Refuse to create a vault that already exists (closes #74)

vault.CreateVault now checks for the vault before writing anything and
fails with "vault NAME already exists" (vault.ErrVaultExists). secret
init and secret vault create call it while holding the state directory
lock, so two creates at once cannot both pass the check. Before, either
command over an existing vault replaced its metadata, passphrase
unlocker and longterm.age, so none of its secrets could be decrypted.

Both commands now ask for the unlocker passphrase before creating the
vault, so one stopped at that prompt leaves no vault without an
unlocker behind, which they would then refuse to create again.

The lock tests set up the vault "work" instead of "default", which init
now refuses to create again.

Model: opus-5-5

internal/cli/create_vault_test.go

@@ -0,0 +1,148 @@
+package cli_test
+
+import (
+	"testing"
+
+	"git.eeqj.de/sneak/secret/internal/cli"
+	"git.eeqj.de/sneak/secret/internal/secret"
+	"git.eeqj.de/sneak/secret/internal/vault"
+	"github.com/awnumar/memguard"
+	"github.com/spf13/afero"
+	"github.com/spf13/cobra"
+	"github.com/stretchr/testify/require"
+)
+
+// TestCreateExistingVaultChangesNothing is a regression test for
+// https://git.eeqj.de/sneak/secret/issues/74, where running `secret init`
+// a second time, or `secret vault create` with the name of an existing
+// vault, replaced that vault's keys, so that none of its secrets could be
+// decrypted any more. Each must refuse, change nothing, and leave every
+// vault's secret readable through its passphrase unlocker.
+//
+//nolint:paralleltest // t.Setenv forbids parallel subtests
+func TestCreateExistingVaultChangesNothing(t *testing.T) {
+	t.Setenv(secret.EnvMnemonic, testMnemonic)
+	t.Setenv(secret.EnvUnlockPassphrase, testPassphrase)
+
+	// `secret init`, `secret vault create work`, `secret vault select
+	// default`, and the secret "x" in each vault. "work" is then not the
+	// current vault, which creating it again must not change.
+	fs := afero.NewMemMapFs()
+	c := cli.NewCLIInstanceWithStateDir(fs, testStateDir)
+	cmd := &cobra.Command{}
+
+	require.NoError(t, c.Init(cmd))
+	require.NoError(t, c.CreateVault(cmd, "work"))
+	require.NoError(t, c.SelectVault(cmd, "default"))
+
+	vaults, err := vault.ListVaults(fs, testStateDir)
+	require.NoError(t, err)
+	require.Len(t, vaults, 2)
+
+	for _, name := range vaults {
+		value := memguard.NewBufferFromBytes([]byte("value"))
+		err := vault.NewVault(fs, testStateDir, name).AddSecret("x", value, false)
+		require.NoError(t, err)
+	}
+
+	before := snapshotStateDir(t, fs)
+
+	tests := []struct {
+		command string
+		want    string
+		run     func(c *cli.Instance) error
+	}{
+		{
+			"init",
+			"failed to create default vault: vault default already exists",
+			func(c *cli.Instance) error { return c.Init(cmd) },
+		},
+		{
+			"vault create default",
+			"vault default already exists",
+			func(c *cli.Instance) error { return c.CreateVault(cmd, "default") },
+		},
+		{
+			"vault create work",
+			"vault work already exists",
+			func(c *cli.Instance) error { return c.CreateVault(cmd, "work") },
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.command, func(t *testing.T) {
+			fs := newFsFromSnapshot(t, before)
+
+			err := tt.run(cli.NewCLIInstanceWithStateDir(fs, testStateDir))
+
+			require.EqualError(t, err, tt.want)
+			require.Equal(t, before, snapshotStateDir(t, fs))
+		})
+	}
+
+	// Every case left the state directory exactly as recorded in before, so
+	// reading each vault's secret once from it shows that it still decrypts
+	// after each case. Without the mnemonic, reading a secret goes through
+	// the vault's passphrase unlocker, which is slow.
+	t.Setenv(secret.EnvMnemonic, "")
+
+	for _, name := range vaults {
+		value, err := vault.NewVault(fs, testStateDir, name).GetSecret("x")
+		require.NoError(t, err)
+		require.Equal(t, "value", string(value))
+	}
+}
+
+// TestStopAtPassphrasePromptLeavesNothing is a regression test for the
+// review of https://git.eeqj.de/sneak/secret/pulls/82: `secret init` or
+// `secret vault create` stopped at the passphrase prompt left a vault with
+// no unlocker, which neither command would then create again. Each must ask
+// for the passphrase before writing anything.
+//
+//nolint:paralleltest // t.Setenv forbids parallel subtests
+func TestStopAtPassphrasePromptLeavesNothing(t *testing.T) {
+	t.Setenv(secret.EnvMnemonic, testMnemonic)
+
+	// Without the passphrase in the environment, both commands prompt for
+	// it, which fails because the tests do not run in a terminal.
+	t.Setenv(secret.EnvUnlockPassphrase, "")
+
+	// An empty state directory for `secret init`, and one holding the vault
+	// "default" for `secret vault create work`.
+	empty := afero.NewMemMapFs()
+	require.NoError(t, empty.MkdirAll(testStateDir, secret.DirPerms))
+
+	withDefault := afero.NewMemMapFs()
+	_, err := vault.CreateVault(withDefault, testStateDir, "default")
+	require.NoError(t, err)
+
+	cmd := &cobra.Command{}
+
+	tests := []struct {
+		command string
+		fs      afero.Fs
+		run     func(c *cli.Instance) error
+	}{
+		{
+			"init",
+			empty,
+			func(c *cli.Instance) error { return c.Init(cmd) },
+		},
+		{
+			"vault create work",
+			withDefault,
+			func(c *cli.Instance) error { return c.CreateVault(cmd, "work") },
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.command, func(t *testing.T) {
+			before := snapshotStateDir(t, tt.fs)
+
+			err := tt.run(cli.NewCLIInstanceWithStateDir(tt.fs, testStateDir))
+
+			require.ErrorContains(t, err, "failed to read passphrase")
+			require.Equal(t, before, snapshotStateDir(t, tt.fs))
+		})
+	}
+}

