github/copilot-sdk · error

failed to hash runtime assets

Error message

failed to hash runtime assets: %w

What it means

This error wraps a failure from sha256File when hashing the freshly created runtime assets archive. The bundler computes the SHA-256 digest to embed in bundle metadata; if the file cannot be opened or read, buildBundle fails with this message.

Solutions

1. Re-run the bundler; transient read errors usually clear on retry
2. Confirm the assets artifact path exists and is readable in the output directory (ls -l)
3. Check disk health / available space on the output volume
4. Log the wrapped cause (%w) to distinguish open failures from read failures

Example fix

// before
assetsHash, err := sha256File(assetsArtifactPath)
if err != nil {
	return bundleArtifacts{}, fmt.Errorf("failed to hash runtime assets: %w", err)
}
// after
assetsHash, err := sha256File(assetsArtifactPath)
if err != nil {
	if os.IsNotExist(err) {
		return bundleArtifacts{}, fmt.Errorf("runtime assets missing at %s: %w", assetsArtifactPath, err)
	}
	return bundleArtifacts{}, fmt.Errorf("failed to hash runtime assets: %w", err)
}

if fi, err := os.Stat(assetsArtifactPath); err != nil || fi.Size() == 0 {
	return fmt.Errorf("assets artifact %s missing or empty before hashing", assetsArtifactPath)
}

assetsHash, err := sha256File(assetsArtifactPath)
if err != nil {
	if os.IsNotExist(err) { /* regenerate archive and retry once */ }
	return fmt.Errorf("failed to hash runtime assets: %w", err)
}

When it happens

Trigger: sha256File(assetsArtifactPath) returns an error right after createRuntimeAssetsArchive succeeds — typically the assets file is missing/unreadable or an I/O error occurs while reading it.

Common situations: Antivirus or another process removing temp files between creation and hashing; disk read errors; permissions changed on the output directory; filesystem race in a shared tmpdir.

Understand the failure class

Background: "failed to read file", EACCES, ENOENT and "could not read <path>" errors: when a program can't read a file from disk — this error's family across 49 libraries.

Related errors

• failed to write runtime assets
• runtime package contains no retained assets
• failed to read existing Go file
• Failed to read runtime package entry
• SessionFS.InitialWorkingDirectory is required

AI-assisted analysis of github/copilot-sdk@cd8cf15dc3 (2026-09-09). Data as JSON: /api/errors/71676825905f4e8d. Report an issue: GitHub.

Appendix: source

Thrown at go/cmd/bundler/main.go:503

		tempDir,
		"package/prebuilds/"+info.runtimePlatform+"/"+wrapperName,
		wrapperName,
	); err != nil {
		return bundleArtifacts{}, fmt.Errorf("runtime package is missing prebuilds/%s/%s: %w", info.runtimePlatform, wrapperName, err)
	}
	wrapperHash, err := sha256File(rawWrapperPath)
	if err != nil {
		return bundleArtifacts{}, fmt.Errorf("failed to hash runtime wrapper: %w", err)
	}
	if err := compressZstdFile(rawWrapperPath, wrapperArtifactPath); err != nil {
		return bundleArtifacts{}, fmt.Errorf("failed to write runtime wrapper: %w", err)
	}
	if err := createRuntimeAssetsArchive(tarballPath, assetsArtifactPath, info); err != nil {
		return bundleArtifacts{}, fmt.Errorf("failed to write runtime assets: %w", err)
	}
	assetsHash, err := sha256File(assetsArtifactPath)
	if err != nil {
		return bundleArtifacts{}, fmt.Errorf("failed to hash runtime assets: %w", err)
	}

	fmt.Printf("Successfully created %s\n", outputPath)
	fmt.Printf("Successfully created %s\n", runtimeArtifactPath)
	fmt.Printf("Successfully created %s\n", wrapperArtifactPath)
	fmt.Printf("Successfully created %s\n", assetsArtifactPath)
	return bundleArtifacts{outputPath, binaryHash, runtimeArtifactPath, runtimeHash, wrapperArtifactPath, wrapperHash, assetsArtifactPath, assetsHash}, nil
}

func filesExist(paths ...string) bool {
	for _, path := range paths {
		if _, err := os.Stat(path); err != nil {
			return false
		}
	}
	return true
}

View on GitHub (pinned to cd8cf15dc3)