Give each failure one error value (closes #113)

internal/cli's copies of vault.ErrSecretNotFound, ErrVaultNotFound,
ErrVersionNotFound and ErrSecretExists are removed; the commands wrap the
vault errors. errUnsupportedUnlockerType is removed for
errInvalidUnlockerType, which names the same failure. Every error of
secret.ReadPassphrase wraps ErrPassphraseNotRead, so its callers no longer
add those words. ResolveGPGKeyFingerprint returns ErrGPGKeyNotFound for a
key the keyring lacks, recognised by gpg's status line. storeInKeychain
returns errNilDataBuffer. bip85's ErrPasswordTooShort and
ErrEncodedTooShort go with their unreachable checks. Tests that matched
these errors' text use errors.Is.

Model: opus-5-5

TODO.md

@@ -18,6 +18,29 @@ https://git.eeqj.de/sneak/secret/milestone/12
 
 # Completed Steps
 
+- 2026-10-04: A failure returns the same error value whichever command hits
+  it (https://git.eeqj.de/sneak/secret/issues/113). `internal/cli` no longer
+  keeps its own copies of `vault.ErrSecretNotFound`, `ErrVaultNotFound`,
+  `ErrVersionNotFound` and `ErrSecretExists`: `secret mv`, `rm`, `decrypt`,
+  `vault import`, `vault remove` and `version list`, `promote` and `rm` wrap
+  the `vault` errors. `errUnsupportedUnlockerType` is removed: `secret
+  unlocker add` gives `errInvalidUnlockerType` for an unknown type, whichever
+  check rejects it. Messages are unchanged, except that `secret decrypt`
+  of a missing secret says "not found", as `secret get` does, not "does not
+  exist". Every error of `secret.ReadPassphrase` wraps
+  `secret.ErrPassphraseNotRead`, which supplies the words "failed to read
+  passphrase" that its callers used to add themselves; so two passphrases
+  that differ now give only "passphrases do not match", the words now follow
+  "failed to read mnemonic:" and "failed to read passphrase confirmation:",
+  and a terminal read error no longer repeats them. A GPG key the keyring
+  does not hold gives `secret.ErrGPGKeyNotFound`, found by gpg's status line
+  for "No public key"; before, the message repeated "failed to resolve GPG
+  key fingerprint" and ended in gpg's exit status. The keychain unlocker
+  returns `errNilDataBuffer` for nil data; this and its test build only on
+  macOS with cgo and were only read. `bip85.ErrPasswordTooShort` and
+  `ErrEncodedTooShort` are removed with their checks: 64 bytes of entropy
+  always give 86 Base64 or 80 Base85 characters, the most a password length
+  may ask for. Tests that matched these errors' text use `errors.Is`.
 - 2026-10-04: Tests check which error a failure returns with `errors.Is`,
   not by matching words of its message
   (https://git.eeqj.de/sneak/secret/issues/49). Every exported error that

internal/cli/create_vault_test.go

@@ -188,7 +188,7 @@ func TestStopAtPassphrasePromptLeavesNothing(t *testing.T) {
 
 			err := tt.run(c)
 
-			require.ErrorContains(t, err, "failed to read passphrase")
+			require.ErrorIs(t, err, secret.ErrPassphraseNotRead)
 			require.Equal(t, before, snapshotStateDir(t, tt.fs))
 		})
 	}

internal/cli/crypto.go

@@ -17,7 +17,6 @@ import (
 var (
 	errNotAgeSecretKey = errors.New(
 		"does not contain a valid age secret key")
-	errSecretDoesNotExist = errors.New("does not exist")
 )
 
 // newCryptoCmd builds an encrypt/decrypt command with input/output flags
@@ -245,7 +244,7 @@ func (cli *Instance) Decrypt(secretName, inputFile, outputFile string) error {
 	}
 
 	if !exists {
-		return fmt.Errorf("secret '%s' %w", secretName, errSecretDoesNotExist)
+		return fmt.Errorf("secret '%s' %w", secretName, vault.ErrSecretNotFound)
 	}
 
