Debugging rust-analyzer rebuilds

[Dietr1ch]

Hi!

I'm using rust-analyzer and I'm seeing that differences in configuration trigger rebuilds of a lot of crates I'm not touching. I'd like to find a nice way of finding out what's broken.

I think the culprit of my current issue is the use of --all-targets --all-features on my Justfile, and emacs not configuring rust-analyzer with those, but what I'm really after isn't changes to .rust-analyzer.toml+Justfile to gets things in sync, but a way to debug when the build artifacts need to get thrown away and why.

It'd be nice if a warning would be raised if somewhat fresh artifacts are being thrown away because of configuration differences.

Maybe the sets of build configurations is also persisted and flapping between multiple sets of configuration options can be detected (and maybe be attributed to a program too).

[ChayimFriedman2]

rust-analyzer does not know when Cargo decides to rebuild, therefore it can't warn you about that. However if you set RA_LOG=info (for example in rust-analyzer.server.extraEnv), it should print the command it uses I believe.

[lnicola]

You can also add -v to the cargo arguments.

[Dietr1ch]

So should then cargo be the one detecting configuration flapping?

[lnicola]

It was always cargo doing that. This usually happens because of environment variables defined in the shell config file (so starting your IDE from the DE gets you a different environment compared to the terminal).