Stream: git-wasmtime

Topic: wasmtime / PR #14335 Add support for the compact imports ...

Wasmtime GitHub notifications bot (Sep 14 2026 at 22:15):

chacailline opened PR #14335 from chacailline:compact-imports to bytecodealliance:main:

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Adds support for the compact imports proposal, part of #14108.

Adds:

• Config::wasm_compact_imports option, default false
• CLI, TOML, and C/C++ API configuration options
• WAST test covering both types of compact imports
• Documentation updates

Waiting on 1 week of fuzzer runs to move the proposal to tier 1 and enable the proposal by default.

Please let me know if anything else needs to be added.

Wasmtime GitHub notifications bot (Sep 14 2026 at 22:15):

chacailline requested fitzgen for a review on PR #14335.

Wasmtime GitHub notifications bot (Sep 14 2026 at 22:15):

chacailline requested wasmtime-fuzz-reviewers for a review on PR #14335.

Wasmtime GitHub notifications bot (Sep 14 2026 at 22:15):

chacailline requested wasmtime-core-reviewers for a review on PR #14335.

Wasmtime GitHub notifications bot (Sep 14 2026 at 22:15):

chacailline requested wasmtime-default-reviewers for a review on PR #14335.

Wasmtime GitHub notifications bot (Sep 14 2026 at 23:44):

github-actions[bot] added the label fuzzing on PR #14335.

Wasmtime GitHub notifications bot (Sep 14 2026 at 23:44):

github-actions[bot] added the label wasmtime:api on PR #14335.

Wasmtime GitHub notifications bot (Sep 14 2026 at 23:44):

github-actions[bot] added the label wasmtime:c-api on PR #14335.

Wasmtime GitHub notifications bot (Sep 14 2026 at 23:44):

github-actions[bot] added the label wasmtime:docs on PR #14335.

Wasmtime GitHub notifications bot (Sep 14 2026 at 23:44):

github-actions[bot] added the label wasmtime:config on PR #14335.

Wasmtime GitHub notifications bot (Sep 14 2026 at 23:44):

github-actions[bot] commented on PR #14335:

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Wasmtime GitHub notifications bot (Sep 15 2026 at 01:12):

github-actions[bot] commented on PR #14335:

Label Messager: wasmtime:config

It looks like you are changing Wasmtime's configuration options. Make sure to
complete this check list:

• [ ] If you added a new Config method, you wrote extensive documentation for
  it.

  <details>

  Our documentation should be of the following form:

  ```text
  Short, simple summary sentence.

  More details. These details can be multiple paragraphs. There should be
  information about not just the method, but its parameters and results as
  well.

  Is this method fallible? If so, when can it return an error?

  Can this method panic? If so, when does it panic?

  Example

  Optional example here.
  ```

  </details>

• [ ] If you added a new Config method, or modified an existing one, you
  ensured that this configuration is exercised by the fuzz targets.

  <details>

  For example, if you expose a new strategy for allocating the next instance
  slot inside the pooling allocator, you should ensure that at least one of our
  fuzz targets exercises that new strategy.

  Often, all that is required of you is to ensure that there is a knob for this
  configuration option in [wasmtime_fuzzing::Config][fuzzing-config] (or one
  of its nested structs).

  Rarely, this may require authoring a new fuzz target to specifically test this
  configuration. See [our docs on fuzzing][fuzzing-docs] for more details.

  </details>

• [ ] If you are enabling a configuration option by default, make sure that it
  has been fuzzed for at least two weeks before turning it on by default.

[fuzzing-config]: https://github.com/bytecodealliance/wasmtime/blob/ca0e8d0a1d8cefc0496dba2f77a670571d8fdcab/crates/fuzzing/src/generators.rs#L182-L194
[fuzzing-docs]: https://docs.wasmtime.dev/contributing-fuzzing.html

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Wasmtime GitHub notifications bot (Sep 15 2026 at 20:12):

chacailline commented on PR #14335:

New config method has documentation in line with other feature config functions.