 	// Get the age secret key from the secret

internal/cli/errors_test.go

@@ -0,0 +1,62 @@
+package cli_test
+
+import (
+	"testing"
+
+	"git.eeqj.de/sneak/secret/internal/cli"
+	"git.eeqj.de/sneak/secret/internal/vault"
+	"github.com/spf13/cobra"
+)
+
+// TestMissingSecretOrVaultErrors checks that a command that finds no such
+// secret or vault returns the vault package's error for it, as `secret get`
+// does, and leaves the vaults unchanged. "default" is the current vault, and
+// both vaults hold the secret "x".
+func TestMissingSecretOrVaultErrors(t *testing.T) {
+	t.Parallel()
+
+	before := snapshotStateDir(t, newTwoVaultFs(t))
+
+	tests := []struct {
+		command string
+		want    error
+		run     func(c *cli.Instance) error
+	}{
+		{
+			"rm --force nosuch", vault.ErrSecretNotFound,
+			func(c *cli.Instance) error {
+				return c.RemoveSecret(&cobra.Command{}, "nosuch", true)
+			},
+		},
+		{
+			"version rm --force nosuch", vault.ErrSecretNotFound,
+			func(c *cli.Instance) error {
+				return c.RemoveVersion(&cobra.Command{}, "nosuch", "20260101.001", true)
+			},
+		},
+		{
+			"mv --force work:nosuch default", vault.ErrSecretNotFound,
+			func(c *cli.Instance) error {
+				return c.MoveSecret(&cobra.Command{}, "work:nosuch", "default", true)
+			},
+		},
+		{
+			"decrypt nosuch", vault.ErrSecretNotFound,
+			func(c *cli.Instance) error { return c.Decrypt("nosuch", "", "") },
+		},
+		{
+			"vault rm --force nosuch", vault.ErrVaultNotFound,
+			func(c *cli.Instance) error {
+				return c.RemoveVault(&cobra.Command{}, "nosuch", true)
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.command, func(t *testing.T) {
+			t.Parallel()
+
+			requireRejectedAndUnchanged(t, before, tt.want, tt.run)
+		})
+	}
+}

internal/cli/integration_test.go

@@ -1216,9 +1216,8 @@ func test12bMoveSecret(t *testing.T, testMnemonic string, runSecret func(...stri
 
 	// Test error cases
 	// Try to move non-existent secret
-	output, err = runSecret("move", "test/nonexistent", "test/destination")
-	require.Error(t, err, "move non-existent should fail")
-	assert.Contains(t, output, "not found", "should indicate source not found")
+	_, err = runSecret("move", "test/nonexistent", "test/destination")
+	require.ErrorIs(t, err, vault.ErrSecretNotFound, "move non-existent should fail")
 
 	// Try to move to existing destination
 	_, err = runSecretWithStdin("dest-value", map[string]string{
@@ -1226,9 +1225,8 @@ func test12bMoveSecret(t *testing.T, testMnemonic string, runSecret func(...stri
 	}, "add", "test/existing-dest")
 	require.NoError(t, err, "add test/existing-dest should succeed")
 
-	output, err = runSecret("move", "test/renamed", "test/existing-dest")
-	require.Error(t, err, "move to existing destination should fail")
-	assert.Contains(t, output, "already exists", "should indicate destination exists")
+	_, err = runSecret("move", "test/renamed", "test/existing-dest")
+	require.ErrorIs(t, err, vault.ErrSecretExists, "move to existing destination should fail")
 
 	// Verify the source wasn't removed since move failed
 	getOutput, err = runSecretWithEnv(map[string]string{
@@ -1933,12 +1931,11 @@ func test23ErrorHandling(t *testing.T, tempDir, secretPath, testMnemonic string,
 
 	// Import to non-existent vault with test passphrase
 	testPassphrase := "test-passphrase-123" // Define testPassphrase locally
-	output, err := runSecretWithEnv(map[string]string{
+	_, err = runSecretWithEnv(map[string]string{
 		secret.EnvMnemonic:         testMnemonic,
 		secret.EnvUnlockPassphrase: testPassphrase,
 	}, "vault", "import", "nonexistent")
-	require.Error(t, err, "import to non-existent vault should fail")
-	assert.Contains(t, output, "does not exist", "should indicate vault doesn't exist")
+	require.ErrorIs(t, err, vault.ErrVaultNotFound, "import to non-existent vault should fail")
 
