[Flight] Fallback to importing the whole module instead of encoding every name #26624
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facebook-github-bot
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gnoff
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Apr 14, 2023
kassens
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Apr 17, 2023
…very name (facebook#26624) We currently don't just "require" a module by its module id/path. We encode the pair of module id/path AND its export name. That's because with module splitting, a single original module can end up in two or more separate modules by name. Therefore the manifest files need to encode how to require the whole module as well as how to require each export name. In practice, we don't currently use this because we end up forcing Webpack to deopt and keep it together as a single module, and we don't even have the code in the Webpack plugin to write separate values for each export name. The problem is with CJS we don't statically know what all the export names will be. Since these cases will never be module split, we don't really need to know. This changes the Flight requires to first look for the specific name we're loading and then if that name doesn't exist in the manifest we fallback to looking for the `"*"` name containing the entire module and look for the name in there at runtime. We could probably optimize this a bit if we assume that CJS modules on the server never get built with a name. That way we don't have to do the failed lookup. Additionally, since we've recently merged filepath + name into a single string instead of two values, we now have to split those back out by parsing the string. This is especially unfortunate for server references since those should really not reveal what they are but be a hash or something. The solution might just be to split them back out into two separate fields again. cc @shuding
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Jun 13, 2023
Both of our bundlers won't split different exports of a module into different chunks, we can rely on facebook/react#26624 to simplify the structure. This reduces the size of the client reference manifest by ~70%.
EdisonVan
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Apr 15, 2024
…very name (facebook#26624) We currently don't just "require" a module by its module id/path. We encode the pair of module id/path AND its export name. That's because with module splitting, a single original module can end up in two or more separate modules by name. Therefore the manifest files need to encode how to require the whole module as well as how to require each export name. In practice, we don't currently use this because we end up forcing Webpack to deopt and keep it together as a single module, and we don't even have the code in the Webpack plugin to write separate values for each export name. The problem is with CJS we don't statically know what all the export names will be. Since these cases will never be module split, we don't really need to know. This changes the Flight requires to first look for the specific name we're loading and then if that name doesn't exist in the manifest we fallback to looking for the `"*"` name containing the entire module and look for the name in there at runtime. We could probably optimize this a bit if we assume that CJS modules on the server never get built with a name. That way we don't have to do the failed lookup. Additionally, since we've recently merged filepath + name into a single string instead of two values, we now have to split those back out by parsing the string. This is especially unfortunate for server references since those should really not reveal what they are but be a hash or something. The solution might just be to split them back out into two separate fields again. cc @shuding
bigfootjon
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Apr 18, 2024
…very name (#26624) We currently don't just "require" a module by its module id/path. We encode the pair of module id/path AND its export name. That's because with module splitting, a single original module can end up in two or more separate modules by name. Therefore the manifest files need to encode how to require the whole module as well as how to require each export name. In practice, we don't currently use this because we end up forcing Webpack to deopt and keep it together as a single module, and we don't even have the code in the Webpack plugin to write separate values for each export name. The problem is with CJS we don't statically know what all the export names will be. Since these cases will never be module split, we don't really need to know. This changes the Flight requires to first look for the specific name we're loading and then if that name doesn't exist in the manifest we fallback to looking for the `"*"` name containing the entire module and look for the name in there at runtime. We could probably optimize this a bit if we assume that CJS modules on the server never get built with a name. That way we don't have to do the failed lookup. Additionally, since we've recently merged filepath + name into a single string instead of two values, we now have to split those back out by parsing the string. This is especially unfortunate for server references since those should really not reveal what they are but be a hash or something. The solution might just be to split them back out into two separate fields again. cc @shuding DiffTrain build for commit da6c23a.
sebmarkbage
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Sep 13, 2024
In #26624, the ability to mark a client reference module as `async` in the React client manifest was removed because it was not utilized by Webpack, neither in `ReactFlightWebpackPlugin` nor in Next.js. However, some bundlers and frameworks are sophisticated enough to properly handle and identify async ESM modules (e.g., client component modules with top-level `await`), most notably Turbopack in Next.js. Therefore, we need to consider the `async` flag in the client manifest when resolving the client reference metadata on the server. The SSR manifest cannot override this flag, meaning that if a module is async, it must remain async in all client environments. x-ref: vercel/next.js#70022
github-actions bot
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Sep 13, 2024
In #26624, the ability to mark a client reference module as `async` in the React client manifest was removed because it was not utilized by Webpack, neither in `ReactFlightWebpackPlugin` nor in Next.js. However, some bundlers and frameworks are sophisticated enough to properly handle and identify async ESM modules (e.g., client component modules with top-level `await`), most notably Turbopack in Next.js. Therefore, we need to consider the `async` flag in the client manifest when resolving the client reference metadata on the server. The SSR manifest cannot override this flag, meaning that if a module is async, it must remain async in all client environments. x-ref: vercel/next.js#70022 DiffTrain build for [5deb782](5deb782)
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We currently don't just "require" a module by its module id/path. We encode the pair of module id/path AND its export name. That's because with module splitting, a single original module can end up in two or more separate modules by name. Therefore the manifest files need to encode how to require the whole module as well as how to require each export name.
In practice, we don't currently use this because we end up forcing Webpack to deopt and keep it together as a single module, and we don't even have the code in the Webpack plugin to write separate values for each export name.
The problem is with CJS we don't statically know what all the export names will be. Since these cases will never be module split, we don't really need to know.
This changes the Flight requires to first look for the specific name we're loading and then if that name doesn't exist in the manifest we fallback to looking for the
"*"name containing the entire module and look for the name in there at runtime.We could probably optimize this a bit if we assume that CJS modules on the server never get built with a name. That way we don't have to do the failed lookup.
Additionally, since we've recently merged filepath + name into a single string instead of two values, we now have to split those back out by parsing the string. This is especially unfortunate for server references since those should really not reveal what they are but be a hash or something. The solution might just be to split them back out into two separate fields again.
cc @shuding