Errors because runtime::Runtime::block_on() does not set reactor, executor, or timer defaults for the context

[fordN]

Version

tokio-io v0.1.7
tokio-codec v0.1.0
tokio-current-thread v0.1.3
tokio-dns-unofficial v0.3.1
tokio-executor v0.1.5 
tokio-fs v0.1.3
tokio-proto v0.1.1
tokio-io v0.1.7
tokio-threadpool v0.1.5
tokio-reactor v0.1.6
tokio-udp v0.1.1
tokio-uds v0.2.2
tokio-tcp v0.1.0
tokio-timer v0.2.7
tokio-tls v0.2.0
tokio-tungstenite v0.6.0

Platform

Darwin Kernel Version 16.7.0: Thu Jun 21 20:07:39 PDT 2018; root:xnu-3789.73.14~1/RELEASE_X86_64 x86_64

Subcrates

tokio-reactor = "0.1.6"
tokio-retry = "0.2"
tokio-timer = "0.2.7"

Description

Tokio::runtime::Runtime::block_on does not work as expected. For my use case it would be great if it could be used similarly to tokio::run. I am replacing tokio::run in order to allow the entire runtime to shutdown gracefully if a panic occurs in a spawned future.

I tried this

runtime.block_on(future::lazy(|| main()))

which returned: error on unwrap: 'Value: Canceled' suggesting that the oneshot sender created in block_on was getting dropped early. I also saw SpawnError {shutdown: is_true} during development.
I eventually was successful by using tokio_executor::with_default() to set the executor as the default for the runtime context. I then experienced similar errors for timer when I tried to implement a timeout(); this required the same solution, tokio_timer::with_default(). In the end I am not using runtime::block_on directly instead using tokio_executor::Enter::block_on() within the context of default reactor, executor, and timer that I set up.
It would be great to have something similar to block_on that sets these defaults, or a way to easily create the defaults through the runtime rather then bringing in tokio_executor, tokio_reactor, and tokio_timer for access to their with_default methods...or some clear documentation in block_on hinting at the lack of defaults and where that could cause problems within the runtime context.

Sample runtime context setup with defaults for ::block_on

https://github.com/graphprotocol/graph-node/blob/ford/tokio-blockon/node/src/main.rs#L67

[carllerche]

I'm looking at block_on and it looks like it should have access to everything. Could you provide a minimal repro that I can run to see the problem?

The future gets spawned onto the runtime, which should have everything configured (code).

[carllerche]

Closing cue to inactivity.