Cargo clean removes target directory, even when it is a softlink

[SeseMueller]

Problem

Running cargo clean deletes the target directory, which is usually fine, because it is regenerated on the next cargo build.
However, I used a symlink for my target directory because I want my code to be synced across devices, but not bloat it with the build artifacts.

cargo clean simply removed the symlink.
In my opinion, it should either give a warning or follow the symlink; not fail silently.

Steps

1. Create a new empty project
2. Create a sylink for the target directory to somewhere else
3. Run cargo build
4. Run cargo clean

The symlink is gone and on the next cargo build, it will be a regular directory instead.

Possible Solution(s)

Always following symlinks might not be a good idea, so it should probably warn the user and abort. (To work proberly, that would require a new flag for cargo clean though)

Notes

No response

Version

cargo 1.79.0-nightly (d438c80c4 2024-03-19)
release: 1.79.0-nightly
commit-hash: d438c80c45c24be676ef5867edc79d0a14910efe
commit-date: 2024-03-19
host: aarch64-apple-darwin
libgit2: 1.7.2 (sys:0.18.2 vendored)
libcurl: 8.4.0 (sys:0.4.72+curl-8.6.0 system ssl:(SecureTransport) LibreSSL/3.3.6)
ssl: OpenSSL 1.1.1w  11 Sep 2023
os: Mac OS 14.4.1 [64-bit]

[weihanglo]

See #7510 (comment) and dicussions in the closed PR, which consider this as an expected behavior. See also alternaive designs like rust-lang/rfcs#3371 for templating target directories.

Besides alternatives, is there any specific reason you can't set CARGO_TARGET_DIR to the actual directory instead of using a symlink?

[SeseMueller]

See #7510 (comment) and dicussions in the closed PR, which consider this as an expected behavior. See also alternaive designs like rust-lang/rfcs#3371 for templating target directories.

Ok, yeah. That makes sense. But given that cargo clean is mostly a manual command, maybe it should warn the user, but proceed as normal?

Besides alternatives, is there any specific reason you can't set CARGO_TARGET_DIR to the actual directory instead of using a symlink?

I didn't realize that setting the target-dir would propagate through modules in my context, that did in fact work. Thanks for pointing that out.

[weihanglo]

From the manual:

With no options, cargo clean will delete the entire target directory.

Basically cargo clean is an rm -rf taking effect like immediately, so when seeing a warning it's too late. There is a --dry-run flag. When with doubt, users can dry-run a clean before the actual clean, such as cargo clean --verbose --dry-run. Interactive console is also an option, but due to compatibility reasons, that won't become the default behavior of cargo clean in my opinion.

Going to close this in favor of rust-lang/rfcs#3371 and CARGO_TARGET_DIR. Thank you for the report :)