapped %w error — viper reports the file and line of parse failures

Example fix

# before (invalid YAML)
issues:
	exclude-dirs:
  - vendor
# after
issues:
  exclude-dirs:
    - vendor

func validYAML(path string) error {
	data, err := os.ReadFile(path)
	if err != nil {
		return err
	}
	var v map[string]any
	return yaml.Unmarshal(data, &v)
}
// run in CI before golangci-lint: validYAML(".golangci.yml")

When it happens

Trigger: A config file exists at the resolved location but viper cannot read/parse it: malformed YAML/JSON/TOML syntax, unreadable file permissions, unreadable config directory (setConfigDir side effects happen after), or a corrupted search path.

Common situations: Hand-edited .golangci.yml with indentation/tab mistakes; merge-conflict markers left in the file; root-owned config in CI containers; a stray .golangci.yaml in a parent directory with bad syntax.

Related errors

• can't unmarshal config by viper (flags, file)
• can't unmarshal config by viper (flags)
• failed to calculate config salt
• failed to JSON marshal config linter settings
• analyzer doesn't have settings

AI-assisted analysis of golangci/golangci-lint@ed7a235d2d (2026-09-02). Data as JSON: /api/errors/6eb81fa21dafa7c6. Report an issue: GitHub.

Appendix: source

Thrown at pkg/config/base_loader.go:168

		searchPaths = append(searchPaths, home)
	}

	return searchPaths
}

func (l *BaseLoader) parseConfig() error {
	if err := l.viper.ReadInConfig(); err != nil {
		if _, ok := errors.AsType[viper.ConfigFileNotFoundError](err); ok {
			// Load configuration from flags only.
			err = l.viper.Unmarshal(l.cfg, customDecoderHook())
			if err != nil {
				return fmt.Errorf("can't unmarshal config by viper (flags): %w", err)
			}

			return nil
		}

		return fmt.Errorf("can't read viper config: %w", err)
	}

	err := l.setConfigDir()
	if err != nil {
		return err
	}

	// Load configuration from all sources (flags, file).
	if err := l.viper.Unmarshal(l.cfg, customDecoderHook()); err != nil {
		return fmt.Errorf("can't unmarshal config by viper (flags, file): %w", err)
	}

	if l.cfg.IsInternalTest() { // just for testing purposes: to detect config file usage
		_, _ = fmt.Fprintln(logutils.StdOut, "test")
		os.Exit(exitcodes.Success)
	}

	return nil

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