 	// Get specific version that doesn't exist
 	_, err = runSecretWithEnv(map[string]string{
@@ -1947,11 +1944,10 @@ func test23ErrorHandling(t *testing.T, tempDir, secretPath, testMnemonic string,
 	require.ErrorIs(t, err, vault.ErrVersionNotFound, "get non-existent version should fail")
 
 	// Promote non-existent version
-	output, err = runSecretWithEnv(map[string]string{
+	_, err = runSecretWithEnv(map[string]string{
 		secret.EnvMnemonic: testMnemonic,
 	}, "version", "promote", "database/password", "99999999.999")
-	require.Error(t, err, "promote non-existent version should fail")
-	assert.Contains(t, output, "not found", "should indicate version not found")
+	require.ErrorIs(t, err, vault.ErrVersionNotFound, "promote non-existent version should fail")
 }
 
 func test24EnvironmentVariables(t *testing.T, tempDir, secretPath, testMnemonic, testPassphrase string) {

internal/cli/move_test.go

@@ -45,15 +45,6 @@ func TestRejectedMoveWithinVaultLeavesStateUnchanged(t *testing.T) {
 		{`mv --force work:x ""`, workX, "", true, ontoItself},
 		// "work" is a vault name, so the destination is work:x.
 		{"mv --force work:x work", workX, "work", true, ontoItself},
-		{
-			"mv work:nosuch work:y", "work:nosuch", "work:y", false,
-			"secret 'nosuch' not found",
-		},
-		// Only an existing vault is used.
-		{
-			"mv --force nosuch:x nosuch:y", "nosuch:x", "nosuch:y", true,
-			"vault 'nosuch' does not exist",
-		},
 	}
 
 	for _, tt := range tests {
@@ -70,6 +61,33 @@ func TestRejectedMoveWithinVaultLeavesStateUnchanged(t *testing.T) {
 		})
 	}
 
+	missing := []struct {
+		command      string
+		source, dest string
+		force        bool
+		want         error
+	}{
+		{
+			"mv work:nosuch work:y", "work:nosuch", "work:y", false,
+			vault.ErrSecretNotFound,
+		},
+		// Only an existing vault is used.
+		{
+			"mv --force nosuch:x nosuch:y", "nosuch:x", "nosuch:y", true,
+			vault.ErrVaultNotFound,
+		},
+	}
+
+	for _, tt := range missing {
+		t.Run(tt.command, func(t *testing.T) {
+			t.Parallel()
+
+			requireRejectedAndUnchanged(t, before, tt.want, func(c *cli.Instance) error {
+				return c.MoveSecret(&cobra.Command{}, tt.source, tt.dest, tt.force)
+			})
+		})
+	}
+
 	// Each of these spells "work" a second way. The spelling is not a valid
 	// vault name, so the move is not taken for a move between two vaults,
 	// which would delete the destination, here the source.

internal/cli/path_traversal_test.go

@@ -297,18 +297,8 @@ func TestInvalidVersionLeavesVaultsUnchanged(t *testing.T) {
 	for _, tt := range commands {
 		for _, version := range []string{"", ".", "..", "../../..", "a/b"} {
 			t.Run(fmt.Sprintf("%s %q", tt.command, version), func(t *testing.T) {
-				fs := newFsFromSnapshot(t, before)
-
-				err := tt.run(cli.NewCLIInstanceWithStateDir(fs, testStateDir), version)
-
-				require.Equal(t, before, snapshotStateDir(t, fs))
-
-				// Compared as text: `version rm` and `version promote` return
-				// internal/cli's own error of this text, which errors.Is does
-				// not match to vault.ErrVersionNotFound.
-				want := fmt.Errorf("version '%s' %w '%s'",
-					version, vault.ErrVersionNotFound, "x")
-				require.EqualError(t, err, want.Error())
+				requireRejectedAndUnchanged(t, before, vault.ErrVersionNotFound,
+					func(c *cli.Instance) error { return tt.run(c, version) })
 			})
 		}
 	}

