Update 2020-12-30: we're not gonna upgrade to Tokio 0.3, but instead go straight to Tokio 1.0 (#8779), however we're still blocked by a few dependencies. Given that ResourceTable refactor eliminated most of the quirks/hangs and year is nearing the end I'm gonna close this issue as resolved.

Update 2020-12-17: rewrite of ResourceTable landed in #8512 and migration to Tokio 0.3 is in progress in #8779. That should
allow to close #8416 and most of issues listed in bugs.

Update 2020-11-23: we're on track with most of items listed in this issue and I hope we can wrap them up before end of the year. Unfortunately we won't be able to address some points from "features" and "maybe" so I'm dropping them from the list.

Here's the roadmap for cli and core for the last quarter of this year.

Refactors:

• finish compiler/bundler refactor (Refactoring how we compile code #7225, Refactor runtime compiler APIs #4752)
• finish TLA implementation fix: top-level-await module execution #7946
• refactor module loader in core (module resolve failed with dynamic import and circulated import #3736)
• rewrite ResourceTable (Refactor ResourceTable tracking issue #8416)

maybe

• refactor file fetcher infrastructure - resolve cache busting problem (bug(Worker): Not loading latest version of specified script #6116, Deno.bundle uses cache #5631, Compiler APIs should allow a reload option to cache bust #5253, others)
• finish op crates refactor - tests, remaining web APIs in crates
• rewrite "prepareStackTrace" API (Rewrite "prepareStackTrace" to use Rust API #7644)
• better error messages (using .context())

Bugs:

• harden subprocess implementation (Zombie subprocesses  #7087, bug: Windows hangs on double process.status() #3014, Awaiting stderr results in script hanging, sometimes #5621, [Question] Is It Possible to Write stdin to Sub Process Multiple Times? #7713, Getting Output from Deno.run Hangs If stdin is Not Closed #7727)
• harden workers implementation (Main thead panics upon worker thread panicing #7620, Deno Worker memory leak #6320, Panic when closing a worker immediately after postMessage #5334, Error stack in worker missing #4728)
• harden file watcher implementation (Deno.exit terminates entire process when using run --watch #7590, Watcher stucked into a infinite restart #7627)
• harden WS implementation (New WS api blocking after closing connection #7457)
• harden HTTPS server implementation (https connection times out #8107)

Features:

• MVP for "deno lsp" - provide minimal version of LSP that would replace logic in vscode_deno (deno lsp #8400)
• structured clone for workers (Structured clone should not fail silently, but instead throw a "not-implemented" error #6887)
• unref timers (Feature request: Support async unref for timers #6141)
• doctest support (feat: deno test --docs support #7916)
• deno compile (feat: deno compile #8539)
• provide library crate (Feature request: CLI available as library #7928, Rust library with batteries included #2633)
  maybe
• WASM imports (Bring back .wasm imports #5609)
• JSON imports (Import Assertions/JSON Modules #7623)
• extensible testing infrastructure ("test" output from deno test seems redundant #7840)

All of these are being worked on, and they tend to be at the complex end of the spectrum. If there are small bits where contribution can be easy, we will try to break it out as a separate issue.

Keep in mind this is a roadmap for the core team and contributors' proposals are currently not included in it. I'm more than happy to coordinate with contributors to include more propositions in the roadmap that would be tackled by the community.