Upgrading deno_std to v0.3.4 fails

[ry]

denoland/std#297

It hangs after 19 minutes and prints "WARNING the sharedQueue overflowed"
(The warning isn't necessarily a bad thing but is perhaps a hint)

[bartlomieju]

I've just encountered the same error when running deno --fmt, it hangs during compilation of prettier/main.ts.

Note that prettier requires large files.

$ ls deno_std/prettier/vendor
207K Feb  2 15:23 parser_babylon.js
126K Feb  2 15:23 parser_markdown.js
2.1M Mar 17 14:40 parser_typescript.js
965K Feb  2 15:23 standalone.js

EDIT: I'm debugging this

[bartlomieju]

@ry after some debugging I found that:

deno/core/isolate.rs

Line 393 in efe9c18

fn poll(&mut self) -> Poll<(), JSError> {

poll is not called again after we hit overflow_response.

So we're left in situation where there is 1 pending op but it's not resolved because poll is not called again.

Could you point me where should I dig further?

EDIT: I verified that by changing share queue size, still after queue overflows, poll is never called again and it just hangs.

[bartlomieju]

It seems that adding self.polled_recently = false; to unsuccessful_push branch resolves this issue.

if !successful_push {
  // If we couldn't push the response to the shared queue, because
  // there wasn't enough size, we will return the buffer via the
  // legacy route, using the argument of deno_respond.
  overflow_response = Some(buf);
  self.polled_recently = false;  // change
  break;
}

[ry]

Sounds like you figured it out! Try resetting polled_recently for that op.
Would be great to get a small test case that demoed this bug in core/isolate.rs test section.