A cross-vault secret mv that cannot remove the source fails (closes #159)

When `secret mv` copied a secret into another vault but could not remove
the source, it printed a warning and the usual "Moved" line and exited 0,
so a script could not tell that the secret was now in both vaults. It now
prints no "Moved" line and fails with an error saying that the copy holds
all versions and the source remains.

The test is in package cli and calls moveSecret, because the state
directory lock refuses the wrapped filesystem that makes the removal fail.

Judgement call: if the source is moved aside but the temporary directory
holding it cannot then be deleted, the error still says the source remains.

Model: opus-5-5

README.md

@@ -271,6 +271,12 @@ Creates a new unlocker of the specified type:
 A vault has one passphrase unlocker: adding one replaces the one the vault has,
 which is removed only once the new one is the current unlocker.
 
+`secret unlocker add passphrase` asks on the terminal for the new passphrase
+even when `SB_UNLOCK_PASSPHRASE` is set, and uses the variable to unlock the
+vault. With no controlling terminal, as under cron or in a CI job, the new
+unlocker takes its passphrase from `SB_UNLOCK_PASSPHRASE`, and the command says
+so.
+
 #### `secret unlocker remove <unlocker-id> [--force]` / `secret unlocker rm` ⚠️ 🛑
 
 **DANGER**: Permanently removes an unlocker. It first asks for confirmation,
@@ -554,7 +560,11 @@ secret decrypt encryption/mykey --input document.txt.age --output document.txt
 ### Vault Management
 
 - **Derivation Index**: Each vault uses a unique derivation index from the
-  mnemonic, and thus a unique key pair
+  mnemonic, and thus a unique key pair; creating a vault (`secret init` and
+  `secret vault create`) fails, with an error naming the file, when any vault's
+  `vault-metadata.json` exists but cannot be read or parsed; a vault directory
+  with no `vault-metadata.json` is skipped, so the index it uses can be given to
+  a new vault
 - **Public Key Hash**: Double SHA-256 hash of the vault's public key; the same
   hash of the index-0 public key identifies vaults from the same mnemonic
 - **Automatic Key Derivation**: When creating vaults with a mnemonic, keys are

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
+// long-term key. The command is gone, so it fails as any subcommand of
-// `secret vault`, as it does any subcommand of `secret vault` it does not
+// `secret vault` that does not exist does.
-// know.
 func TestNoVaultImportCommand(t *testing.T) {
 	t.Setenv(secret.EnvStateDir, t.TempDir())
-
-	run := func(args ...string) string {
 	t.Setenv(secret.EnvMnemonic, testMnemonic)
 	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
 
-		output, err := cli.ExecuteCommandInProcess(args, "", nil)
+	_, err := cli.ExecuteCommandInProcess(
-		require.NoError(t, err, "%v", args)
+		strings.Fields("vault create work"), "", nil)
+	require.NoError(t, err)
 
-		return output
+	_, err = cli.ExecuteCommandInProcess(
-	}
+		strings.Fields("vault import work"), "", nil)
-
+	require.EqualError(t, err, `unknown command "import" for "secret vault"`)
-	run("vault", "create", "work")
-
-	require.Equal(t, run("vault"), run("vault", "import", "work"))
 }
 
 // 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/move_cross_vault_test.go

