Cargo clippy crashes in root of workspace

[sanmai-NL]

env RUST_BACKTRACE=1 cargo +nightly clippy

thread 'main' panicked at 'could not find parent of path /', /home/sanmai/.cargo/bin/registry/src/git.luolix.top-1ecc6299db9ec823/clippy-0.0.165/src/main.rs:250:51
stack backtrace:
   0: std::sys::imp::backtrace::tracing::imp::unwind_backtrace
             at /checkout/src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1: std::sys_common::backtrace::_print
             at /checkout/src/libstd/sys_common/backtrace.rs:71
   2: std::panicking::default_hook::{{closure}}
             at /checkout/src/libstd/sys_common/backtrace.rs:60
             at /checkout/src/libstd/panicking.rs:381
   3: std::panicking::default_hook
             at /checkout/src/libstd/panicking.rs:397
   4: std::panicking::rust_panic_with_hook
             at /checkout/src/libstd/panicking.rs:577
   5: std::panicking::begin_panic
             at /checkout/src/libstd/panicking.rs:538
   6: std::panicking::begin_panic_fmt
             at /checkout/src/libstd/panicking.rs:522
   7: cargo_clippy::main
   8: __rust_maybe_catch_panic
             at /checkout/src/libpanic_unwind/lib.rs:99
   9: std::rt::lang_start
             at /checkout/src/libstd/panicking.rs:459
             at /checkout/src/libstd/panic.rs:361
             at /checkout/src/libstd/rt.rs:59
  10: __libc_start_main
  11: _start

Meta

cargo +nightly clippy -V

0.0.165

See also #1515

[oli-obk]

I cannot reproduce. On which crate are you running it and from which directory?

[sanmai-NL]

The output of pwd is /home/sanmai/devel/gitlab.com/Structure-Systems/SE/Rust. I am running it from a workspace, and it contains unpublished crates. To clarify, the command in this case was not expected to succeed.

env RUST_BACKTRACE=1 cargo +nightly clippy --all

does not fail in the same way.

[oli-obk]

So I'm assuming the Cargo.toml is in that folder?

How are the other crates positioned relative to it? We have a workspace test for

• workspace_root
  • subcrate

And that works from both directories + any subdirectory of either.

[radix]

I'm getting this too, in github.com/radix/pandt. I'm using windows 10 and running it from the root of the repository.

C:\Users\radix\Projects\pandt [master ↑]> cargo clippy
thread 'main' panicked at 'could not find parent of path \\?\C:\', C:\Users\radix\.cargo\registry\src\git.luolix.top-1ecc6299db9ec823\clippy-0.0.165\src/main.rs:250:51

[oli-obk]

I wrote a fun comment:

                        // We'll never reach the filesystem root, because to get to this point in the
                        // code
                        // the call to `cargo_metadata::metadata` must have succeeded. So it's okay to
                        // unwrap the current path's parent.

So... I was wrong. I don't know why yet, though.

[sanmai-NL]

@oli-obk: I have .cargo directories at multiple layers, one in the workspace root dir and one in each workspace member dir (and one globally in my home dir). Does this help track down the problem?

[chordowl]

Just ran into this crash myself. My (complete!) workspace Cargo.toml looked something like this:

[workspace]

members = [
    "foo",
    "bar",
    "baz",
]

Since @oli-obk said that there was a workspace test, I looked at that and found that the test workspace had a [package] section while mine did not. After prepending that to my workspace Cargo.toml, it doesn't crash anymore, instead saying error: Could not obtain cargo metadata. (presumably because I still have neither [lib] nor [[bin]] sections in my workspace Cargo.toml?? This is pure speculation).

While this makes the crash go away, it doesn't really make sense for me to add a [package] section to my workspace's Cargo.toml since it really isn't a package -- it would be nice if I could run cargo +nightly clippy in my workspace root to just check all its members with clippy. Even without the package prefix, cargo +nightly clippy --all works, so I'm a happy camper either way.

[samueltardieu]

You can also reproduce it with:

% git clone https://github.com/hashmismatch/packed_struct.rs
% cd packed_struct.rs
% cargo clippy
thread 'main' panicked at 'could not find parent of path /', src/main.rs:124:48
note: Run with `RUST_BACKTRACE=1` for a backtrace.

[phansch]

Looks like this is fixed with 0.0.191 (possibly in #2585). I'm going ahead and close this because the offending code has been removed and is now handled by cargo check.

@sanmai-NL Feel free to re-open if you still get this crash with 0.0.191.