clippy fails with "Compiler not supported: Unrecognized option: E"

[teor2345]

When I run cargo clippy in a new Rust project with Rust nightly-2020-02-19 and later, I get the following error:
Compiler not supported: "error: Unrecognized option: \'E\'\n\n"

cargo build and cargo test run without any errors. nightly-2020-02-18 and earlier run without any errors.

Here are the relevant versions:

$ sccache --version
sccache 0.2.13
$ cargo-clippy --version
clippy 0.1.52 (e37a13c 2021-02-28)
$ uname -a
Linux ... 5.4.96 #1-NixOS SMP Sun Feb 7 14:35:50 UTC 2021 x86_64 GNU/Linux

Here are the full logs:

$ cargo clippy --verbose
    Checking clippy-test v0.1.0 (/home/dev/clippy-test)
     Running `sccache /home/dev/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/clippy-driver rustc --crate-name clippy_test --edition=2018 src/main.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type bin --emit=dep-info,metadata -C embed-bitcode=no -C debuginfo=2 -C metadata=9ceb40d693978c75 -C extra-filename=-9ceb40d693978c75 --out-dir /home/dev/clippy-test/target/debug/deps -C incremental=/home/dev/clippy-test/target/debug/incremental -L dependency=/home/dev/clippy-test/target/debug/deps`
error: failed to execute compile
caused by: Compiler not supported: "error: Unrecognized option: \'E\'\n\n"
error: could not compile `clippy-test`

Caused by:
  process didn't exit successfully: `sccache /home/dev/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/clippy-driver rustc --crate-name clippy_test --edition=2018 src/main.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type bin --emit=dep-info,metadata -C embed-bitcode=no -C debuginfo=2 -C metadata=9ceb40d693978c75 -C extra-filename=-9ceb40d693978c75 --out-dir /home/dev/clippy-test/target/debug/deps -C incremental=/home/dev/clippy-test/target/debug/incremental -L dependency=/home/dev/clippy-test/target/debug/deps` (exit code: 2)
Exit 101

[luser]

See #423

[teor2345]

See #423

Thanks, I understand that sccache has limited support for clippy-driver.

But to be clear, this defect is about a sccache "unsupported compiler" error that only happens on recent rustc nightlies, and only with clippy.

On rustup nightly-2020-02-18, the following command works:

RUSTC_WRAPPER="sccache" cargo clippy

But on nightly-2020-02-18, it errors.

On all these versions, the following command works:

RUSTC_WRAPPER="" cargo clippy

So this seems like a specific sccache bug, perhaps triggered by changes in rustc nightly.

[flip1995]

This is because Clippy is now using RUSTC_WORKSPACE_WRAPPER instead of RUSTC_WRAPPER: rust-lang/cargo#8143

I don't know the details or what causes this. @ehuss do you have more insights here?

[ehuss]

Probably the same thing as #889 and rust-lang/rust-clippy#5507. Sorry, I don't really know what is behind that (or how #728 fixed it).

sccache 0.2.13

This version is over a year old, maybe try a more recent version?

[ThibsG]

I bumped to sccache 0.2.15 and I have the same issue.

[teor2345]

I upgraded to sccache 0.2.15.

Using RUSTC_WRAPPER and RUSTC_WORKSPACE_WRAPPER fails:

RUSTC_WRAPPER="sccache" RUSTC_WORKSPACE_WRAPPER="sccache" cargo

Using RUSTC_WORKSPACE_WRAPPER only succeeds:

RUSTC_WRAPPER="" RUSTC_WORKSPACE_WRAPPER="sccache" cargo

It would be nice if this got fixed, or sccache added a hint in the error message to switch to RUSTC_WORKSPACE_WRAPPER and leave RUSTC_WRAPPER empty.