@@ -0,0 +1,85 @@
+//nolint:testpackage // white-box test of unexported internals
+package cli
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/awnumar/memguard"
+	"github.com/spf13/afero"
+	"github.com/spf13/cobra"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/secret/internal/vault"
+)
+
+// errRenameFailed is returned by renameFailFs in place of a successful
+// rename.
+var errRenameFailed = errors.New("permission denied")
+
+// renameFailFs fails every Rename of one path, as a read-only parent
+// directory does.
+type renameFailFs struct {
+	afero.Fs
+
+	path string
+}
+
+func (f *renameFailFs) Rename(oldname, newname string) error {
+	if oldname == f.path {
+		return errRenameFailed
+	}
+
+	return f.Fs.Rename(oldname, newname)
+}
+
+// TestCrossVaultMoveFailsWhenSourceRemains is a regression test for
+// https://git.eeqj.de/sneak/secret/issues/159, where a move between two
+// vaults whose source could not be removed reported the secret moved and
+// succeeded. It must fail, and the copy and the source must both be there.
+// The state directory lock refuses the wrapped filesystem, so the test
+// calls moveSecret, which MoveSecret runs once it holds the lock.
+func TestCrossVaultMoveFailsWhenSourceRemains(t *testing.T) {
+	t.Parallel()
+
+	base := afero.NewMemMapFs()
+
+	_, err := vault.CreateVault(base, testStateDir, "work",
+		testMnemonicBuffer(t), nil)
+	require.NoError(t, err)
+
+	source, err := vault.CreateVault(base, testStateDir, "default",
+		testMnemonicBuffer(t), nil)
+	require.NoError(t, err)
+
+	err = source.AddSecret("x",
+		memguard.NewBufferFromBytes([]byte("value")), false)
+	require.NoError(t, err)
+
+	instance := NewCLIInstanceWithStateDir(&renameFailFs{
+		Fs:   base,
+		path: testStateDir + "/vaults.d/default/secrets.d/x",
+	}, testStateDir)
+	instance.Mnemonic = testMnemonicBuffer(t)
+
+	err = instance.moveSecret(&cobra.Command{}, "default:x", "work:y", false)
+	require.ErrorIs(t, err, errRenameFailed)
+	require.ErrorContains(t, err, "secret 'default:x' is copied with all "+
+		"1 version(s) to 'work:y', but the source remains")
+
+	// requireValue requires that the vault vaultName holds secretName with
+	// the value stored above.
+	requireValue := func(vaultName, secretName string) {
+		vlt := vault.NewVault(base, testStateDir, vaultName)
+		vlt.Mnemonic = testMnemonicBuffer(t)
+
+		value, err := vlt.GetSecret(secretName)
+		require.NoError(t, err, vaultName+":"+secretName)
+
+		defer value.Destroy()
+
+		require.Equal(t, []byte("value"), value.Bytes())
+	}
+
+	requireValue("default", "x")
+	requireValue("work", "y")
+}

internal/cli/passphrase_prompt_test.go

@@ -138,6 +138,148 @@ func TestInitWritesNoBlankLineAfterMnemonic(t *testing.T) {
 		"stderr: %q", stderr.String())
 }
 
