What causes "locales not found in %s" in kataras/iris?

Check the listed asset names and rename files so they contain a registered language tag (e.g. locales/en-US.yml).

locales not found in %s

Error message

locales not found in %s

What it means

The file-based loader (load, used by i18n.Glob/FS/Assets) parses locale files matched by assetNames and stores them per language. If after loading all files cat.Locales is empty, it returns "locales not found in <file1, file2, ...>". This means none of the asset files matched a registered language or none produced a stored locale.

Source

Thrown at i18n/loader.go:205

				b, err := asset(fileName)
				if err != nil {
					return nil, err
				}

				if err = unmarshal(b, &keyValues); err != nil {
					return nil, err
				}
			}

			err = cat.Store(langIndex, keyValues)
			if err != nil {
				return nil, err
			}
		}

		if n := len(cat.Locales); n == 0 {
			return nil, fmt.Errorf("locales not found in %s", strings.Join(assetNames, ", "))
		} else if options.Strict && n < len(m.Languages) {
			return nil, fmt.Errorf("locales expected to be %d but %d parsed", len(m.Languages), n)
		}

		return cat, nil
	}
}

func unmarshalINI(data []byte, v any) error {
	f, err := ini.Load(data)
	if err != nil {
		return err
	}

	m := *v.(*map[string]any)

	// Includes the ini.DefaultSection which has the root keys too.
	// We don't have to iterate to each section to find the subsection,

View on GitHub (pinned to 7bedaf55a0)

Solutions

Check the listed asset names and rename files so they contain a registered language tag (e.g. locales/en-US.yml).
Verify the Glob/FS pattern actually matches the files (print the matched names).
Ensure the languages passed to New/i18n match the file language tags.
Confirm embedded FS (go:embed) paths are relative to the embed root as expected.

Example fix

// before (unrecognized names)
locales/locale-en-US.yaml
// after
locales/en-US.yaml

Defensive patterns

Strategy: validation

Validate before calling

// verify files match expected naming before load
matches, _ := filepath.Glob("./locales/*.yaml")
if len(matches) == 0 {
    return fmt.Errorf("no locale files found in ./locales")
}
for _, f := range matches {
    base := filepath.Base(f)
    if !strings.Contains(base, "en") {
        log.Printf("warning: %s does not encode a language tag", base)
    }
}

Try / catch

localizer, err := i18n.Glob("./locales/*/*.yaml")(matcher)
if err != nil && strings.Contains(err.Error(), "locales not found in") {
    return fmt.Errorf("no locale files matched registered languages: %w", err)
}

Prevention

Name files with the language tag: en-US.yaml, el-GR.ini.
Verify Glob/embed patterns match the actual directory layout.
Keep file language tags in sync with languages registered in New.
Log matched asset names during load to catch naming drift.

When it happens

Trigger: Calling i18n.Glob("./locales/*/*.yaml") (or FS/Assets) where ParseLanguageFiles found no files matching the registered languages' tags — filenames lack language names, wrong directory layout, or registered languages don't appear in any filename.

Common situations: Naming files locale-en.yml instead of en.yml (pattern the parser doesn't expect), files in a layout Glob doesn't match, embedded FS paths differing from local paths, or New registered with languages absent from the folder.

Related errors

AI-assisted analysis of kataras/iris@7bedaf55a0 (2026-08-30). Data as JSON: /api/errors/d1cafe6a59188d6b. Report an issue: GitHub.