Merge #1446

1446: Overhaul Nix's error types r=asomers a=asomers

For many of Nix's consumers it be convenient to easily convert a Nix
error into a std::io::Error.  That's currently not possible because of
the InvalidPath, InvalidUtf8, and UnsupportedOperation types that have
no equivalent in std::io::Error.

However, very few of Nix's public APIs actually return those unusual
errors.  So a more useful API would be for Nix's standard error type to
implement Into<std::io::Error>, and the few functions that must return
unusual errors like InvalidUtf8 should use bespoke error types.

This commit prototypes that approach by modifying just one function, for
now, to use the new error type.

Co-authored-by: Alan Somers <asomers@gmail.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fcc8d4c2..4fe700d8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,16 @@ This project adheres to [Semantic Versioning](https://semver.org/).
   (#[1457](https://github.com/nix-rust/nix/pull/1457))
 
 ### Changed
+- `ptsname_r` now returns a lossily-converted string in the event of bad UTF,
+  just like `ptsname`.
+  ([#1446](https://github.com/nix-rust/nix/pull/1446))
+- Nix's error type is now a simple wrapper around the platform's Errno.  This
+  means it is now `Into<std::io::Error>`.  It's also `Clone`, `Copy`, `Eq`, and
+  has a small fixed size.  It also requires less typing.  For example, the old
+  enum variant `nix::Error::Sys(nix::errno::Errno::EINVAL)` is now simply
+  `nix::Error::EINVAL`.
+  ([#1446](https://github.com/nix-rust/nix/pull/1446))
+
 ### Fixed
 ### Removed