yaahc
Doesn't work correctly with new Rust inline formatting
Nowadays Rust supports inline formatting for variables like format!("Expected {a} to be {b}").
This syntax works correctly in format!, format_args!, anyhow! and a lot of other contexts.
However, in eyre, somewhat surprisingly, it treats the string as a literal and prints without interpolation, even though eyre itself has support for formatting when arguments are passed explicitly. It seems this stems from all macros (ensure!, bail!, eyre!) having a separate branch that catches string literal with no following arguments in a special way:
macro_rules! eyre {
($msg:literal $(,)?) => { ... };
($err:expr $(,)?) => { ... };
($fmt:expr, $($arg:tt)*) => { ... };
}
Ah, turns out its already been fixed, but has not been released yet. Thx for all the hard work updating it. Can't wait for the new release!
TBH, the implementation seems a bit convoluted, but I might simply not know enough about it. Most implementations I have seen simply rely on format_args! like so:
macro_rules! foo {
($($arg:tt)+) => {
format_args!($($arg)+)
};
}
I don't understand how the referenced lines are related to feature in question.
They are used https://github.com/eyre-rs/eyre/blob/0b24ae558f4779afccb1dfc4640c57d9922ff70e/eyre/src/lib.rs#L1231-L1234 and in a test https://github.com/eyre-rs/eyre/blob/0b24ae558f4779afccb1dfc4640c57d9922ff70e/eyre/tests/test_macros.rs#L78-L85