internal/cli/secrets.go

@@ -35,10 +35,6 @@ var (
 	errSecretTooLarge     = errors.New("secret too large: exceeds 100MB limit")
 	errSecretFileTooLarge = errors.New(
 		"secret file too large: exceeds 100MB limit")
-	errSecretNotFound      = errors.New("not found")
-	errSecretExistsNoForce = errors.New(
-		"already exists (use --force to overwrite)")
-	errVaultDoesNotExist           = errors.New("does not exist")
 	errCrossVaultSourceUnqualified = errors.New(
 		"source must specify vault (e.g., vault:secret) for cross-vault move")
 	errMoveOntoItself = errors.New("cannot be moved onto itself")
@@ -776,7 +772,7 @@ func (cli *Instance) findSecretToRemove(
 
 	if !exists {
 		return secretToRemove{},
-			fmt.Errorf("secret '%s' %w", secretName, errSecretNotFound)
+			fmt.Errorf("secret '%s' %w", secretName, vault.ErrSecretNotFound)
 	}
 
 	// A secret without a versions directory has no versions, and can
@@ -907,7 +903,7 @@ func (cli *Instance) existingVault(name string) (*vault.Vault, error) {
 	}
 
 	if !slices.Contains(vaults, name) {
-		return nil, fmt.Errorf("vault '%s' %w", name, errVaultDoesNotExist)
+		return nil, fmt.Errorf("vault '%s' %w", name, vault.ErrVaultNotFound)
 	}
 
 	return vault.NewVault(cli.fs, cli.stateDir, name), nil
@@ -938,7 +934,7 @@ func (cli *Instance) moveSecretWithinVault(
 	}
 
 	if !exists {
-		return fmt.Errorf("secret '%s' %w", source, errSecretNotFound)
+		return fmt.Errorf("secret '%s' %w", source, vault.ErrSecretNotFound)
 	}
 
 	destEncoded := strings.ReplaceAll(dest, "/", "%")
@@ -963,7 +959,8 @@ func (cli *Instance) moveSecretWithinVault(
 
 	if exists {
 		if !force {
-			return fmt.Errorf("secret '%s' %w", dest, errSecretExistsNoForce)
+			return fmt.Errorf("secret '%s' %w (use --force to overwrite)",
+				dest, vault.ErrSecretExists)
 		}
 
 		err = secret.RemoveDirAtomic(cli.fs, destDir)
@@ -1028,7 +1025,7 @@ func (cli *Instance) moveSecretCrossVault(
 	exists, err := afero.DirExists(cli.fs, srcSecretDir)
 	if err != nil || !exists {
 		return fmt.Errorf("secret '%s' %w in vault '%s'",
-			srcSecretName, errSecretNotFound, srcVault.Name)
+			srcSecretName, vault.ErrSecretNotFound, srcVault.Name)
 	}
 
 	// The source is removed after the copy, so a destination that is the

internal/cli/unlockers.go

@@ -47,7 +47,6 @@ var (
 	// composes "GPG key <id> is already added as an unlocker".
 	errGPGKeyAlreadyUnlocker = errors.New(
 		"is already added as an unlocker")
-	errUnsupportedUnlockerType = errors.New("unsupported unlocker type")
 )
 
 // UnlockerInfo represents unlocker information for display
@@ -439,7 +438,7 @@ func (cli *Instance) UnlockersAdd(unlockerType string, cmd *cobra.Command) error
 		}
 
 		return fmt.Errorf("%w: %s (supported: %s)",
-			errUnsupportedUnlockerType, unlockerType, supportedTypes)
+			errInvalidUnlockerType, unlockerType, supportedTypes)
 	}
 }
 
@@ -474,7 +473,7 @@ func (cli *Instance) addPassphraseUnlocker(cmd *cobra.Command) error {
 		// Use secure passphrase input with confirmation
 		passphraseBuffer, err = readSecurePassphrase("Enter passphrase for unlocker: ")
 		if err != nil {
-			return fmt.Errorf("failed to read passphrase: %w", err)
+			return err
 		}
 		defer passphraseBuffer.Destroy()
 	}

internal/cli/unlockers_add_test.go

@@ -5,6 +5,7 @@ import (
 	"path/filepath"
 	"testing"
 
+	"git.eeqj.de/sneak/secret/internal/secret"
 	"git.eeqj.de/sneak/secret/internal/vault"
 	"github.com/awnumar/memguard"
 	"github.com/spf13/afero"
@@ -98,7 +99,7 @@ func TestAddPGPUnlockerUnknownKey(t *testing.T) {
 
 	err := instance.addPGPUnlocker(cmd)
 
