microsoft/typescript-go · error

failed to create alloc profile file: %w

Error message

failed to create alloc profile file: %w

What it means

SaveAllocProfile could not os.Create the alloc profile file in an existing directory. Mirrors the heap-file error: mkdir succeeded but creating the output file failed — permission mode on the directory, ENOSPC, filesystem policy, or I/O error. No profile is written.

Source

Thrown at internal/pprof/pprof.go:154

	runtime.GC()
	if err := pprof.Lookup("heap").WriteTo(heapFile, 0); err != nil {
		os.Remove(heapProfilePath)
		return "", fmt.Errorf("failed to write heap profile: %w", err)
	}

	return heapProfilePath, nil
}

// SaveAllocProfile saves an allocation profile to the specified directory.
func SaveAllocProfile(profileDir string) (string, error) {
	if err := os.MkdirAll(profileDir, 0o755); err != nil {
		return "", fmt.Errorf("failed to create profile directory: %w", err)
	}

	allocProfilePath := filepath.Join(profileDir, fmt.Sprintf("%d-%d-allocprofile.pb.gz", os.Getpid(), time.Now().UnixMilli()))
	allocFile, err := os.Create(allocProfilePath)
	if err != nil {
		return "", fmt.Errorf("failed to create alloc profile file: %w", err)
	}
	defer allocFile.Close()

	if err := pprof.Lookup("allocs").WriteTo(allocFile, 0); err != nil {
		os.Remove(allocProfilePath)
		return "", fmt.Errorf("failed to write alloc profile: %w", err)
	}

	return allocProfilePath, nil
}

// RunGC triggers garbage collection.
func RunGC() {
	runtime.GC()
}

View on GitHub (pinned to 1bcfa18d79)

Solutions

1. Probe writability (create a temp file) in the target directory before the real call
2. Fix ownership/permissions or relocate profileDir
3. Free disk space

if f, err := os.CreateTemp(profileDir, "probe-*"); err != nil {
	return fmt.Errorf("alloc dump target unusable: %w", err)
} else {
	f.Close()
	os.Remove(f.Name())
}

if _, err := pprof.SaveAllocProfile(dir); err != nil {
	var perr *fs.PathError
	if errors.As(err, &perr) && (perr.Err == syscall.EACCES || perr.Err == syscall.ENOSPC) {
		return pprof.SaveAllocProfile(os.TempDir())
	}
	return "", err
}

When it happens

Trigger: Directory writable for mkdir (already existed) but file creation denied; disk full; SELinux/AppArmor denial; NFS create refusal.

Common situations: Existing directories with restrictive modes (root-created dump dirs); quota-exceeded volumes; security-hardened hosts.

Related errors

• failed to create CPU profile file: %w
• failed to create heap profile file: %w
• failed to write alloc profile: %w
• failed to create profile directory: %w
• failed to write heap profile: %w

AI-assisted analysis of microsoft/typescript-go@1bcfa18d79 (2026-08-16). Data as JSON: /api/errors/28ecbf11cb46b378. Report an issue: GitHub.