[BobClawblaw]

What this changes

Three tests in zig/src/native/draft_sources_metal_test.zig call the Metal Qwen27 lanes' facts() with the runner left undefined. Since #1125, facts() reads runner.model.config.moe(), so the first of them crashed zig build test-native with SIGSEGV on main. Each test now points the runner at a model with a dense config (experts = 0). The first also checks that plain_guard is off for that config and on once the config has routed experts. Only the tests change; the engine does not.

• Issue: Fixes test-native crashes in the Metal Qwen27 lanes' draft-sources tests #2121
• Stacked on: main (b331731e6)
• atc overlap --json: one open pull request touches the same file, lfm2: DSpark drafting with owned context and confidence scheduling #1394 (LFM2 DSpark drafting), and merges cleanly with this one. Coverage was incomplete (pullFilesLimit), so I also checked the file lists of all open pull requests by hand: lfm2: DSpark drafting with owned context and confidence scheduling #1394 is the only one touching zig/src/native/draft_sources_metal_test.zig.

Checks on this head

• Head commit: a103069ac
• zig build test-native: passes on M5 Ultra, macOS, Zig 0.17.0. On main b331731e6 it crashes in this test with SIGSEGV. With facts() mutated to ignore the config (routed = false), the test fails on the plain_guard check.
• zig fmt --check, lean (lean_new.py): pass; lean is 425 on the base and 425 on this head, 0 new
• Not run, and why: the rest of the CI set locally (zig build test, golden, the contract); the change is one test file that only test-native builds, and CI runs the rest.

Receipt

n/a: tests only, no served path changes.

Checklist

• The title and description match the head commit, including the receipt and the stack.
• New tests fail before the change, pass after it, and skip cleanly without their dependency. (The crash is the failure before; the plain_guard check fails if facts() stops reading the config.)
• Comments and docstrings are one line. No measurements or history in the source.
• No personal data, machine names, internal hosts or local paths in the diff or its commits. No AI attribution lines.

[ashhart]

Thanks @BobClawblaw. Pointing the runner at a dense config fixes the crash, and checking plain_guard both ways makes the test catch facts() ignoring the config. Ready to land.

[ashhart]

Thank you @BobClawblaw. This is merged into main with your commits under your own name, so you're listed as a TensorFold contributor. It ships in the next release, credited to you in the changelog and the release notes.

[ashhart]

Thanks @BobClawblaw! This is in TensorFold 1.2.3, out now: https://github.com/ashhart/TensorFold/releases/tag/v1.2.3