"When you say "local to the evaluation context", what do you mean?"
Suppose you have an isolate with two contexts, C1 and C2, and a module whose evaluation produces side effects. Once you've evaluated the module in C1, there's no way to apply its side effects to C2. You can import it into C2, but doing so doesn't replicate the side effects. You can use its exports in C2, but they won't work correctly if they rely on the side effects. "The current API is designed to allow one evaluation per v8::Context" But it doesn't do that. It allows one evaluation per isolate. Evaluating a module in one context breaks it for others. On Wednesday, June 19, 2019 at 5:21:43 PM UTC-4, Adam Klein wrote: > > When you say "local to the evaluation context", what do you mean? Modules > can't have side-effects on the lexical top-level scope of the importing > module; they can only affect the broader "realm" (in ECMAScript spec > terms), the v8::Context (in V8 API terms) or the mutable global state (in > more common terms). The current API is designed to allow one evaluation per > v8::Context, since part of Instantiation > <https://cs.chromium.org/chromium/src/v8/include/v8.h?rcl=ab5fb228bcaf387cc72dfd93cdc62c1db4867ebf&l=1302> > > is tying a v8::Module to a v8::Context. So if you instantatiate a module in > multiple context, multiple evaluations should still work. > > On Thu, Jun 13, 2019 at 7:12 AM ClearScript Developers < > clearsc...@gmail.com <javascript:>> wrote: > >> Sorry to revive this thread, but we're encountering the same issue. >> >> v8::Script is not a replacement for v8::Module; for one thing, scripts >> can't import modules :) >> >> In any case, V8's API seems deficient here. Modules can be imported >> specifically for their side effects. There's even unique syntax for that >> (see >> https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import#Import_a_module_for_its_side_effects_only). >> >> And since side effects can be local to the evaluation context, it should be >> possible to evaluate a module in multiple contexts. >> >> Opinions? >> >> On Wednesday, February 20, 2019 at 2:54:26 PM UTC-5, Adam Klein wrote: >>> >>> Modules are designed (in the JavaScript spec) to only have their >>> top-level code run once. To "re-use" a cached module, the expectation is >>> that other modules would use imports to access the exports of that module. >>> In particular, in your code snippet, you'd return the already-evaluated >>> module from the ResolveCallback passed to the module that wishes to import >>> from it. >>> >>> If what you want to do is compile some code and run it multiple times, a >>> v8::Script is probably want you want instead. >>> >>> On Tue, Feb 12, 2019 at 5:11 PM Jane Chen <jxch...@gmail.com> wrote: >>> >>>> Embedding v8 6.7. >>>> >>>> I found the following test in test-modules.cc: >>>> >>>> CHECK(module->Evaluate(env.local()) >>>> .ToLocalChecked() >>>> ->StrictEquals(v8_str("gaga"))); >>>> CHECK_EQ(Module::kEvaluated, module->GetStatus()); >>>> >>>> CHECK(module->Evaluate(env.local()).ToLocalChecked()->IsUndefined()); >>>> >>>> and it is consistent with what I'm seeing. Basically, evaluating an >>>> evaluated module returns undefined. I don't get the rational for this >>>> behavior. Once a module is evaluated, it is no good for evaluation? Then >>>> how am I supposed to re-use a cached module? Re-instantiating it doesn't >>>> seem to help. >>>> >>>> -- >>>> -- >>>> v8-users mailing list >>>> v8-u...@googlegroups.com >>>> http://groups.google.com/group/v8-users >>>> --- >>>> You received this message because you are subscribed to the Google >>>> Groups "v8-users" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to v8-u...@googlegroups.com. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> -- >> -- >> v8-users mailing list >> v8-u...@googlegroups.com <javascript:> >> http://groups.google.com/group/v8-users >> --- >> You received this message because you are subscribed to the Google Groups >> "v8-users" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to v8-u...@googlegroups.com <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/v8-users/a7260cfa-cc60-4870-b11d-b2d00c79eb01%40googlegroups.com >> >> <https://groups.google.com/d/msgid/v8-users/a7260cfa-cc60-4870-b11d-b2d00c79eb01%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. 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