+// TestUnlockerAddAsksForNewPassphrase is a regression test for
+// https://git.eeqj.de/sneak/secret/issues/154: with SB_UNLOCK_PASSPHRASE set,
+// `secret unlocker add passphrase` gave the new unlocker the passphrase in
+// the variable without asking. At a terminal it must ask for the new
+// passphrase there, twice, and unlock the vault with the variable, so that
+// `secret get` then opens the vault with the passphrase typed. pty.Open is
+// described above TestRemoveIgnoresTerminalOnStdout.
+func TestUnlockerAddAsksForNewPassphrase(t *testing.T) {
+	t.Parallel()
+
+	const newPassphrase = "new-passphrase"
+
+	stateDir := t.TempDir()
+
+	passphrase := memguard.NewBufferFromBytes([]byte(testPassphrase))
+	defer passphrase.Destroy()
+
+	vlt, err := vault.CreateVault(afero.NewOsFs(), stateDir, "default",
+		testMnemonicBuffer(t), passphrase)
+	require.NoError(t, err)
+
+	value := memguard.NewBufferFromBytes([]byte("v1"))
+	defer value.Destroy()
+
+	require.NoError(t, vlt.AddSecret("s1", value, false))
+
+	ctx, cancel := context.WithTimeout(t.Context(), commandWait)
+	defer cancel()
+
+	//nolint:gosec // G204: test executes the freshly built secret binary
+	cmd := exec.CommandContext(ctx, secretBinaryPath(t),
+		"unlocker", "add", "passphrase")
+	cmd.Env = []string{
+		secret.EnvStateDir + "=" + stateDir,
+		secret.EnvUnlockPassphrase + "=" + testPassphrase,
+		"PATH=" + os.Getenv("PATH"),
+		"HOME=" + os.Getenv("HOME"),
+	}
+
+	ptmx, tty, err := pty.Open()
+	require.NoError(t, err)
+
+	defer func() { _ = ptmx.Close() }()
+
+	deadline, _ := ctx.Deadline()
+	require.NoError(t, ptmx.SetReadDeadline(deadline))
+
+	cmd.Stderr = tty
+	// Ctty is a descriptor in the new process: 2, its stderr.
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setsid: true, Setctty: true, Ctty: 2}
+
+	require.NoError(t, cmd.Start())
+
+	_ = tty.Close()
+
+	var (
+		shown []byte
+		char  byte
+	)
+
+	terminal := bufio.NewReader(ptmx)
+
+	for _, prompt := range []string{
+		"Enter passphrase for unlocker: ", "Confirm passphrase: ",
+	} {
+		for !bytes.HasSuffix(shown, []byte(prompt)) {
+			char, err = terminal.ReadByte()
+			require.NoError(t, err,
+				"secret unlocker add passphrase did not ask on the terminal: %s",
+				shown)
+
+			shown = append(shown, char)
+		}
+
+		_, err = ptmx.WriteString(newPassphrase + "\n")
+		require.NoError(t, err)
+	}
+
+	// The read ends once the command has exited and so closed the terminal.
+	rest, _ := io.ReadAll(terminal)
+
+	require.NoError(t, cmd.Wait(),
+		"secret unlocker add passphrase: %s%s", shown, rest)
+
+	// The binary, not this test process, opens the vault: the new unlocker
+	// has age's full scrypt work factor, which is slow under the race
+	// detector.
+	assert.Equal(t, "v1",
+		runWithoutTerminal(t, stateDir, newPassphrase, "get", "s1"))
+}
+
+// TestUnlockerAddWithoutTerminalSaysPassphraseIsVariable is a regression
+// test for https://git.eeqj.de/sneak/secret/issues/154: with no terminal to
+// ask on, `secret unlocker add passphrase` gives the new unlocker the
+// passphrase in SB_UNLOCK_PASSPHRASE, and its output must say so.
+func TestUnlockerAddWithoutTerminalSaysPassphraseIsVariable(t *testing.T) {
+	t.Parallel()
+
+	stateDir := t.TempDir()
+
+	passphrase := memguard.NewBufferFromBytes([]byte(testPassphrase))
+	defer passphrase.Destroy()
+
+	_, err := vault.CreateVault(afero.NewOsFs(), stateDir, "default",
+		testMnemonicBuffer(t), passphrase)
+	require.NoError(t, err)
+
+	output := runWithoutTerminal(t, stateDir, testPassphrase,
+		"unlocker", "add", "passphrase")
+
+	assert.Contains(t, output, "The new unlocker takes its passphrase "+
+		"from SB_UNLOCK_PASSPHRASE, since there is no terminal to ask for a "+
+		"new one on\n")
+}
+
+// runWithoutTerminal runs the secret binary with args and SB_UNLOCK_PASSPHRASE
+// set to passphrase, in a new session, which has no terminal, and returns
+// what it printed once it has succeeded.
+func runWithoutTerminal(
+	t *testing.T, stateDir, passphrase string, args ...string,
+) string {
+	t.Helper()
+
+	ctx, cancel := context.WithTimeout(t.Context(), commandWait)
+	defer cancel()
+
+	//nolint:gosec // G204: test executes the freshly built secret binary
+	cmd := exec.CommandContext(ctx, secretBinaryPath(t), args...)
+	cmd.Env = []string{
+		secret.EnvStateDir + "=" + stateDir,
+		secret.EnvUnlockPassphrase + "=" + passphrase,
+		"PATH=" + os.Getenv("PATH"),
+		"HOME=" + os.Getenv("HOME"),
+	}
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setsid: true}
+
+	output, err := cmd.CombinedOutput()
+	require.NoError(t, err, "secret %v: %s", args, output)
+
+	return string(output)
+}
+
 // runAtTerminal runs the secret binary with args and input on stdin, in a
 // new session whose controlling terminal is a new terminal, which is also
 // its stderr: a command typed at a terminal with its input piped. pty.Open

internal/cli/secrets.go

@@ -1097,12 +1097,10 @@ func (cli *Instance) moveSecretCrossVault(
 	// Delete source secret
 	err = secret.RemoveDirAtomic(cli.fs, srcSecretDir)
 	if err != nil {
-		// Copy succeeded but delete failed - warn but don't fail
+		return fmt.Errorf("secret '%s:%s' is copied with all %d version(s) "+
-		cmd.Printf("Warning: copied secret but failed to remove source: %v\n", err)
+			"to '%s:%s', but the source remains: %w",
-		cmd.Printf("Moved secret '%s:%s' to '%s:%s' (%d version(s))\n",
+			srcVault.Name, srcSecretName, versionCount,
-			srcVault.Name, srcSecretName, destVault.Name, destSecretName, versionCount)
+			destVault.Name, destSecretName, err)
-
-		return nil
 	}
 
