Error after successful return (bug not located): "Unwrap error", after printing -1's result

[mcint]

Describe the bug you encountered:
Query returns or reports and error after normal, successful usage.

Describe what you expected to happen:
Print result of fd -d 3 -1 cheat.sheets . and exit.

Does not error on fd -d 3 -1 cheat.sheets, without final . search path arg.

What version of fd are you using?
fd 8.1.1
Which operating system / distribution are you on?
Darwin 18.7.0 x86_64

^C^C
$ env RUST_BACKTRACE=1 fd -d 3 -1 cheat.sheets .
hosting/Reference/cheat.sheets
thread '<unnamed>' panicked at 'called `Result::unwrap()` on an `Err` value: "SendError(..)"', src/walk.rs:371:21
stack backtrace:
thread '<unnamed>' panicked at 'called `Result::unwrap()` on an `Err` value: "SendError(..)"', src/walk.rs:371:21
thread '<unnamed>' panicked at 'called `Result::unwrap()` on an `Err` value: "SendError(..)"', src/walk.rs:371:21
   0: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
   1: core::fmt::write
   2: std::io::Write::write_fmt
   3: std::panicking::default_hook::{{closure}}
   4: std::panicking::rust_panic_with_hook
   5: rust_begin_unwind
   6: core::panicking::panic_fmt
   7: core::result::unwrap_failed
   8: fd::walk::spawn_senders::{{closure}}::{{closure}}
   9: <ignore::walk::FnVisitorImp as ignore::walk::ParallelVisitor>::visit
  10: ignore::walk::Worker::run_one
  11: crossbeam_utils::thread::ScopedThreadBuilder::spawn::{{closure}}
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
stack backtrace:
   0: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
   1: core::fmt::write
   2: std::io::Write::write_fmt
   3: std::panicking::default_hook::{{closure}}
   4: std::panicking::rust_panic_with_hook
   5: rust_begin_unwind
   6: core::panicking::panic_fmt
   7: core::result::unwrap_failed
   8: fd::walk::spawn_senders::{{closure}}::{{closure}}
   9: <ignore::walk::FnVisitorImp as ignore::walk::ParallelVisitor>::visit
  10: ignore::walk::Worker::run_one
  11: crossbeam_utils::thread::ScopedThreadBuilder::spawn::{{closure}}
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Any', /Users/brew/Library/Caches/Homebrew/cargo_cache/registry/src/github.com-1ecc6
299db9ec823/ignore-0.4.15/src/walk.rsstack backtrace:
:1294:17
   0: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
   1: core::fmt::write
   2: std::io::Write::write_fmt
   3: std::panicking::default_hook::{{closure}}
   4: std::panicking::rust_panic_with_hook
   5: rust_begin_unwind
   6: core::panicking::panic_fmt
   7: core::result::unwrap_failed
   8: fd::walk::spawn_senders::{{closure}}::{{closure}}
   9: <ignore::walk::FnVisitorImp as ignore::walk::ParallelVisitor>::visit
  10: ignore::walk::Worker::run_one
  11: crossbeam_utils::thread::ScopedThreadBuilder::spawn::{{closure}}
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
stack backtrace:
   0: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
   1: core::fmt::write
   2: std::io::Write::write_fmt
   3: std::panicking::default_hook::{{closure}}
   4: std::panicking::rust_panic_with_hook
   5: rust_begin_unwind
   6: core::panicking::panic_fmt
   7: core::result::unwrap_failed
   8: ignore::walk::WalkParallel::visit
   9: fd::walk::scan
  10: fd::run
  11: fd::main
  12: std::rt::lang_start::{{closure}}
  13: main
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[mcint]

Uhh. Regarding /Users/brew/Library/Caches/Homebrew/cargo_cache/registry/src/github.com-1ecc6299db9ec823/ignore-0.4.15/src/walk.rs...stack backtrace:...``:1294:17`

I don't even have ignore-0.4.15 in the cargo sources. I think this is probably a packaging bug, brew.

λ ~ fd walk.rs .cargo
.cargo/registry/src/github.com-1ecc6299db9ec823/ignore-0.4.10/examples/walk.rs
.cargo/registry/src/github.com-1ecc6299db9ec823/ignore-0.4.10/src/walk.rs
.cargo/registry/src/github.com-1ecc6299db9ec823/git2-0.13.8/src/revwalk.rs
.cargo/registry/src/github.com-1ecc6299db9ec823/ignore-0.4.14/src/walk.rs
.cargo/registry/src/github.com-1ecc6299db9ec823/ignore-0.4.14/examples/walk.rs

[sharkdp]

Thank you for reporting this. I actually managed to reproduce it (it also hangs for me sometimes) and I think it can be fixed easily. The problem appears in directories with permission problems (that would show up when using --show-errors). For me, I can do this in /etc to provoke the bug:

fd -1 -d3 foo

We shouldn't have used .unwrap() on send(…) calls.

[sharkdp]

Should be fixed via #679.

[sharkdp]

fix released in v8.2.0.