Deps/opmsg

[fewf]

Hi @ry -- this is following up on #2223

Definitely not finished, but you can let me know if it's going in the right direction. I hacked modules into the ThreadSafeState object, so it can compile, but it's not behaving--I'm sure for obvious reasons. I'll leave some more comments around the code. Also thinking we'll need to add in some tests somewhere/

[fewf]

wasn't sure if this should be type string or not, since it could be arbitrarily large

[fewf]

this does not work right now

[fewf]

def want to come back and drop this any return type/create Interface for deps, etc

[bartlomieju]

I think you can easily take module name from message to allow to inspect any file:

Deno.deps("https://deno.land/log/mod.ts");

EDIT: One thing to keep in mind then is that fetch_module_meta_data_maybe_compile is used during boot, so it will print "Downloading" and "Compiling" messages

[ry]

I think you can easily take module name from message to allow to inspect any file:

I'm thinking about it, but it's not obvious to me how to find out which module as called an op... It seems this is some functionality we need in core.

[ry]

@fewf Sorry for the slow response! Good start on this - it's brought up a few questions

1. Using the main module as the referrer isn't correct - we need to somehow get the information about which module is calling an op. This is not obvious to me how to do this, but clearly would be very useful. I will research.
2. We need to move the modules from Worker into ThreadSafeState.

[ry]

This is something we need to do. However it needs to also be removed from the Worker struct. I will prepare a PR which does just this.

[bartlomieju]

Modules had been moved to State - @fewf you can merge latest changes from master

[ry]

After some research, it doesn't appear V8 gives us much in the way of determining which module called a function.

One way this might be accomplished is by manually traversing the current stack to figure out
It seems this could be determined is by calling v8::StackTrace::CurrentStackTrace(). It's not something we could do for every op, for performance reasons, but maybe it could be called during deps() or other ops that need it. Maybe something like const char* deno_calling_module(Deno* d) ...

[fewf]

Thanks for the info @ry. I think I understand the issue--it's that if A has B for a dependency and B calls deps, it should return only B's dependencies, right? That does seem tricky. I notice console.trace is not implemented in Deno--is that a todo? There's a way to get a stack trace like so (cribbed from https://stackoverflow.com/a/28118170 ):

  let stack;

  try {
    throw new Error('');
  }
  catch (error) {
    stack = error.stack || '';
  }

And that seems to work in Deno.

For the moment, I've pushed up some more proposed changes to better Typescript-ify the deps function and add the option to return an object instead of an array mentioned here #2096 (altho maybe that functionality should be elsewhere). I tried to rely on conventions I could find elsewhere.

[ry]

@fewf I'm closing stale PRs and I'm afraid this one qualifies. We've done a lot of refactoring in modules recently and I imagine this would need some strenuous rebasing. I'm going to close this - feel free to hit me up on gitter and discuss if you want to pursue. Sorry for not getting it in sooner - but there were some open questions.