gohugoio/hugo · error

errConfigNotSet

errConfigNotSet

Error message

config not set

What it means

A sentinel error (errConfigNotSet) returned by hugoBuilder.withConfE and withConfOrOldConfE when the builder's commonConfig has not been loaded yet (c.conf is nil, and for the OrOld variant c.confOld is also nil). It guards against operating on a builder before loadConfig has succeeded, or during a config reload window when c.conf is temporarily set to nil.

Source

Thrown at commands/hugobuilder.go:81

	// May be nil.
	s *serverCommand

	// Currently only set when in "fast render mode".
	changeDetector *fileChangeDetector
	visitedURLs    *types.EvictingQueue[string]

	fullRebuildSem *semaphore.Weighted
	debounce       func(f func())

	onConfigLoaded func(reloaded bool) error

	fastRenderMode     bool
	showErrorInBrowser bool

	errState hugoBuilderErrState
}

var errConfigNotSet = errors.New("config not set")

func (c *hugoBuilder) withConfE(fn func(conf *commonConfig) error) error {
	c.confmu.Lock()
	defer c.confmu.Unlock()
	if c.conf == nil {
		return errConfigNotSet
	}
	return fn(c.conf)
}

func (c *hugoBuilder) withConf(fn func(conf *commonConfig)) {
	c.confmu.Lock()
	defer c.confmu.Unlock()
	fn(c.conf)
}

func (c *hugoBuilder) withConfOrOldConf(fn func(conf *commonConfig)) {
	c.confmu.Lock()

View on GitHub ↗ (pinned to 8a468df065)

Solutions

1. Fix whatever made the initial config load fail (check earlier error output for the real config error) and rerun the command.
2. If running `hugo server`, restart the server so a clean config load happens before builds.
3. If developing against this code, ensure loadConfig is called and returns nil before invoking build/watch methods on hugoBuilder.

// ensure config is loaded before building
if cfg == nil {
    log.Fatal("load config before invoking build")
}
b := newHugoBuilder(r, cfg)

if err := b.build(); err != nil {
    if err.Error() == "config not set" {
        // programming error: builder used before initialization
        panic(err)
    }
    return err
}

When it happens

Trigger: Any code path calling withConfE/withConfOrOldConfE before hugoBuilder.loadConfig completes, or during reloadConfig where c.conf is nil-ed while ConfigFromConfig runs and both conf and confOld are unavailable; also if the initial config load failed and a later build/watch callback still fires.

Common situations: Hitting a file-watch rebuild while the initial config load failed (e.g. broken hugo.toml during `hugo server`), or race-adjacent scenarios where a server callback runs before the first successful config load.

Related errors

• failed to compile whitelist pattern %q: %w
• failed to load config: %v
• failed to init config: %w
• no filesystem provided
• failed to parse timeout: %s

AI-assisted analysis of gohugoio/hugo@8a468df065 (2026-07-31). Data as JSON: /data/errors/88d4e453dc091c34.json. Report an issue: GitHub ↗.