fix(save): keep lazy cache restore robust when a cached dep is absent#10065
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dmadisetti wants to merge 2 commits into
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fix(save): keep lazy cache restore robust when a cached dep is absent#10065dmadisetti wants to merge 2 commits into
dmadisetti wants to merge 2 commits into
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Three related fixes to the lazy-store restore path, extracted from the cache-e2e WASM validation work: - Restore tripwire: `_deserialize_blob` catches `ModuleNotFoundError` and binds the def as an `UnhashableStub` instead of aborting the whole restore — a torch tensor restored where torch is absent stays inert until touched, then raises a clear unhydratable error naming the def. The return value is excluded (a stubbed return fails the restore as a clean miss). Each def sharing a blob gets its own re-labeled stub. - Module-version pin survives restore: the pinned `__version__` captured at cache time is now persisted (`Item.module_version`) and replayed onto the `MissingModule` placeholder, so a version-pinned content hash reproduces on restore instead of collapsing to an empty version and missing. `hash.py` falls back to the in-scope placeholder when the module is not in `sys.modules`. `str()`-coerce the version because torch's `TorchVersion` is not encodable by the manifest codec. - Stale-key invalidation: `CacheState.stale_keys` + `Loader.mark_stale()` let a manifest be forced to miss for the session without being served or re-fetched (the WASM HTTP store would otherwise just re-fetch a cleared key). `save_cache` clears the mark so a recomputed value self-heals to a hit. No-op for loaders without a session-scoped store. Also resolves nested stubs on restore (an `ImmediateReferenceStub` whose blob is itself a `CustomStub`).
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This pull request was authored by a coding agent.
Follow-up to #9898 (merged). Three related fixes to the lazy-store restore path, extracted and hardened from WASM cache-restore validation (torch → KANNs demo). All three are independent robustness improvements to the save layer.
1. Restore tripwire
LazyLoader._deserialize_blobnow catchesModuleNotFoundErrorand binds the def as anUnhashableStubinstead of aborting the entire restore. A cached value whose codec needs an absent package (e.g. atorchtensor restored where torch isn't installed) stays inert until touched, then raises a clear unhydratable error naming the def. The return value is excluded — a stubbed return fails the restore as a clean miss. Each def sharing a blob (all UI vars shareui.pickle) gets its own re-labeled stub.2. Module-version pin survives restore
pin_modules=Truecaptured a module's__version__at cache time but discarded it on restore, so a version-pinned content hash recomputed tomodule:<ref>:and missed. The version is now persisted (Item.module_version) and replayed onto theMissingModuleplaceholder;hash.pyfalls back to the in-scope placeholder when the module isn't insys.modules. Version isstr()-coerced because torch'sTorchVersionisn't encodable by the manifest codec.3. Stale-key invalidation mechanism
Adds
CacheState.stale_keys+Loader.mark_stale()(no-op default): a manifest can be forced to miss for the session without being served or re-fetched. This is the primitive the cell-cache preflight (stacked PR #9895) needs — the WASM HTTP store would otherwise re-fetch a cleared key and re-hit the same unusable value in a loop.save_cacheclears the mark so a recomputed value self-heals to a hit.Also resolves nested stubs on restore (an
ImmediateReferenceStubwhose blob is itself aCustomStub).Test plan
tests/_save/loaders/test_lazy_wasm.py: newTestRestoreTripwire,TestModuleVersionPin,TestStaleKeys(42 pass)tests/_save/full suite: 327 pass🤖 Generated with Claude Code