internal/cli/init.go

@@ -160,6 +160,14 @@ func (cli *Instance) initialize(cmd *cobra.Command) error {
 			errInvalidMnemonicPhrase)
 	}
 
+	// Ask for the unlocker passphrase before creating the vault, so that
+	// stopping at the prompt leaves no vault without an unlocker behind
+	passphraseBuffer, err := resolvePassphrase()
+	if err != nil {
+		return err
+	}
+	defer passphraseBuffer.Destroy()
+
 	// Set mnemonic in environment for CreateVault to use
 	restoreMnemonicEnv := setMnemonicEnv(mnemonicStr)
 	defer restoreMnemonicEnv()
@@ -175,13 +183,6 @@ func (cli *Instance) initialize(cmd *cobra.Command) error {
 	// Unlock the vault with the derived long-term key
 	vlt.Unlock(ltIdentity)
 
-	// Prompt for passphrase for unlocker
-	passphraseBuffer, err := resolvePassphrase()
-	if err != nil {
-		return err
-	}
-	defer passphraseBuffer.Destroy()
-
 	// Create passphrase-protected unlocker
 	secret.Debug("Creating passphrase-protected unlocker")
 

internal/cli/lock_test.go

@@ -274,11 +274,12 @@ func stateDirModTimes(t *testing.T, fs afero.Fs) map[string]int64 {
 }
 
 // setupEveryCommand makes what each command in
-// TestChangingCommandsWaitForLock needs: the current vault "default" with
-// two versions of "test/secret", the vault "other" without a long-term key,
-// for vault import, and the file testInput. If withUnlocker is set, it also
-// gives "default" a passphrase unlocker, which is slow. It returns the older
-// version and the unlocker's ID.
+// TestChangingCommandsWaitForLock needs: the current vault "work" with two
+// versions of "test/secret", the vault "other" without a long-term key, for
+// vault import, and the file testInput. There is no vault "default", which
+// init creates. If withUnlocker is set, it also gives "work" a passphrase
+// unlocker, which is slow. It returns the older version and the unlocker's
+// ID.
 func setupEveryCommand(
 	t *testing.T, fs afero.Fs, withUnlocker bool,
 ) (string, string) {
@@ -291,7 +292,7 @@ func setupEveryCommand(
 	require.NoError(t, err)
 	require.NoError(t, fs.Remove(filepath.Join(otherDir, "pub.age")))
 
-	vlt, err := vault.CreateVault(fs, testStateDir, "default")
+	vlt, err := vault.CreateVault(fs, testStateDir, "work")
 	require.NoError(t, err)
 
 	addTestSecret(t, vlt, []byte("older"), false)

internal/cli/vault.go

@@ -309,6 +309,14 @@ func (cli *Instance) CreateVault(cmd *cobra.Command, name string) error {
 		return errInvalidMnemonicPhrase
 	}
 
+	// Ask for the unlocker passphrase before creating the vault, so that
+	// stopping at the prompt leaves no vault without an unlocker behind
+	passphraseBuffer, err := resolvePassphrase()
+	if err != nil {
+		return err
+	}
+	defer passphraseBuffer.Destroy()
+
 	// Set mnemonic in environment for CreateVault to use
 	restoreMnemonicEnv := setMnemonicEnv(mnemonicStr)
 	defer restoreMnemonicEnv()
@@ -336,13 +344,6 @@ func (cli *Instance) CreateVault(cmd *cobra.Command, name string) error {
 	// Unlock the vault with the derived long-term key
 	vlt.Unlock(ltIdentity)
 
-	// Get or prompt for passphrase
-	passphraseBuffer, err := resolvePassphrase()
-	if err != nil {
-		return err
-	}
-	defer passphraseBuffer.Destroy()
-
 	// Create passphrase-protected unlocker
 	secret.Debug("Creating passphrase-protected unlocker")