Test explorer forces rebuild of procedural macros

[zaneduffield]

rust-analyzer version: (eg. output of "rust-analyzer: Show RA Version" command, accessible in VSCode via Ctrl/⌘+Shift+P)

0.3.1924-standalone (5dbe3fe 2024-04-14)

rustc version: (eg. output of rustc -V)

rustc 1.77.1 (7cf61ebde 2024-03-27)

editor or extension: (eg. VSCode, Vim, Emacs, etc. For VSCode users, specify your extension version; for users of other editors, provide the distribution if applicable)

VSCode, v0.3.1924

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When a crate uses procedural macros, the new Test Explorer seems to disagree with cargo in my terminal about what needs to be recompiled. It's as if they are using different build settings (e.g. RUSTFLAGS).

Specifically, if I alternate cargo test and the 'Run Tests' button in the Test Explorer UI, then they takes turns rebuilding the procedural macros

   Compiling proc-macro2 v1.0.81
   Compiling quote v1.0.36
   Compiling syn v2.0.60
   Compiling yare-macro v3.0.0
   Compiling yare v3.0.0
   Compiling ra-proc-macro-rebuild-issue v0.1.0

I don't have any value for the RUSTFLAGS environment variable (or any other setting that I know of that might influence build cache invalidation). Furthermore, this issue doesn't seem to occur when the project doesn't use procedural macros.

Also, I can reproduce this issue with the first version of RA that had the Test Explorer.

Reproducible example: https://github.com/zaneduffield/ra-proc-macro-rebuild-issue

[zaneduffield]

Similar to #17149.
I'll see if the workaround described in #17149 (comment) works for me tomorrow.

[zaneduffield]

Similar to #17149. I'll see if the workaround described in #17149 (comment) works for me tomorrow.

I can confirm that this workaround does work for me.