What causes "%s is not a valid glob pattern with error: %w" in kovidgoyal/kitty?

Fix the glob pattern syntax (balanced brackets, valid character classes)

%s is not a valid glob pattern with error: %w

Error message

%s is not a valid glob pattern with error: %w

What it means

resolve_file_spec expands a copy-instruction file spec with doublestar.FilepathGlob when it contains glob metacharacters. If the pattern is malformed (e.g. unbalanced '['), doublestar returns an error which is wrapped with the spec.

Source

Thrown at kittens/ssh/config.go:182

	}
	ans = []*EnvInstruction{ei}
	return
}

var paths_ctx *paths.Ctx

func resolve_file_spec(spec string, is_glob bool) ([]string, error) {
	if paths_ctx == nil {
		paths_ctx = &paths.Ctx{}
	}
	ans := os.ExpandEnv(paths_ctx.ExpandHome(spec))
	if !filepath.IsAbs(ans) {
		ans = paths_ctx.AbspathFromHome(ans)
	}
	if is_glob {
		files, err := doublestar.FilepathGlob(ans)
		if err != nil {
			return nil, fmt.Errorf("%s is not a valid glob pattern with error: %w", spec, err)
		}
		if len(files) == 0 {
			return nil, fmt.Errorf("%s matches no files", spec)
		}
		return files, nil
	}
	err := unix.Access(ans, unix.R_OK)
	if err != nil {
		if errors.Is(err, os.ErrNotExist) {
			return nil, fmt.Errorf("%s does not exist", spec)
		}
		return nil, fmt.Errorf("Cannot read from: %s with error: %w", spec, err)
	}
	return []string{ans}, nil
}

func get_arcname(loc, dest, home string) (arcname string) {
	if dest != "" {

View on GitHub (pinned to 6d5d0c4406)

Solutions

Fix the glob pattern syntax (balanced brackets, valid character classes)
Escape literal metacharacters if the filename really contains them
Test the pattern with a glob tester before putting it in config

Example fix

// before
copy: ~/logs/[2024-
// after
copy: ~/logs/2024-*

Defensive patterns

Strategy: validation

Validate before calling

if _, err := doublestar.FilepathGlob(pattern); err != nil { /* reject pattern before config load */ }

Type guard

func isValidGlob(p string) bool { _, err := doublestar.FilepathGlob(p); return err == nil }

Prevention

Lint glob patterns in config during CI
Escape literal brackets/asterisks in filenames

When it happens

Trigger: A copy: or env copy spec like '~/data/[a-' where the glob syntax itself is invalid.

Common situations: Windows-style paths with brackets, typos in character classes, or accidentally treating a literal filename containing '*' or '[' as a glob.

Related errors

AI-assisted analysis of kovidgoyal/kitty@6d5d0c4406 (2026-08-27). Data as JSON: /api/errors/71a5c43b5b6d4a03. Report an issue: GitHub.