-	require.ErrorContains(t, err, "failed to resolve GPG key fingerprint")
+	require.ErrorIs(t, err, secret.ErrGPGKeyNotFound)
 	assertDirEntries(t, base,
 		filepath.Join(testVaultDir(listTestVaultName), listTestUnlockersDirName),
 		listTestUnlockerDirOne)

internal/cli/vault.go

@@ -250,7 +250,7 @@ func (cli *Instance) resolvePassphrase() (*memguard.LockedBuffer, func(), error)
 	// Use secure passphrase input with confirmation
 	passphraseBuffer, err := readSecurePassphrase("Enter passphrase for unlocker: ")
 	if err != nil {
-		return nil, nil, fmt.Errorf("failed to read passphrase: %w", err)
+		return nil, nil, err
 	}
 
 	return passphraseBuffer, passphraseBuffer.Destroy, nil
@@ -353,7 +353,7 @@ func (cli *Instance) vaultImportPreflight(
 
 	if !exists {
 		return "", "", "", fmt.Errorf("vault '%s' %w",
-			vaultName, errVaultDoesNotExist)
+			vaultName, vault.ErrVaultNotFound)
 	}
 
 	// Check if vault already has a public key
@@ -644,7 +644,7 @@ func (cli *Instance) findVaultToRemove(name string) (vaultToRemove, error) {
 
 	if !slices.Contains(vaults, name) {
 		return vaultToRemove{},
-			fmt.Errorf("vault '%s' %w", name, errVaultDoesNotExist)
+			fmt.Errorf("vault '%s' %w", name, vault.ErrVaultNotFound)
 	}
 
 	if len(vaults) == 1 {

internal/cli/version.go

@@ -23,7 +23,6 @@ const (
 
 // Sentinel errors for version operations
 var (
-	errVersionNotFound            = errors.New("not found for secret")
 	errCannotRemoveCurrentVersion = errors.New("promote another version first")
 )
 
@@ -156,7 +155,7 @@ func (cli *Instance) ListVersions(cmd *cobra.Command, secretName string) error {
 	if !exists {
 		secret.Debug("Secret not found", "secret_name", secretName)
 
-		return fmt.Errorf("secret '%s' %w", secretName, errSecretNotFound)
+		return fmt.Errorf("secret '%s' %w", secretName, vault.ErrSecretNotFound)
 	}
 
 	// List all versions
@@ -289,7 +288,7 @@ func (cli *Instance) PromoteVersion(
 
 	if !exists {
 		return fmt.Errorf("version '%s' %w '%s'",
-			version, errVersionNotFound, secretName)
+			version, vault.ErrVersionNotFound, secretName)
 	}
 
 	// Update the current symlink using the proper function
@@ -374,7 +373,7 @@ func (cli *Instance) findVersionToRemove(
 
 	if !exists {
 		return versionToRemove{},
-			fmt.Errorf("secret '%s' %w", secretName, errSecretNotFound)
+			fmt.Errorf("secret '%s' %w", secretName, vault.ErrSecretNotFound)
 	}
 
 	// Check if version exists
@@ -386,7 +385,7 @@ func (cli *Instance) findVersionToRemove(
 
 	if !exists {
 		return versionToRemove{}, fmt.Errorf("version '%s' %w '%s'",
-			version, errVersionNotFound, secretName)
+			version, vault.ErrVersionNotFound, secretName)
 	}
 
 	// Get current version

internal/cli/version_test.go

@@ -171,7 +171,7 @@ func TestListVersionsNonExistentSecret(t *testing.T) {
 
 	// Try to list versions of non-existent secret
 	err := cli.ListVersions(cmd, "nonexistent/secret")
-	require.ErrorIs(t, err, errSecretNotFound)
+	require.ErrorIs(t, err, vault.ErrSecretNotFound)
 }
 
 func TestPromoteVersionCommand(t *testing.T) {
@@ -265,7 +265,7 @@ func TestPromoteNonExistentVersion(t *testing.T) {
 
