chenhg5/cc-connect · error

write config: %w

Error message

write config: %w

What it means

saveConfig writes the formatted TOML to the temp file with tmp.WriteString; a write failure is cleaned up (temp file closed and removed) and wrapped as "write config: %w". This is the in-place write step of the atomic config save.

Source

Thrown at config/config.go:1564

	dir := filepath.Dir(ConfigPath)
	tmp, err := os.CreateTemp(dir, ".config-*.tmp")
	if err != nil {
		return fmt.Errorf("create temp config: %w", err)
	}
	tmpPath := tmp.Name()

	var buf strings.Builder
	if err := toml.NewEncoder(&buf).Encode(cfg); err != nil {
		tmp.Close()
		os.Remove(tmpPath)
		return fmt.Errorf("encode config: %w", err)
	}

	formatted := formatTOML(buf.String())
	if _, err := tmp.WriteString(formatted); err != nil {
		tmp.Close()
		os.Remove(tmpPath)
		return fmt.Errorf("write config: %w", err)
	}
	if err := tmp.Sync(); err != nil {
		tmp.Close()
		os.Remove(tmpPath)
		return err
	}
	if err := tmp.Close(); err != nil {
		os.Remove(tmpPath)
		return err
	}
	return os.Rename(tmpPath, ConfigPath)
}

// formatTOML post-processes raw TOML encoder output to improve readability:
//   - inserts blank lines before section/array-table headers
//   - removes empty section headers (no key-value pairs between this header and the next)
//
// It deliberately keeps all key-value lines intact, including zero-value ones

View on GitHub (pinned to 4000b2338a)

Solutions

1. Free disk space / raise the quota on the volume holding the config directory and retry the operation.
2. Check the wrapped cause for I/O errors and verify the filesystem health (dmesg, mount options).
3. Move the config to a reliable local filesystem rather than a network mount.

Example fix

// before
// no space check before saving
cfg.Providers = append(cfg.Providers, p)
saveConfig(cfg)
// after
if err := checkDiskSpace(filepath.Dir(config.ConfigPath)); err != nil {
    return err
}
cfg.Providers = append(cfg.Providers, p)
saveConfig(cfg)

if err := checkFreeSpace(filepath.Dir(config.ConfigPath), 1<<20); err != nil {
    return err
}

err := saveConfigOp()
if err != nil && strings.Contains(err.Error(), "write config") {
    time.Sleep(500 * time.Millisecond)
    err = saveConfigOp() // transient I/O: one retry
}

When it happens

Trigger: The WriteString to the already-created temp file fails: filesystem became read-only, disk full/quota hit, I/O error, or the file descriptor entered an error state between creation and write.

Common situations: Disk filling up between temp-file creation and write; NFS/network filesystem failures; container storage limits hit mid-save.

Understand the failure class

Background: "failed to write file", "Could not save figure", "Error saving remote file" — file write failed: causes and fixes across languages and libraries — this error's family across 38 libraries.

Related errors

• write formatted config: %w
• read config: %w
• create temp config: %w
• create temp file: %w
• save config: %w

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/033c884a4b4ae987. Report an issue: GitHub.