…=jonco

This patch implements tc39/ecma262#3715, to make

  import * as ns from "mod";
  export { ns };

behave the same as

  export * as ns from "mod";

Tested by tc39/test262#4606

Differential Revision: https://phabricator.services.mozilla.com/D274013

…=jonco

This patch implements tc39/ecma262#3715, to make

  import * as ns from "mod";
  export { ns };

behave the same as

  export * as ns from "mod";

Tested by tc39/test262#4606

Differential Revision: https://phabricator.services.mozilla.com/D274013

UltraBlame original commit: d14a908552e6d040c7538351430b3152a4a36887

…=jonco

This patch implements tc39/ecma262#3715, to make

  import * as ns from "mod";
  export { ns };

behave the same as

  export * as ns from "mod";

Tested by tc39/test262#4606

Differential Revision: https://phabricator.services.mozilla.com/D274013

UltraBlame original commit: d14a908552e6d040c7538351430b3152a4a36887

…=jonco

This patch implements tc39/ecma262#3715, to make

  import * as ns from "mod";
  export { ns };

behave the same as

  export * as ns from "mod";

Tested by tc39/test262#4606

Differential Revision: https://phabricator.services.mozilla.com/D274013

UltraBlame original commit: d14a908552e6d040c7538351430b3152a4a36887

https://bugs.webkit.org/show_bug.cgi?id=303141

Reviewed by Yusuke Suzuki and Sosuke Suzuki.

This patch changes JSC's handling of `import * as ns; export { ns }`
to align with tc39/ecma262#3715, which reached
consensus in the Nov 2025 TC39 meeting.

This will be tested by tc39/test262#4606, for
now I manually verified that the relevant tests in that PR are failing
before this patch and passing after it.

* Source/JavaScriptCore/parser/ModuleAnalyzer.cpp:
(JSC::ModuleAnalyzer::exportVariable):

Canonical link: https://commits.webkit.org/303952@main

This fixes a long standing issue where re-exported namespaces are not
disambiguated. If a namespace is re-exported in multiple dependencies,
then according to ecma262 this is not an ambiguous import.

Example:

                    export let x = 1
                        /       \
    export * as dep from ...    export * as dep from ...
                       \        /
                   export * from left
                   export * from right
                           |
                 import { dep } from ...
                 haz(dep.x)

While doing so we also implement the normative PR3715 [0] treating
`export * as dep from ...` the same as
`import * as dep from ...; export { dep }`.

Since modules can import themselves we must be able to produce a
shared binding cell to identify the namespace, before the namespace is
fully populated. To that end we store the namespace indirectly through
an additional binding cell in the module that we can use as a result
of the name resolution.

In other words in a module graph like

       export let x = 1
          |
       export * as dep from ...
          |
       import { dep } from ...

We will now resolve `{ dep }` to the special namespace binding cell on
the topmost module instead of the private re-export binding cell of the
middle module.

[0] tc39/ecma262#3715

Bug: 464065358
Change-Id: Ief31089987085772f92f3c32aecbf02db6796cee
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/7362765
Auto-Submit: Olivier Flückiger <olivf@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#104825}