anomalyco/sst · error

failed to copy %s to %s: %w

Error message

failed to copy %s to %s: %w

What it means

flattenPackageToRoot iterates every file found in the extracted package and copies it to the flat output directory with copyFile. Any per-file copy failure (missing source, unreadable file, missing destination directory, permission error) is wrapped with both source and destination paths so the offending file is identifiable.

Source

Thrown at pkg/runtime/python/build.go:537

		return nil
	})

	if err != nil {
		return fmt.Errorf("failed to walk extracted directory: %w", err)
	}

	// Create output directory
	if err := os.MkdirAll(outputDir, 0755); err != nil {
		return fmt.Errorf("failed to create output directory: %w", err)
	}

	for _, srcFile := range pythonFiles {
		relPath, _ := filepath.Rel(extractedDir, srcFile)
		destFile := filepath.Join(outputDir, relPath)

		if err := copyFile(srcFile, destFile); err != nil {
			return fmt.Errorf("failed to copy %s to %s: %w", srcFile, destFile, err)
		}
	}

	// Clean up the extracted directory
	os.RemoveAll(extractedDir)

	return nil
}

func installDependenciesForBuild(ctx context.Context, input *runtime.BuildInput, projectInfo *projectInfo) error {
	if err := os.MkdirAll(input.Out(), 0755); err != nil {
		return fmt.Errorf("failed to create output directory: %w", err)
	}

	requirementsFile := filepath.Join(input.Out(), "requirements.txt")
	if err := generateOrCopyRequirementsFile(ctx, projectInfo, requirementsFile); err != nil {
		return fmt.Errorf("failed to generate requirements file: %w", err)
	}

View on GitHub (pinned to a0bd20f762)

Solutions

1. Run the build again — transient issues (deleted temp files, races with other builds) often resolve; avoid running concurrent builds into the same output dir
2. Inspect the srcFile/destFile paths in the message and check permissions and existence of the file and its destination parent directory
3. Free disk space (ENOSPC shows up as copy failures)
4. If a specific archive file is consistently failing, reinstall/refresh the dependency or remove a broken symlink before building

Example fix

// before
if err := copyFile(srcFile, destFile); err != nil {
	return fmt.Errorf("failed to copy %s to %s: %w", srcFile, destFile, err)
}
// after (ensure destination dir exists first)
os.MkdirAll(filepath.Dir(destFile), 0755)
if err := copyFile(srcFile, destFile); err != nil {
	return fmt.Errorf("failed to copy %s to %s: %w", srcFile, destFile, err)
}

for _, f := range filesToCopy {
	if fi, err := os.Lstat(f); err != nil || !fi.Mode().IsRegular() {
		// skip or fix broken symlinks / unreadable files before copying
	}
}
dfOut, _ := exec.Command("df", "-h", outputDir).Output() // ensure free space

func isRegularReadable(path string) bool {
	fi, err := os.Stat(path)
	return err == nil && fi.Mode().IsRegular() && unix.Access(path, unix.R_OK) == nil
}

err := buildPython()
var pe *fs.PathError
switch {
case errors.As(err, &pe) && errors.Is(pe.Err, syscall.ENOSPC):
	freeDiskAndRetry()
case errors.As(err, &pe) && errors.Is(pe.Err, syscall.EACCES):
	fixPerms(pe.Path)
}

When it happens

Trigger: copyFile(srcFile, destFile) fails: srcFile disappeared or is unreadable (permissions, broken symlink), destFile's parent directory wasn't created, or the destination filesystem is full/read-only.

Common situations: A file inside the extracted wheel/archive is a dangling symlink or has restrictive modes; nested subdirectories whose parent dirs were never MkdirAll'd before copy; ENOSPC when copying a large dependency tree into the build output.

Related errors

• failed to create output directory: %w
• failed to copy source files: %w
• failed to copy directory %s: %w
• failed to copy file %s: %w
• failed to move extracted package: %w

AI-assisted analysis of anomalyco/sst@a0bd20f762 (2026-08-30). Data as JSON: /api/errors/a53fffe3b757fb49. Report an issue: GitHub.