Implement From<(T: Device, Error)> for Error

Not all users of the authenticate methods want to use the device after
an error, so implementing From<(T: Device, Error)> for Error makes it
easier for them to discard the device.

3 files changed, 9 insertions, 1 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 70bd7cb..c28c228 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,6 +24,7 @@
 - Add `Error::Utf8Error` variant.
   - Return `Result<Version>` instead of `Version` from `get_library_version`.
   - Return `Error::Utf8Error` if libnitrokey returns an invalid UTF-8 string.
+- Implement `From<(T: Device, Error)>` for `Error`.
 
 # v0.3.4 (2019-01-20)
 - Fix authentication methods that assumed that `char` is signed.
diff --git a/TODO.md b/TODO.md
index 0467f1d..49e4e08 100644
--- a/TODO.md
+++ b/TODO.md
@@ -8,7 +8,6 @@
 - Fix timing issues with the `totp_no_pin` and `totp_pin` test cases.
 - Clear passwords from memory.
 - Find a nicer syntax for the `write_config` test.
-- Consider implementing `Into<CommandError>` for `(Device, CommandError)`
 - Lock password safe in `PasswordSafe::drop()` (see [nitrokey-storage-firmware
   issue 65][]).
 - Disable creation of multiple password safes at the same time.
diff --git a/src/error.rs b/src/error.rs
index 4b82c6e..551dd0f 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -4,6 +4,8 @@ use std::os::raw;
 use std::result;
 use std::str;
 
+use crate::device;
+
 /// An error returned by the nitrokey crate.
 #[derive(Debug)]
 pub enum Error {
@@ -67,6 +69,12 @@ impl From<str::Utf8Error> for Error {
     }
 }
 
+impl<T: device::Device> From<(T, Error)> for Error {
+    fn from((_, err): (T, Error)) -> Self {
+        err
+    }
+}
+
 impl error::Error for Error {
     fn source(&self) -> Option<&(dyn error::Error + 'static)> {
         match *self {