Could we ever fix naming of `io::Write::write`?

[kornel]

I don't know how such information could be collected and presented for you to find it convincing.

I've lamented about this footgun before:

Poor naming of read()/write() I/O methods

I/O traits Read and Write have read() and write() methods. The problem is that it's not clear from these methods' names that they have specific behavior which doesn't guarantee reading/writing the full slice. Using these methods as if they were read_exact/write_all is a huge footgun. It's a nasty kind of bug, because depending on the underlying I/O implementation, wrong code may mostly work most of the time. I've made that mistake, I've seen others make that mistake. These methods names look in…

I've found this bug in a lot of places. In noobs' code. In code by experienced devs who work professionally on network services. In cargo. In cranelift. In rustdoc. I the png and gif crates. In xml-rs. In firecracker. In rav1e. In openssl and boring. In serde. In sccache. In flate2. In hyper. Even an early version of docs for std::io had this bug in the examples.

It's everywhere. In old code. In new code.

I just grepped for uses of .write in Rust, and already found more suspicious examples than intentional uses of write:

• rust/library/std/src/process/tests.rs at 99768c80a1c094a5cfc3b25a04e7a99de7210eae · rust-lang/rust · GitHub

• rust/library/std/src/sys/pal/unix/process/process_common/tests.rs at 22a220a1a8280a262a277fc24661511f6c4dab51 · rust-lang/rust · GitHub

• rust/src/tools/generate-windows-sys/src/main.rs at 99768c80a1c094a5cfc3b25a04e7a99de7210eae · rust-lang/rust · GitHub

And the intentional one looks like it could have been write_all too.

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Run that on any large project, and you'll find how often this had to be fixed:

git log -pS .write_all\( | grep -EA1 '^-.*\.write\(' | egrep -EB1 '^\+'

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I suspect that if Rust won't complain about implementing fn write(…) for the io::Write trait or uses of .write() inside this method, then there won't be any churn. Intentional uses of partial .write() seem to be incredibly rare.