We previously used serde's stream deserializer to read json blobs from
the cargo output. It has an issue though: If the deserializer encounters
invalid input, it gets stuck reporting the same error again and again
because it is unable to foward over the input until it reaches a new
valid object.
Reading a line at a time and manually deserializing fixes this issue,
because cargo makes sure to only outpu one json blob per line, so should
we encounter invalid input, we can just skip a line and continue.
The main reason this would happen is stray printf-debugging in
procedural macros, so we still report that an error occured, but we
handle it gracefully now.
Fixes#2935
2924: Modify ordering of drops in check watcher to only ever have one cargo r=matklad a=kiljacken
Due to the way drops are ordered when assigning to a mutable variable we
were launching a new cargo sub-process before letting the old one quite.
By explicitly replacing the original watcher with a dummy first, we
ensure it is dropped and the process is completed, before we start the
new process.
Co-authored-by: Emil Lauridsen <mine809@gmail.com>
Due to the way drops are ordered when assigning to a mutable variable we
were launching a new cargo sub-process before letting the old one quite.
By explicitly replacing the original watcher with a dummy first, we
ensure it is dropped and the process is completed, before we start the
new process.
@matklad mentioned this might be a good idea.
So the general idea is that we don't really need the lock, as we can
just clone the check watcher state when creating a snapshot. We can then
use `Arc::get_mut` to get mutable access to the state from `WorldState`
when needed.
Running with this it seems to improve responsiveness a bit while cargo
is running, but I have no hard numbers to prove it. In any case, a
serialization point less is always better when we're trying to be
responsive.
2681: cargo-watcher: Resolve macro call site in more cases r=matklad a=kiljacken
This resolves the actual macro call site in a few more cases, f.x. when a macro invokes `compile_error!` (I'm looking at you `ra_hir_def::path::__path`).
Co-authored-by: Emil Lauridsen <mine809@gmail.com>