In local fuzzing runs, instantiate generated compact import statements. I think other ones that use wasm-smith should as well.

Config is off by default pending fuzzing. Btw docs Wasm Proposals says 1 week of fuzzing, but reminder bot says 2 weeks.

Wasmtime GitHub notifications bot (Sep 16 2026 at 21:39):

:memo: fitzgen submitted PR review:

LGTM, modulo two minor things below. Thanks!

Wasmtime GitHub notifications bot (Sep 16 2026 at 21:39):

:speech_balloon: fitzgen created PR review comment:

Does the spec testsuite not cover compact imports? I would have expected that we also enable running the spec tests for compact imports somewhere in crates/test-util/src/wast.rs or something.

Wasmtime GitHub notifications bot (Sep 16 2026 at 21:39):

:speech_balloon: fitzgen created PR review comment:

The [proposal] link is not actually used in the docs above, but should be.

We should a short paragraph summary of what the proposal actually is/enables here as well, similar to other Wasm proposal knobs.

Wasmtime GitHub notifications bot (Sep 22 2026 at 19:32):

chacailline updated PR #14335.

Wasmtime GitHub notifications bot (Sep 22 2026 at 20:10):

chacailline updated PR #14335.

Wasmtime GitHub notifications bot (Sep 22 2026 at 20:23):

chacailline commented on PR #14335:

I've updated the config documentation.

As of last week, the spec tests do have compact-imports tests. I updated the submodule revision and configured features for new tests.

One of the compact import tests currently fails because we reject zero-length compact import encoding groups. bytecodealliance/wasm-tools#2664 should fix that once Wasmtime uses a version of wasm-tools with the change.

I'm not really sure what to do with the other test failures.

Wasmtime GitHub notifications bot (Sep 22 2026 at 20:24):

chacailline edited a comment on PR #14335:

I've updated the config documentation.

As of last week, the spec tests do have compact-imports tests. I updated the submodule revision and configured features for new tests.

One of the compact import tests currently fails because we reject zero-length compact import encoding groups. bytecodealliance/wasm-tools#2664 should fix that once Wasmtime uses a version of wasm-tools with the change.

I'm not really sure what to do with the other test failures. Looks like type-subtyping and some extended-name-section tests are giving errors, but I'm not familiar with either.

Wasmtime GitHub notifications bot (Sep 22 2026 at 20:25):

chacailline edited a comment on PR #14335:

I've updated the config documentation.

As of last week, the spec tests do have compact-imports tests. I updated the submodule revision and configured features for new tests.

Some of the compact import tests currently fail because we reject zero-length compact import encoding groups. bytecodealliance/wasm-tools#2664 should fix that once Wasmtime uses a version of wasm-tools with the change.

I'm not really sure what to do with the other test failures. Looks like type-subtyping and some extended-name-section tests are giving errors, but I'm not familiar with either.

Wasmtime GitHub notifications bot (Sep 22 2026 at 20:52):

alexcrichton commented on PR #14335:

Can you flag all those tests somewhere around in this function as "should fail"? Those are mostly expected failures for now and we'll get them fixed when the proposals are fully implemented.

Wasmtime GitHub notifications bot (Sep 23 2026 at 02:33):

chacailline updated PR #14335.

Wasmtime GitHub notifications bot (Sep 23 2026 at 02:48):

chacailline updated PR #14335.

Wasmtime GitHub notifications bot (Sep 23 2026 at 22:32):

:thumbs_up: fitzgen submitted PR review:

Thansk!

Wasmtime GitHub notifications bot (Sep 23 2026 at 22:33):

fitzgen added PR #14335 Add support for the compact imports proposal to the merge queue.

Wasmtime GitHub notifications bot (Sep 23 2026 at 23:09):

:check: fitzgen merged PR #14335.

Wasmtime GitHub notifications bot (Sep 23 2026 at 23:09):

fitzgen removed PR #14335 Add support for the compact imports proposal from the merge queue.

Last updated: Oct 11 2026 at 04:10 UTC