wasmtime / PR #14891 [DO NOT REVIEW] Avoid collisions bet... · git-wasmtime

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Topic: wasmtime / PR #14891 [DO NOT REVIEW] Avoid collisions bet...

Wasmtime GitHub notifications bot (Oct 20 2026 at 22:47):

jrandolf opened PR #14891 from jrandolf:bindgen-name-collisions-shared to bytecodealliance:main:

This builds on #14867, so only the last commit is new here. It fixes the rest of #14856: labels and other names in a world clashing with the names bindgen! generates.

In review of #14867 the suggestion was that bindgen! should generate bindings that can represent any valid WIT, rather than detecting clashes and erroring. This does that. All the names generated for a world's imports and exports are now chosen in one place, WorldNames, before any bindings are generated. That covers:

the root and exports modules,

the world struct's accessors and call_*/func_* methods,

its fields.

When two names would collide, the one claimed later gets a trailing _. The order is fixed and documented in a new "Generated names" section of the bindgen! docs: reserved names first (exports, named_imports, new, instantiate, ...), then namespaces and plain exports, then exported functions, then labels. Names that don't collide stay the same, so none of the existing expanded snapshots change.

Some examples, in package foo:foo:

WIT Generated

export foo: greeter; + export greeter; exports::foo_ with accessor foo(), next to exports::foo::foo::greeter

export foo-foo-greeter: greeter; + export greeter; accessors foo_foo_greeter_() and foo_foo_greeter()

export new: interface {} accessor new_()

export call-run: interface {} + export run: func(); call_run() for the function, call_run_() for the label

import foo: interface { ... } module foo_, next to the namespace foo

import exports: interface { ... } module exports__

While here, this also fixes keyword escaping for uppercase names like TYPE and for keyword namespaces and packages (package %use:%fn), which produced invalid identifiers in the same places.

The new name-collisions.wit codegen test covers these. Without this change, the macro panics on it or the output fails to compile.

Closes #14856

WIT	Generated
`export foo: greeter;` + `export greeter;`	`exports::foo_` with accessor `foo()`, next to `exports::foo::foo::greeter`
`export foo-foo-greeter: greeter;` + `export greeter;`	accessors `foo_foo_greeter_()` and `foo_foo_greeter()`
`export new: interface {}`	accessor `new_()`
`export call-run: interface {}` + `export run: func();`	`call_run()` for the function, `call_run_()` for the label
`import foo: interface { ... }`	module `foo_`, next to the namespace `foo`
`import exports: interface { ... }`	module `exports__`

Wasmtime GitHub notifications bot (Oct 21 2026 at 00:29):

jrandolf updated PR #14891.

Wasmtime GitHub notifications bot (Oct 21 2026 at 02:52):

github-actions[bot] added the label wasmtime:api on PR #14891.

Wasmtime GitHub notifications bot (Oct 21 2026 at 18:23):

jrandolf updated PR #14891.

Wasmtime GitHub notifications bot (Oct 21 2026 at 18:31):

jrandolf edited PR #14891:

This fixes the rest of #14856: labels and other names in a world clashing with the names bindgen! generates.

In review of #14867 the suggestion was that bindgen! should generate bindings that can represent any valid WIT, rather than detecting clashes and erroring. This does that. All the names generated for a world's imports and exports are now chosen in one place, WorldNames, before any bindings are generated. That covers:

the root and exports modules,

the world struct's accessors and call_*/func_* methods,

its fields.

When two names would collide, the one claimed later gets a trailing _. The order is fixed and documented in a new "Generated names" section of the bindgen! docs: reserved names first (exports, named_imports, new, instantiate, ...), then namespaces and plain exports, then exported functions, then labels. Names that don't collide stay the same, so none of the existing expanded snapshots change.

Some examples, in package foo:foo:

WIT Generated

export foo: greeter; + export greeter; exports::foo_ with accessor foo(), next to exports::foo::foo::greeter

export foo-foo-greeter: greeter; + export greeter; accessors foo_foo_greeter_() and foo_foo_greeter()

export new: interface {} accessor new_()

export call-run: interface {} + export run: func(); call_run() for the function, call_run_() for the label

import foo: interface { ... } module foo_, next to the namespace foo

import exports: interface { ... } module exports__

While here, this also fixes keyword escaping for uppercase names like TYPE and for keyword namespaces and packages (package %use:%fn), which produced invalid identifiers in the same places.

The new name-collisions.wit codegen test covers these. Without this change, the macro panics on it or the output fails to compile.

Closes #14856

WIT	Generated
`export foo: greeter;` + `export greeter;`	`exports::foo_` with accessor `foo()`, next to `exports::foo::foo::greeter`
`export foo-foo-greeter: greeter;` + `export greeter;`	accessors `foo_foo_greeter_()` and `foo_foo_greeter()`
`export new: interface {}`	accessor `new_()`
`export call-run: interface {}` + `export run: func();`	`call_run()` for the function, `call_run_()` for the label
`import foo: interface { ... }`	module `foo_`, next to the namespace `foo`
`import exports: interface { ... }`	module `exports__`

Wasmtime GitHub notifications bot (Oct 21 2026 at 18:41):

jrandolf has marked PR #14891 as ready for review.

Wasmtime GitHub notifications bot (Oct 21 2026 at 18:41):

jrandolf removed the review request for wasmtime-core-reviewers from PR #14891.

Wasmtime GitHub notifications bot (Oct 21 2026 at 18:41):

jrandolf requested wasmtime-core-reviewers for a review on PR #14891.

Wasmtime GitHub notifications bot (Oct 21 2026 at 18:41):

jrandolf requested pchickey for a review on PR #14891.

Last updated: Oct 31 2026 at 23:03 UTC