perf(cargo-anvil): parallelize Miri test artifacts

[st-dev-gh]

Summary

• Compile each selected Miri profile once, preserving workspace feature unification.
• Run independent test artifacts concurrently through cargo-miri runner, defaulting to one worker per logical processor with an ANVIL_MIRI_JOBS override.
• Add package-level Miri exclusions, grouped GitHub and Azure DevOps output, and aggregated artifact failures.
• Apply the updated cargo-anvil templates to this repository.

This brings the generic Miri orchestration developed in microsoft/oxidizer#706 into cargo-anvil. Repository-specific workload reductions and artifact priorities remain outside cargo-anvil.

Behavior

The four scheduled Miri profiles remain sequential. Within each profile, Cargo compiles the selected scope once with --no-run, and only Cargo artifacts marked profile.test = true are executed concurrently.

Packages can exclude their own test targets while remaining available as dependencies:

[package.metadata.anvil.miri]
exclude = true

ANVIL_MIRI_JOBS accepts a positive integer override.

Validation

• Full cargo-anvil test suite
• Repository spellcheck
• Byte-exact generated-output snapshots for local, GitHub, and Azure DevOps backends
• Clean cargo anvil --dry-run after applying the templates
• Real Miri smoke run with two concurrent test artifacts

[Copilot]

Pull request overview

This PR upgrades the cargo-anvil Miri check implementation to compile the selected workspace scope once and then execute discovered profile.test = true libtest artifacts concurrently via cargo-miri runner, with deterministic log replay and aggregated failures. It also adds a package-level opt-out knob ([package.metadata.anvil.miri] exclude = true) and applies the updated templates to this repository, including documentation and snapshot updates.

Changes:

• Add a shared _anvil-miri-test Just recipe that compiles once (--no-run), discovers test artifacts from Cargo JSON, and runs them in parallel with ANVIL_MIRI_JOBS controlling concurrency.
• Update all Miri profiles (miri, miri-tree-borrows, miri-strict-provenance, miri-race-coverage) to delegate execution to the shared runner and preserve profile-specific flags.
• Extend cargo-anvil contract tests/docs/snapshots and update .anvil.lock to reflect regenerated template outputs.

Reviewed changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
justfiles/anvil/checks/miri.just	Introduces _anvil-miri-test and routes anvil-miri through the shared parallel artifact runner.
justfiles/anvil/checks/miri-tree-borrows.just	Delegates Tree Borrows profile execution to _anvil-miri-test.
justfiles/anvil/checks/miri-strict-provenance.just	Delegates Strict Provenance profile execution to _anvil-miri-test.
justfiles/anvil/checks/miri-race-coverage.just	Delegates Race Coverage profile execution to _anvil-miri-test.
crates/cargo-anvil/templates/justfiles/anvil/checks/miri.just	Template source for the new shared parallel Miri artifact runner.
crates/cargo-anvil/templates/justfiles/anvil/checks/miri-tree-borrows.just	Template updated to call the shared runner.
crates/cargo-anvil/templates/justfiles/anvil/checks/miri-strict-provenance.just	Template updated to call the shared runner.
crates/cargo-anvil/templates/justfiles/anvil/checks/miri-race-coverage.just	Template updated to call the shared runner.
crates/cargo-anvil/src/lib.rs	Updates public crate documentation to describe compile-once + parallel artifact execution, plus package opt-out metadata.
crates/cargo-anvil/docs/design/local.md	Documents the new Miri concurrency model and the package-level exclude metadata.
crates/cargo-anvil/docs/design/checks.md	Updates the miri check contract to match the new artifact runner behavior and profile delegation.
crates/cargo-anvil/src/anvil/artifacts/justfile.rs	Adds a regression test ensuring Miri profiles delegate to the shared runner and key behaviors are present in the generated check file bodies.
crates/cargo-anvil/tests/recipe_contracts.rs	Adds contract tests with a fake cargo miri/cargo-miri runner to validate exclusion logic, parallelism, flag propagation, and failure aggregation.
crates/cargo-anvil/tests/snapshots/snapshots__local_only.snap	Updates expected generated output snapshot to include _anvil-miri-test and delegation.
crates/cargo-anvil/tests/snapshots/snapshots__github_backend.snap	Updates expected generated output snapshot to include _anvil-miri-test and delegation.
crates/cargo-anvil/tests/snapshots/snapshots__ado_backend.snap	Updates expected generated output snapshot to include _anvil-miri-test and delegation.
crates/cargo-anvil/README.md	Regenerated README content reflecting the updated Miri behavior and metadata opt-out.
.anvil.lock	Updates catalog checksum and file/region checksums for regenerated Anvil-managed files.

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[Copilot]

Pull request overview

Copilot reviewed 17 out of 18 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 17 out of 18 changed files in this pull request and generated no new comments.

Suppressed comments (1)

justfiles/anvil/checks/miri.just:177

• The PR description claims “memory telemetry”, but this runner currently doesn’t emit any memory usage/pressure info (it only prints artifact/job counts). Either add explicit telemetry (and document what it measures) or adjust the PR description so it doesn’t promise this behavior.

        Write-Host "anvil miri: running $($artifacts.Count) test artifacts with $jobs concurrent process(es)"

[Codecov Comments Bot (codecov-commenter)]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.5%. Comparing base (7a5daf3) to head (9bf220d).
⚠️ Report is 1 commits behind head on main.

❌ Your project status has failed because the head coverage (97.5%) is below the target coverage (100.0%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #123     +/-   ##
=======================================
- Coverage   97.5%   97.5%   -0.1%     
=======================================
  Files        300     300             
  Lines      67799   67799             
=======================================
- Hits       66160   66154      -6     
- Misses      1639    1645      +6     

Flag	Coverage Δ
linux	97.5% <ø> (-0.1%)	⬇️
linux-arm	97.5% <ø> (-0.1%)	⬇️
scheduled	?
windows	97.7% <ø> (ø)

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[Sander Saares (sandersaares)]

[Copilot speaking]

Published 19 findings. No finding follows up on an existing discussion thread.

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Diagnostic	Value
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[martin-kolinek]

🤖: Approved.

[Copilot]

Pull request overview

Copilot reviewed 17 out of 18 changed files in this pull request and generated 2 comments.

[Copilot]

🟡 Changes recommended

The new _anvil-miri-test runner uses rustc ... --print sysroot output as a scalar, which can break if PowerShell captures multiple lines/arrays; the sysroot parsing should be made robust (comments added in both miri.just copies).

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

• Files reviewed: 17/18 changed files
• Comments generated: 2
• Review effort level: Lite

[Copilot]

🔵 Needs a closer look

It substantially changes the CI-critical Miri execution model (parallel artifact orchestration, filtering, and log replay) and should receive final human review despite strong test coverage.

Review details

• Files reviewed: 21/22 changed files
• Comments generated: 0 new
• Review effort level: Lite

[Copilot]

🟡 Changes recommended

The Miri exclusion-to---exclude argument construction iterates a HashSet, producing non-deterministic cargo argument ordering that should be stabilized.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

• Files reviewed: 22/23 changed files
• Comments generated: 1
• Review effort level: Lite

[Copilot]

🟢 Approval recommended

The implementation, templates, docs, snapshots, and contract/structural tests are consistently updated to the new parallel Miri execution model with no verified correctness issues in the reviewed diffs.

Review details

• Files reviewed: 22/23 changed files
• Comments generated: 0 new
• Review effort level: Lite