[sbomer]

Extracts ILLink's experimental invocation cache into shared sources, compiled into each consumer without adding a shared DLL. Tasks provide invocation descriptions and prepare their outputs before executing; the shared engine handles content hashing, lookup, restoration, storage, and purge. This intentionally goes beyond a mechanical extraction: the common output contract supports owned directories and file sets, records absent outputs, and uses checksummed manifests. That changes the experimental v1 entry format: existing entries are not reused, but remain purgable. #135446 builds on this infrastructure to add crossgen2 caching.

Replaces the ILLink-specific maintenance package and command with dotnet-build-cache, shared by both caches. Existing users should install that package instead of dotnet-illink-cache and replace dotnet illink-cache purge ... with dotnet build-cache purge --cache illink .... Commands already selecting an explicit directory can use dotnet build-cache purge --cache-directory <path> ... without a cache name. The cache-enablement environment variables are unchanged.

Validated independently on this branch: 287 ILLink/shared-cache tests and 65 maintenance-tool tests passed. Modern .NET and net472 task builds passed; net472 was built but not executed on Linux.

Note

This content was created with assistance from AI.

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[Copilot]

🔵 Needs a closer look

Expanded filesystem restoration and incompatible cache encoding warrant maintainer validation across supported platforms; builds and tests were not rerun in this review.

No open issues 🎉

1 previously missed issue

In code that hasn't changed since last review

Update API sketch and lifecycle docs for current cache contract

docs/​design/​tools/​illink/​task-cache.md:36

The API sketch and lifecycle paragraph describe an integration that the shared cache no longer exposes. TryCreateFromEnvironment takes InvocationCacheConfiguration; ILLink calls ExecuteCached with an InvocationDescription callback and a parameterless execution callback; restore/store take InvocationOutputs. The shared engine now computes the key from the task's input inventory and context. Update the signatures and ownership explanation together so additional consumers do not follow the obsolete callback contract.

3 resolved since last review

• Prevent overlapping cache deletion on invalid output
• Avoid undocumented package and command renaming
• Preserve v1 format compatibility and defer format changes

_{Review effort: Balanced}

[Copilot]

🔵 Needs a closer look

The expanded cache format and destructive output-restoration contract warrant cross-platform maintainer review; builds and tests were not run in this review.

1 open issue

• Align API sketch and lifecycle explanation with implementation · New

_{Review effort: Balanced}

[Copilot]

🔵 Needs a closer look

The expanded storage and output-restoration contracts warrant human cross-platform validation, particularly because net472 was built but not executed.

No open issues 🎉

1 resolved since last review

• Align API sketch and lifecycle explanation with implementation

_{Review effort: Balanced}

[sbomer]

This change is extracting the ILLink cache logic to allow sharing sources. As part of that I'm starting to make the shared layer have a shape that could be adapted for use in MSBuild.

@agocke @rainersigwald I'm not trying to finalize the API details here, but would appreciate your input on the overall shape, with the goal of eventually moving this to MSBuild (possibly backed by a different cache storage engine later).

[sbomer]

/ba-g "Unrelated failures are dotnet/diagnostics#6143"