Apply HMR updates in topological order #8752
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mischnic
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Jan 5, 2023
Benchmark ResultsKitchen Sink ✅
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Cold BundlesNo bundle changes detected. Cached BundlesNo bundle changes detected. AtlasKit Editor ✅
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Cold BundlesNo bundle changes detected. Cached BundlesNo bundle changes detected. Three.js ✅
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Cold BundlesNo bundle changes detected. Cached BundlesNo bundle changes detected. |
mischnic
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Jan 7, 2023
marcins
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Jul 14, 2023
* upstream/v2: (33 commits) v2.8.3 Changelog for v2.8.3 Address bug by updating an asset reference and merge conditions (parcel-bundler#8762) Fix CSS order when merging type change bundles (parcel-bundler#8766) fixing failing build for contributors on Linux using Node 18 (parcel-bundler#8763) Extension: Importers View and separate LSP protocol package (parcel-bundler#8747) Bump swc to fix sourcemaps with Windows line endings (parcel-bundler#8756) Apply HMR updates in topological order (parcel-bundler#8752) Make extension packaging work (parcel-bundler#8730) Typed api.storeResult (parcel-bundler#8732) Refactor LSP to use vscode-jsonrpc (parcel-bundler#8728) Bump swc (parcel-bundler#8742) Recursively check reachability when removing asset graphs from bundles in deduplication (parcel-bundler#6004) Fix tsc sourcemaps metadata (parcel-bundler#8734) Assigning to `this` in CommonJS (parcel-bundler#8737) Don't retarget dependencies if a symbol is imported multiple times with different local names (parcel-bundler#8738) Add a note about using flow in CONTRIBUTING.md (parcel-bundler#8731) filter out title execArgv to workers (parcel-bundler#8719) Document more of the BundleGraph class (parcel-bundler#8711) Fixed the hmr connection with host 0.0.0.0 (parcel-bundler#7357) ...
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This fixes an issue with circular dependencies and HMR. One example is if you had a React context provider, and a consumer that relied on it that was also a dependency of the provider, the context would become null after saving either of these components causing a crash.
In the test example, both of these components do not self accept the update because they don't only export React components (one exports a context, the other exports another function). Therefore, the update bubbles to the root App component which does accept it. However, the other modules still must be re-executed so they use the updated component. But since the dependency is circular,
consumer.jsre-executes first, and thenprovider.js. So that meansconsumer.jsis still pointing at an old version ofprovider.jswith the old context, which no longer has a value assigned to it.This PR fixes the issue by splitting the HMR accept phase into two:
Since we only re-execute the root-level accepting assets, but their children are already disposed, the children will be re-executed in topological order (the same as when first loading the asset). Splitting this into two phases also matches webpack's behavior more closely.