 	// Try to promote non-existent version
 	err = cli.PromoteVersion(cmd, "test/secret", "20991231.999")
-	require.ErrorIs(t, err, errVersionNotFound)
+	require.ErrorIs(t, err, vault.ErrVersionNotFound)
 }
 
 func TestGetSecretWithVersion(t *testing.T) {

internal/secret/crypto.go

@@ -166,19 +166,20 @@ func DecryptWithPassphrase(
 
 // ReadPassphrase reads a passphrase securely from the terminal without echoing
 // This version is for unlocking and doesn't require confirmation
-// Returns a LockedBuffer containing the passphrase for secure memory handling
+// Returns a LockedBuffer containing the passphrase for secure memory handling.
+// Every error it returns wraps ErrPassphraseNotRead.
 func ReadPassphrase(prompt string) (*memguard.LockedBuffer, error) {
 	// Check if stdin is a terminal
 	if !term.IsTerminal(syscall.Stdin) {
 		// Not a terminal - never read passphrases from piped input
 		// for security reasons
-		return nil, errStdinNotTerminal
+		return nil, fmt.Errorf("%w: %w", ErrPassphraseNotRead, errStdinNotTerminal)
 	}
 
 	// stdin is a terminal, check if stderr is also a terminal for
 	// interactive prompting
 	if !term.IsTerminal(syscall.Stderr) {
-		return nil, errStderrNotTerminal
+		return nil, fmt.Errorf("%w: %w", ErrPassphraseNotRead, errStderrNotTerminal)
 	}
 
 	// Both stdin and stderr are terminals - use secure password reading
@@ -186,14 +187,14 @@ func ReadPassphrase(prompt string) (*memguard.LockedBuffer, error) {
 
 	passphrase, err := term.ReadPassword(syscall.Stdin)
 	if err != nil {
-		return nil, fmt.Errorf("failed to read passphrase: %w", err)
+		return nil, fmt.Errorf("%w: %w", ErrPassphraseNotRead, err)
 	}
 
 	// Print newline to stderr since ReadPassword doesn't echo
 	fmt.Fprintln(os.Stderr)
 
 	if len(passphrase) == 0 {
-		return nil, errEmptyPassphrase
+		return nil, fmt.Errorf("%w: %w", ErrPassphraseNotRead, errEmptyPassphrase)
 	}
 
 	// Create a secure buffer and copy the passphrase

internal/secret/keychainunlocker_cgo.go

@@ -15,7 +15,7 @@ import (
 // storeInKeychain stores data in the macOS keychain using keybase/go-keychain
 func storeInKeychain(itemName string, data *memguard.LockedBuffer) error {
 	if data == nil {
-		return fmt.Errorf("data buffer is nil")
+		return errNilDataBuffer
 	}
 	if err := validateKeychainItemName(itemName); err != nil {
 		return fmt.Errorf("invalid keychain item name: %w", err)

internal/secret/keychainunlocker_test.go

@@ -130,8 +130,7 @@ func TestKeychainNilData(t *testing.T) {
 
 	// Test storing nil data
 	err := storeInKeychain("test-item", nil)
-	assert.Error(t, err, "Expected error when storing nil data")
-	assert.Contains(t, err.Error(), "data buffer is nil")
+	require.ErrorIs(t, err, errNilDataBuffer)
 }
 
 func TestKeychainLargeData(t *testing.T) {

internal/secret/passphraseunlocker.go

@@ -11,9 +11,9 @@ import (
 	"github.com/spf13/afero"
 )
 
-// ErrPassphraseNotRead is wrapped in the error of a passphrase unlocker
-// that could not read its passphrase from the terminal, for example because
-// there is none. The unlocker itself was not tried.
+// ErrPassphraseNotRead is wrapped in every error of ReadPassphrase: there
+// is no terminal to read the passphrase from, reading it failed, or it was
+// empty. A passphrase unlocker that fails with it was not tried.
 var ErrPassphraseNotRead = errors.New("failed to read passphrase")
 
 // PassphraseUnlocker represents a passphrase-protected unlocker
@@ -155,7 +155,7 @@ func (p *PassphraseUnlocker) getPassphrase() (*memguard.LockedBuffer, error) {
 	if err != nil {
 		Debug("Failed to read passphrase", "error", err, "unlocker_id", p.GetID())
 