 	cmd.Printf("Moved secret '%s:%s' to '%s:%s' (%d version(s))\n",

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())
@@ -441,15 +447,20 @@ func (cli *Instance) addPassphraseUnlocker(cmd *cobra.Command) error {
 	// long-term key
 	vlt.Mnemonic, vlt.UnlockPassphrase = cli.Mnemonic, cli.UnlockPassphrase
 
-	// The new unlocker gets the passphrase from the environment, which also
+	// The new passphrase is asked for even when SB_UNLOCK_PASSPHRASE is
-	// unlocks the current passphrase unlocker, else the one entered here
+	// set, and the variable unlocks the vault. With no terminal to ask on,
-	passphraseBuffer := cli.UnlockPassphrase
+	// the new unlocker takes the passphrase in the variable.
-	if passphraseBuffer == nil {
+	fromVariable := false
-		// Use secure passphrase input with confirmation
+
-		passphraseBuffer, err = readSecurePassphrase("Enter passphrase for unlocker: ")
+	passphraseBuffer, err := readSecurePassphrase("Enter passphrase for unlocker: ")
-		if err != nil {
+
+	switch {
+	case errors.Is(err, secret.ErrNoTerminal) && cli.UnlockPassphrase != nil:
+		passphraseBuffer = cli.UnlockPassphrase
+		fromVariable = true
+	case err != nil:
 		return err
-		}
+	default:
 		defer passphraseBuffer.Destroy()
 	}
 
@@ -460,6 +471,12 @@ func (cli *Instance) addPassphraseUnlocker(cmd *cobra.Command) error {
 
 	cmd.Printf("Created passphrase unlocker: %s\n", passphraseUnlocker.GetID())
 
+	if fromVariable {
+		cmd.Printf("The new unlocker takes its passphrase from %s, since "+
+			"there is no terminal to ask for a new one on\n",
+			secret.EnvUnlockPassphrase)
+	}
+
 	// CreatePassphraseUnlocker has already made it the current unlocker
 	cmd.Printf("Automatically selected as current unlocker\n")
 

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/crypto.go

@@ -15,10 +15,13 @@ import (
 
 var (
 	errNilPassphraseBuffer = errors.New("passphrase buffer is nil")
-	errNoTerminal          = errors.New("there is no terminal to ask on")
 	errNothingEntered      = errors.New("nothing was entered")
 )
 
+// ErrNoTerminal is wrapped in the error of ReadPassphrase and ReadMnemonic
+// when the process has no controlling terminal to ask on.
+var ErrNoTerminal = errors.New("there is no terminal to ask on")
+
 // ErrMnemonicNotRead is wrapped in every error of ReadMnemonic: there is no
 // terminal to read the mnemonic from, reading it failed, or it was empty.
 var ErrMnemonicNotRead = errors.New("failed to read mnemonic")
@@ -203,7 +206,7 @@ func readFromTerminal(
 
 		return nil, fmt.Errorf(
 			"%w: %w. Please set the %s environment variable or run interactively",
-			notRead, errNoTerminal, envVar)
+			notRead, ErrNoTerminal, envVar)
 	}
 	defer func() { _ = terminal.Close() }()
 

internal/vault/metadata.go

@@ -4,7 +4,9 @@ import (
 	"crypto/sha256"
 	"encoding/hex"
 	"encoding/json"
+	"errors"
 	"fmt"
+	"os"
 	"path/filepath"
 
 	"github.com/spf13/afero"
@@ -33,7 +35,10 @@ func ComputeDoubleSHA256(data []byte) string {
 }
 
 // GetNextDerivationIndex finds the next available derivation index for a given mnemonic
-// by deriving the public key for index 0 and using its hash to identify related vaults
+// by deriving the public key for index 0 and using its hash to identify related vaults.
+// It fails when a vault's metadata file exists but cannot be read or parsed: the
+// index that vault uses is then unknown, and handing it out again would give a
+// second vault the same long-term key.
 func GetNextDerivationIndex(
 	fs afero.Fs, stateDir string, mnemonic string,
 ) (uint32, error) {
@@ -72,21 +77,23 @@ func GetNextDerivationIndex(
 			continue
 		}
 
