Loader.install should resolve pending imports

[matthewp]

This was a bug in the old spec and appears to still be present. Consider this code:

loader.import("main.js");

setTimeout(function(){
  loader.install("main.js", value);
}, 5);

This creates a race condition where if main.js passes through resolve before loader.install is called it will continue through the loading steps and (I believe) fail an assertion in linking.

Is loader.cancel intended to fix this issue?

[matthewp]

@caridy I think this should be labeled a bug. This problem means loader.install and loader.provide can only be safely used prior to any <module> tags or prior to any module loading having started. I'm not sure what their use-case would be if this were intentional and not a bug.

This same bug existed in the old System.set/System.define form and it made them effectively unusable.

[caridy]

I will look into the details next week.

[dherman]

This may have been fixed along the way as @caridy has been cleaning up the pipeline logic. He's currently working on a refactor of how the pipeline is represented (see PR #91). The semantics should be carefully ensuring there's only ever one promise stored for each stage, and we should only ever cancel an earlier stage's promise after a later stage has already been resolved. So I don't see off the top of my head how this bug would come up. But let's revisit it after the PR lands.

[caridy]

@matthewp this is now fixed (after PR #97).

[matthewp]

You meant "now fixed", right?

[caridy]

jejeje, yes! fixed.