JavaScript ShadowRealm proposal integration #9893
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This patch gives the TC39 JavaScript ShadowRealm proposal semantics in HTML. ShadowRealms are given an environment settings object; in general, ShadowRealms inherit their settings from the outer environment. When modules are used in ShadowRealms, module specifiers are interpreted with respect to the base URL of the surrounding environment, but when a module is imported within a ShadowRealm, it is a separate copy from what may be loaded in the surrounding environment or other ShadowRealms. This patch implements the plan described earlier at <tc39/proposal-shadowrealm#225 (comment)>. The ShadowRealm proposal is currently at Stage 2. Once this PR has been approved, it should be able to advance to Stage 3.
This avoids issues with ShadowRealms importing modules that the principal realm hasn't cached (yet).
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The changes to the module loading algorithms look ok.
For the record, we (people working on modules in TC39) have some ideas for splitting the stateless and stateful parts of Module Records in ECMA-262. If/once that will happen, it would be great to share a module map for the stateless parts across principal realms and shadow realms, so that basically in this case:
import "/foo";
new ShadowRealm().importValue("/foo", "bar");we only call into fetch once (to get the stateless part) and then we create the stateful part twice in both realms.
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I think this could benefit from review at this point |
Except for the timing. For discussion at TC39
Delete the Exposed attribute from AbortSignal.timeout, letting it inherit [Exposed=*] from AbortSignal. Cf. whatwg/html#9893 where other timers are being exposed in ShadowRealm global contexts.
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ShadowRealms reached 2.7 in TC39. Acceptance of this PR by WHATWG editors is a blocking requirement for Stage 3, though it probably shouldn't be landed until the Web API set is finalized. |
To replace #5339. Draft because I still need to iron out a few issues around module loading, and need to change what the global object looks like.
(See WHATWG Working Mode: Changes for more details.)
/browsing-the-web.html ( diff )
/dom.html ( diff )
/embedded-content.html ( diff )
/form-elements.html ( diff )
/index.html ( diff )
/infrastructure.html ( diff )
/media.html ( diff )
/nav-history-apis.html ( diff )
/references.html ( diff )
/scripting.html ( diff )
/structured-data.html ( diff )
/timers-and-user-prompts.html ( diff )
/webappapis.html ( diff )
/workers.html ( diff )