pulumi/pulumi · error

Could not find `yarn` executable. Install yarn and make sure

Error message

Could not find `yarn` executable.
Install yarn and make sure it is in your PATH.

What it means

newYarnClassic could not find the 'yarn' executable on PATH (exec.LookPath returned exec.ErrNotFound), so Yarn Classic package-manager support cannot be used. The SDK raises a descriptive error telling the user to install yarn.

Source

Thrown at sdk/nodejs/npm/yarn.go:49

	"github.com/pulumi/pulumi/sdk/v3/go/common/util/errutil"
	"github.com/pulumi/pulumi/sdk/v3/go/common/util/fsutil"
	"github.com/pulumi/pulumi/sdk/v3/go/common/util/logging"
)

// yarnClassic is an implementation of PackageManager that uses Yarn Classic,
// which is the v1.x.y line, to install dependencies.
type yarnClassic struct {
	executable string
}

// Assert that YarnClassic is an instance of PackageManager.
var _ PackageManager = &yarnClassic{}

func newYarnClassic() (*yarnClassic, error) {
	yarnPath, err := exec.LookPath("yarn")
	if err != nil {
		if errors.Is(err, exec.ErrNotFound) {
			return nil, errors.New("Could not find `yarn` executable.\n" +
				"Install yarn and make sure it is in your PATH.")
		}
		return nil, err
	}
	return &yarnClassic{
		executable: yarnPath,
	}, nil
}

func (yarn *yarnClassic) Name() string {
	return "yarn"
}

func (yarn *yarnClassic) Version() (semver.Version, error) {
	cmd := exec.Command(yarn.executable, "--version")
	output, err := cmd.Output()
	if err != nil {
		return semver.Version{}, errutil.ErrorWithStderr(err, cmd.String())

View on GitHub (pinned to 793f7b2e16)

Solutions

1. Install yarn: corepack enable (ships with Node) or npm install -g yarn
2. Verify with 'which yarn' / 'yarn --version' in the same shell that runs pulumi
3. Add the yarn bin directory to PATH in your shell profile, CI environment, or container image
4. Alternatively switch the project to npm or pnpm if yarn is not required

Example fix

// before: command not found
pulumi install
// after
corepack enable && pulumi install

which yarn || { echo 'yarn not found; run: corepack enable'; exit 1; }
yarn --version

y, err := newYarnClassic()
if err != nil {
  if strings.Contains(err.Error(), "Could not find `yarn` executable") {
    // fall back to npm or instruct user to install yarn
  }
  return err
}

When it happens

Trigger: Using the yarn package-manager integration (e.g. PULUMI_YARN / yarn-based NodeJS project install) when no 'yarn' binary is resolvable via PATH.

Common situations: Yarn never installed on the machine/CI image; yarn installed via a version manager (nvm/volta/corepack) whose bin dir isn't on PATH in the current shell or container; running pulumi from a GUI/service with a minimal PATH.

Related errors

• Problem executing program (could not run language executor):
• error while looking for fnm: %w
• could not find executable %q: %w
• find npm: %w
• the project's manifest is package.yaml, which requires pnpm,

AI-assisted analysis of pulumi/pulumi@793f7b2e16 (2026-08-31). Data as JSON: /api/errors/e0d9abc217a07fe8. Report an issue: GitHub.