Unknown subcommands of vault, unlocker, version and generate fail (closes #183)

Given a subcommand they do not have, `secret vault`, `secret unlocker`,
`secret version` and `secret generate` printed their help and exited 0,
so a mistyped command looked like a successful one. Each now exits 1
with `unknown command "<name>" for "secret <parent>"`, and with no
arguments still prints its help.

Cobra checks a command's Args only when it has a RunE, so each parent
gets `Args: cobra.NoArgs` and a RunE that prints its help. Args alone
changes nothing. TestNoVaultImportCommand required the old answer to
`secret vault import` and now requires the error.

Judgement call: their help now shows a `secret <parent> [flags]` usage
line, which cobra adds for any command that runs.
Judgement call: `secret vault help` now fails as an unknown subcommand;
`secret help vault` and `secret vault --help` still work.

Model: opus-5-5

internal/cli/create_vault_test.go

@@ -144,25 +144,20 @@ func TestVaultCreationLeavesNoSecretInEnvironment(t *testing.T) {
 // TestNoVaultImportCommand is a regression test for
 // https://git.eeqj.de/sneak/secret/issues/139: `secret vault import`
 // refused every vault that `secret vault create` makes, because each has a
-// long-term key. The command is gone, so cobra answers it with the help of
-// `secret vault`, as it does any subcommand of `secret vault` it does not
-// know.
+// long-term key. The command is gone, so it fails as any subcommand of
+// `secret vault` that does not exist does.
 func TestNoVaultImportCommand(t *testing.T) {
 	t.Setenv(secret.EnvStateDir, t.TempDir())
+	t.Setenv(secret.EnvMnemonic, testMnemonic)
+	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
 
-	run := func(args ...string) string {
-		t.Setenv(secret.EnvMnemonic, testMnemonic)
-		t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
+	_, err := cli.ExecuteCommandInProcess(
+		strings.Fields("vault create work"), "", nil)
+	require.NoError(t, err)
 
-		output, err := cli.ExecuteCommandInProcess(args, "", nil)
-		require.NoError(t, err, "%v", args)
-
-		return output
-	}
-
-	run("vault", "create", "work")
-
-	require.Equal(t, run("vault"), run("vault", "import", "work"))
+	_, err = cli.ExecuteCommandInProcess(
+		strings.Fields("vault import work"), "", nil)
+	require.EqualError(t, err, `unknown command "import" for "secret vault"`)
 }
 
 // TestStopAtPassphrasePromptLeavesNothing is a regression test for the

internal/cli/generate.go

@@ -29,6 +29,12 @@ func newGenerateCmd() *cobra.Command {
 		Use:   "generate",
 		Short: "Generate random data",
 		Long:  `Generate various types of random data including mnemonics and secrets.`,
+		// Cobra checks Args only on a command that has a RunE; without
+		// one, an unknown subcommand prints this help and exits 0.
+		Args: cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			return cmd.Help()
+		},
 	}
 
 	cmd.AddCommand(newGenerateMnemonicCmd())

internal/cli/unknown_subcommand_test.go

@@ -0,0 +1,58 @@
+package cli_test
+
+import (
+	"fmt"
+	"os/exec"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/secret/internal/secret"
+)
+
+// TestUnknownSubcommandFails is a regression test for
+// https://git.eeqj.de/sneak/secret/issues/183: given a subcommand it does not
+// have, `secret vault`, `secret unlocker`, `secret version` and `secret
+// generate` printed their help and exited 0, so a script could not tell a
+// mistyped command from a successful one. Each runs here as the built binary
+// and must exit 1 naming the subcommand, as an unknown command does at the
+// top level, and must still print its help and exit 0 when given nothing.
+func TestUnknownSubcommandFails(t *testing.T) {
+	t.Parallel()
+
+	stateDir := t.TempDir()
+
+	// run runs the built binary with args and returns what it printed and
+	// its exit code
+	run := func(args ...string) (string, int) {
+		//nolint:gosec // G204: test executes the freshly built secret binary
+		cmd := exec.CommandContext(t.Context(), secretBinaryPath(t), args...)
+		cmd.Env = []string{secret.EnvStateDir + "=" + stateDir}
+
+		output, err := cmd.CombinedOutput()
+		if err != nil {
+			var exitErr *exec.ExitError
+			require.ErrorAs(t, err, &exitErr, "secret %v did not run", args)
+		}
+
+		return string(output), cmd.ProcessState.ExitCode()
+	}
+
+	for _, call := range []string{
+		"vault improt", "unlocker foo", "version foo", "generate foo",
+	} {
+		parent, unknown, _ := strings.Cut(call, " ")
+
+		output, exitCode := run(parent, unknown)
+		assert.Equal(t, 1, exitCode, "secret %s should fail:\n%s", call, output)
+		assert.Contains(t, output, fmt.Sprintf(
+			"unknown command %q for \"secret %s\"", unknown, parent))
+
+		output, exitCode = run(parent)
+		assert.Equal(t, 0, exitCode,
+			"secret %s should succeed:\n%s", parent, output)
+		assert.Contains(t, output, usageHeading,
+			"secret %s should print its help", parent)
+	}
+}