-		return nil, fmt.Errorf("%w: %w", ErrPassphraseNotRead, err)
+		return nil, err
 	}
 
 	return secureBuffer, nil

internal/secret/pgpunlocker.go

@@ -18,6 +18,10 @@ import (
 	"github.com/spf13/afero"
 )
 
+// gpgNoPublicKeyStatus is the status line gpg writes when it has no key for
+// the ID it was asked to list: 9 is gpg's error code for "No public key".
+const gpgNoPublicKeyStatus = "[GNUPG:] ERROR keylist.getkey 9\n"
+
 var (
 	errGPGKeyIDEmpty    = errors.New("GPG key ID cannot be empty")
 	errInvalidGPGKeyID  = errors.New("invalid GPG key ID format")
@@ -25,6 +29,10 @@ var (
 	errNilDataBuffer    = errors.New("data buffer is nil")
 )
 
+// ErrGPGKeyNotFound is returned by ResolveGPGKeyFingerprint for a key ID
+// that matches no key in the GPG keyring.
+var ErrGPGKeyNotFound = errors.New("GPG key not found")
+
 // Variables to allow overriding in tests
 var (
 	// GPGEncryptFunc is the function used for GPG encryption
@@ -367,14 +375,20 @@ func ResolveGPGKeyFingerprint(keyID string) (string, error) {
 		return "", fmt.Errorf("invalid GPG key ID: %w", err)
 	}
 
-	// Use GPG to get the full fingerprint for the key
+	// Use GPG to get the full fingerprint for the key. --status-fd 1 adds
+	// gpg's status lines to the output.
 	cmd := exec.CommandContext( //nolint:gosec // G204: keyID validated above
 		context.Background(),
-		"gpg", "--list-keys", "--with-colons", "--fingerprint", keyID,
+		"gpg", "--status-fd", "1",
+		"--list-keys", "--with-colons", "--fingerprint", keyID,
 	)
 
 	output, err := cmd.Output()
 	if err != nil {
+		if strings.Contains(string(output), gpgNoPublicKeyStatus) {
+			return "", fmt.Errorf("%w: %s", ErrGPGKeyNotFound, keyID)
+		}
+
 		return "", fmt.Errorf("failed to resolve GPG key fingerprint: %w", err)
 	}
 

pkg/bip85/bip85.go

@@ -59,16 +59,6 @@ var (
 	// ErrInvalidBase85PwdLen is returned when the Base85 password length
 	// is out of range.
 	ErrInvalidBase85PwdLen = errors.New("pwdLen must be between 10 and 80")
-	// ErrPasswordTooShort is returned when the derived material is
-	// shorter than the requested password length. It carries only the
-	// middle of the message, which the caller composes as
-	// "derived password length <n> is shorter than requested length <m>",
-	// so the emitted text is unchanged.
-	ErrPasswordTooShort = errors.New("is shorter than requested length")
-	// ErrEncodedTooShort is returned when the encoded material is shorter
-	// than the requested password length. Composed as
-	// "encoded length <n> is less than requested length <m>".
-	ErrEncodedTooShort = errors.New("is less than requested length")
 )
 
 // Version bytes for extended keys
@@ -381,14 +371,8 @@ func DeriveBase64Password(
 	// Remove any padding
 	encodedStr = strings.TrimRight(encodedStr, "=")
 
-	// Slice to the desired password length
-	if len(encodedStr) < int(pwdLen) {
-		return "", fmt.Errorf(
-			"derived password length %d %w %d",
-			len(encodedStr), ErrPasswordTooShort, pwdLen,
-		)
-	}
-
+	// Slice to the desired password length: 64 bytes of entropy leave 86
+	// characters, the most pwdLen allows
 	return encodedStr[:pwdLen], nil
 }
 
@@ -411,14 +395,8 @@ func DeriveBase85Password(
 	// Base85 encode all 64 bytes of entropy using the RFC1924 character set
 	encoded := encodeBase85WithRFC1924Charset(entropy)
 
-	// Slice to the desired password length
-	if len(encoded) < int(pwdLen) {
-		return "", fmt.Errorf(
-			"encoded length %d %w %d",
-			len(encoded), ErrEncodedTooShort, pwdLen,
-		)
-	}
-
+	// Slice to the desired password length: 64 bytes of entropy give 80
+	// characters, the most pwdLen allows
 	return encoded[:pwdLen], nil
 }