-		// Try to read vault metadata
 		metadataPath := filepath.Join(vaultsDir, entry.Name(), "vault-metadata.json")
 
 		metadataBytes, err := afero.ReadFile(fs, metadataPath)
-		if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
-			// Skip vaults without metadata
+			// Skip directories without metadata
 			continue
 		}
 
+		if err != nil {
+			return 0, fmt.Errorf("failed to read vault metadata %s: %w", metadataPath, err)
+		}
+
 		var metadata Metadata
 
 		err = json.Unmarshal(metadataBytes, &metadata)
 		if err != nil {
-			// Skip vaults with invalid metadata
+			return 0, fmt.Errorf("failed to parse vault metadata %s: %w", metadataPath, err)
-			continue
 		}
 
 		// Check if this vault uses the same mnemonic by comparing family hashes

internal/vault/metadata_test.go

@@ -1,11 +1,15 @@
 package vault_test
 
 import (
+	"errors"
 	"path/filepath"
 	"strings"
 	"testing"
 
 	"github.com/spf13/afero"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/secret/internal/secret"
 	"sneak.berlin/go/secret/internal/vault"
 	"sneak.berlin/go/secret/pkg/agehd"
 )
@@ -163,6 +167,88 @@ func testGetNextDerivationIndex(t *testing.T, fs afero.Fs) {
 	}
 }
 
+// errMetadataUnreadable is returned by the test filesystem in place of a
+// successful open of one vault's metadata file.
+var errMetadataUnreadable = errors.New("input/output error")
+
+// metadataReadFailFs fails every open of the file at unreadablePath. The
+// file still exists, so checking for it succeeds and only reading it fails.
+type metadataReadFailFs struct {
+	afero.Fs
+
+	unreadablePath string
+}
+
+//nolint:ireturn // afero.File is the interface required by afero.Fs
+func (f *metadataReadFailFs) Open(name string) (afero.File, error) {
+	if name == f.unreadablePath {
+		return nil, errMetadataUnreadable
+	}
+
+	return f.Fs.Open(name)
+}
+
+// TestCreateVaultWithCorruptMetadataFails checks that creating a vault from
+// a mnemonic fails, naming the file and leaving no new vault, when another
+// vault's metadata file exists but cannot be parsed or read. That vault's
+// derivation index is then unknown, so the new vault could get the same one
+// and the same key.
+func TestCreateVaultWithCorruptMetadataFails(t *testing.T) {
+	t.Parallel()
+
+	vaultsDir := filepath.Join(testStateDir, "vaults.d")
+	metadataPath := filepath.Join(vaultsDir, "work", "vault-metadata.json")
+
+	tests := []struct {
+		name string
+		// breakMetadata makes the work vault's metadata file unusable on
+		// base and returns the filesystem to create the second vault on.
+		breakMetadata func(t *testing.T, base afero.Fs) afero.Fs
+	}{
+		{
+			name: "parsing the file fails",
+			breakMetadata: func(t *testing.T, base afero.Fs) afero.Fs {
+				t.Helper()
+
+				err := afero.WriteFile(base, metadataPath, []byte("{"),
+					secret.FilePerms)
+				require.NoError(t, err)
+
+				return base
+			},
+		},
+		{
+			name: "reading the file fails",
+			breakMetadata: func(_ *testing.T, base afero.Fs) afero.Fs {
+				return &metadataReadFailFs{Fs: base, unreadablePath: metadataPath}
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			base := afero.NewMemMapFs()
+
+			_, err := vault.CreateVault(base, testStateDir, "work",
+				testMnemonicBuffer(t), nil)
+			require.NoError(t, err)
+
+			fs := tt.breakMetadata(t, base)
+
+			_, err = vault.CreateVault(fs, testStateDir, "other",
+				testMnemonicBuffer(t), nil)
+			require.ErrorContains(t, err, metadataPath)
+
+			entries, err := afero.ReadDir(base, vaultsDir)
+			require.NoError(t, err)
+			require.Len(t, entries, 1)
+			assert.Equal(t, "work", entries[0].Name())
+		})
+	}
+}
+
 func testMetadataPersistence(t *testing.T, fs afero.Fs) {
 	t.Helper()