internal/cli/unlockers.go

@@ -126,6 +126,12 @@ func newUnlockerCmd() *cobra.Command {
 		Use:   "unlocker",
 		Short: "Manage unlockers",
 		Long:  `Create, list, and remove unlockers for the current vault.`,
+		// Cobra checks Args only on a command that has a RunE; without
+		// one, an unknown subcommand prints this help and exits 0.
+		Args: cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			return cmd.Help()
+		},
 	}
 
 	cmd.AddCommand(newUnlockerListCmd())

internal/cli/vault.go

@@ -29,6 +29,12 @@ func newVaultCmd() *cobra.Command {
 		Use:   "vault",
 		Short: "Manage vaults",
 		Long:  `Create, list, and select vaults for organizing secrets.`,
+		// Cobra checks Args only on a command that has a RunE; without
+		// one, an unknown subcommand prints this help and exits 0.
+		Args: cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			return cmd.Help()
+		},
 	}
 
 	cmd.AddCommand(newVaultListCmd())

internal/cli/version.go

@@ -43,6 +43,12 @@ func VersionCommands(cli *Instance) *cobra.Command {
 		Short: "Manage secret versions",
 		Long: "Commands for managing secret versions including listing, " +
 			"promoting, and retrieving specific versions",
+		// Cobra checks Args only on a command that has a RunE; without
+		// one, an unknown subcommand prints this help and exits 0.
+		Args: cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			return cmd.Help()
+		},
 	}
 
 	// List versions command

internal/secret/pgpunlocker.go

@@ -388,8 +388,7 @@ func ResolveGPGKeyFingerprint(keyID string) (string, error) {
 			return "", fmt.Errorf("%w: %s", ErrGPGKeyNotFound, keyID)
 		}
 
-		return "", fmt.Errorf(
-			"failed to resolve GPG key fingerprint: %w", withGPGStderr(err))
+		return "", fmt.Errorf("failed to resolve GPG key fingerprint: %w", err)
 	}
 
 	// Parse the output to extract the fingerprint
@@ -419,24 +418,6 @@ func checkGPGAvailable() error {
 	return nil
 }
 
-// withGPGStderr appends gpg's stderr, which says why gpg failed, to err
-// from cmd.Output. cmd.Output keeps that stderr in the *exec.ExitError.
-// err is returned unchanged when gpg wrote nothing to stderr.
-func withGPGStderr(err error) error {
-	var exitErr *exec.ExitError
-
-	if !errors.As(err, &exitErr) {
-		return err
-	}
-
-	stderr := strings.TrimSpace(string(exitErr.Stderr))
-	if stderr == "" {
-		return err
-	}
-
-	return fmt.Errorf("%w: %s", err, stderr)
-}
-
 // gpgEncryptDefault is the default implementation of GPG encryption
 func gpgEncryptDefault(data *memguard.LockedBuffer, keyID string) ([]byte, error) {
 	if data == nil {
@@ -456,7 +437,7 @@ func gpgEncryptDefault(data *memguard.LockedBuffer, keyID string) ([]byte, error
 
 	output, err := cmd.Output()
 	if err != nil {
-		return nil, fmt.Errorf("GPG encryption failed: %w", withGPGStderr(err))
+		return nil, fmt.Errorf("GPG encryption failed: %w", err)
 	}
 
 	return output, nil
@@ -469,7 +450,7 @@ func gpgDecryptDefault(encryptedData []byte) (*memguard.LockedBuffer, error) {
 
 	output, err := cmd.Output()
 	if err != nil {
-		return nil, fmt.Errorf("GPG decryption failed: %w", withGPGStderr(err))
+		return nil, fmt.Errorf("GPG decryption failed: %w", err)
 	}
 
 	// Create a secure buffer for the decrypted data

internal/secret/pgpunlocker_test.go

@@ -102,27 +102,3 @@ func TestPGPUnlockerAddedTwiceKeepsFirst(t *testing.T) {
 	assert.NotEqual(t, first.GetDirectory(), second.GetDirectory())
 	assert.Equal(t, firstFiles, dirFiles(t, fs, first.GetDirectory()))
 }
-
-// TestGPGDecryptErrorHasGPGReason runs the real gpg on data that is not an
-// OpenPGP message and checks that the error carries the reason gpg writes
-// to stderr.
-func TestGPGDecryptErrorHasGPGReason(t *testing.T) {
-	// The empty GNUPGHOME keeps gpg away from the user's own keyring;
-	// LC_ALL=C keeps gpg's message in English.
-	t.Setenv("GNUPGHOME", t.TempDir())
-	t.Setenv("LC_ALL", "C")
-
-	_, err := secret.GPGDecryptFunc([]byte("not an OpenPGP message"))
-	require.ErrorContains(t, err, "gpg: no valid OpenPGP data found")
-}
-
-// TestGPGDecryptErrorWithoutGPGStderr checks that when gpg fails without
-// writing to stderr, the error ends with the exit status and nothing after it.
-//
-//nolint:paralleltest // installFakeGPG uses t.Setenv
-func TestGPGDecryptErrorWithoutGPGStderr(t *testing.T) {
-	installFakeGPG(t)
-
-	_, err := secret.GPGDecryptFunc([]byte("not an OpenPGP message"))
-	require.EqualError(t, err, "GPG decryption failed: exit status 1")
-}