`cargo fix` does not warn about modifying untracked files

[TonalidadeHidrica]

Transferred from rust-lang/rust-clippy#9838.

Summary

When cargo clippy --fix is ran on a crate that is not managed by a VCS, it warns about it and does not modify the code. This also happens if cargo clippy --fix is ran in a git repository that has uncommiteed changes. However, when it is ran on a repository with uncommited changes but without any commit, it modifies the code without an error or a warning.

Reproducer

set -eux

cargo +nightly new repro
cd repro
echo "fn main() { let _ = 0.clone(); }" > src/main.rs
cargo +nightly clippy --fix
cat src/main.rs

+ cargo +nightly new repro
     Created binary (application) `repro` package
+ cd repro
+ echo 'fn main() { let _ = 0.clone(); }'
+ cargo +nightly clippy --fix
    Checking repro v0.1.0 (/home/username/repro)
       Fixed src/main.rs (1 fix)
    Finished dev [unoptimized + debuginfo] target(s) in 0.19s
+ cat src/main.rs
fn main() { let _ = 0; }

Version

rustc 1.67.0-nightly (42325c525 2022-11-11)
binary: rustc
commit-hash: 42325c525b9d3885847a3f803abe53c562d289da
commit-date: 2022-11-11
host: x86_64-unknown-linux-gnu
release: 1.67.0-nightly
LLVM version: 15.0.4

Additional Labels

No response

[ehuss]

Transferred to rust-lang/cargo, as the rustfix repo is only for the library which is not responsible for the determination of what to modify.

[0xPoe]

@rustbot claim

I'll try to fix it.

[0xPoe]

@ehuss Do you mind giving some tips about which code causes this issue? I read cargo fix code, but it seems for cargo fix instead of cargo clippy --fix?

[0xPoe]

I think the real root cause is these files are untracked files. So

cargo/src/cargo/ops/fix.rs

Line 157 in ba607b2

for status in repo.statuses(Some(&mut repo_opts))?.iter() {

this code can not find these files.

For example, you can try this to test this behavior:

set -eux

cargo +nightly new repro
cd repro
echo "fn main() { let _ = 0.clone(); }" > src/main.rs
git add .
git commit -m "test"
echo "fn main() { let _ = 0.clone(); }" > src/main1.rs
cargo +nightly clippy --fix
cat src/main.rs

You will find cargo clippy fix will ignore src/main1.rs because this file is untracked.

So I think this is probably not a bug.

[ehuss]

I think the StatusOpts needs to set include_untracked(true).

[0xPoe]

I think the StatusOpts needs to set include_untracked(true).

It works! Thanks!