tokio_util::run and tokio::run_on_current_thread should accept Future<Output=()> instead of Future<Output=Result<(), ()>>. Currently, all the passed futures have to add Ok(()) or futures::future::ok(()) unnecessarily to call this method.
This PR removes tokio_util::block_on - refactored compiler and file
fetcher slightly so that we can safely block there - that's because
only blocking path consist of only synchronous operations.
Additionally I removed excessive use of tokio_util::panic_on_error
and tokio_util::run_in_task and moved both functions to cli/worker.rs,
to tests module.
Closes #2960
op_fetch_module_meta_data is an op that is used by the TypeScript
compiler. TypeScript requires this op to be sync. However the
implementation of the op does things on the event loop (like fetching
HTTP resources).
In certain situations this can lead to deadlocks. The runtime's thread
pool can be filled with ops waiting on the result of
op_fetch_module_meta_data. The runtime has a maximum number of
threads it can use (the number of logical CPUs on the system).
This patch changes tokio_util::block_on to launch a new Tokio runtime
for evaluating the future, thus bipassing the max-thread problem.
This is only an issue in op_fetch_module_meta_data. Other synchronous
ops are truly synchornous, not interacting with the event loop. TODO
comments are added to direct future development.
