Panic in concurrent.rs with async deadlock

[alexcrichton]

This input:

(component

  (component $child
    (core module $libc (memory (export "memory") 1))
    (core instance $libc (instantiate $libc))

    (type $future (future))
    (core func $read (canon future.read $future (memory $libc "memory")))

    (core module $m
      (import "" "read" (func $read (param i32 i32) (result i32)))

      (func (export "run") (param $future i32)
        (call $read (local.get $future) (i32.const 0))
        drop
      )
    )
    (core instance $i (instantiate $m
      (with "" (instance
        (export "read" (func $read))
      ))
    ))
    (func (export "run") (param "x" $future)
      (canon lift (core func $i "run")))
  )
  (instance $child (instantiate $child))

  (type $future (future))
  (core func $new (canon future.new $future))
  (core func $child-run (canon lower (func $child "run")))


  (core module $m
    (import "" "new" (func $new (result i32)))
    (import "" "child-run" (func $child-run (param i32)))

    (func (export "run")
      (call $child-run (call $new))
    )
  )
  (core instance $i (instantiate $m
    (with "" (instance
      (export "new" (func $new))
      (export "child-run" (func $child-run))
    ))
  ))

  (func (export "run")
    (canon lift (core func $i "run")))
)

(assert_trap (invoke "run") "something i don't know what")

currently fails with:

$ ../wasip3-prototyping/target/release/wasmtime wast -W component-model-async ./test.wast

thread 'main' panicked at /home/alex/code/wasip3-prototyping/crates/wasmtime/src/runtime/component/concurrent/futures_and_streams.rs:2238:59:
called `Option::unwrap()` on a `None` value
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[alexcrichton]

Different, but probably related, panic:

(component

  (component $child
    (core module $libc (memory (export "memory") 1))
    (core instance $libc (instantiate $libc))

    (type $future (future))
    (core func $read (canon future.read $future (memory $libc "memory")))

    (core module $m
      (import "" "read" (func $read (param i32 i32) (result i32)))

      (func (export "run") (param $future i32) (result i32)
        (call $read (local.get $future) (i32.const 0))
        drop
        i32.const 0 ;; TODO
      )

      (func (export "cb") (param i32 i32 i32 i32) (result i32)
        i32.const 0) ;; TODO
    )
    (core instance $i (instantiate $m
      (with "" (instance
        (export "read" (func $read))
      ))
    ))
    (func (export "run") (param "x" $future)
      (canon lift (core func $i "run") async (callback (func $i "cb"))))
  )
  (instance $child (instantiate $child))

  (type $future (future))
  (core func $new (canon future.new $future))
  (core func $child-run (canon lower (func $child "run")))


  (core module $m
    (import "" "new" (func $new (result i32)))
    (import "" "child-run" (func $child-run (param i32)))

    (func (export "run")
      (call $child-run (call $new))
    )
  )
  (core instance $i (instantiate $m
    (with "" (instance
      (export "new" (func $new))
      (export "child-run" (func $child-run))
    ))
  ))

  (func (export "run")
    (canon lift (core func $i "run")))
)

(assert_trap (invoke "run") "something i don't know what")

yields:

thread 'main' panicked at /home/alex/code/wasip3-prototyping/crates/wasmtime/src/runtime/component/concurrent.rs:3361:28:
called `Option::unwrap()` on a `None` value
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[dicej]

Neither of those modules panic on the current main branch. The first one completes without trapping (i.e. the test fails because it doesn't trap as expected), while the other one traps with a wasm trap: async-lifted export failed to produce a result error.

[dicej]

(Note that I had to edit the second .wast file to update the callback signature, which has changed recently in the spec)