Mark all generated package.json files as "sideEffects": false.

[benjamn]

Should fix #8168 and #5686.

The only side-effectful file we previously advertised was the fixPolyfills.native.js module within @apollo/client/cache, but that file should be used only in React Native, whose Metro bundler does not perform tree-shaking or dead code elimination, which means we never really needed to defend that file from tree-shaking in the first place. In other words, I believe we can get away with putting "sideEffects": false in all of our package.json files, for simplicity (as correctly conjectured by @nwalters512 in #8168).

Background explanation of the "sideEffects": false convention: https://webpack.js.org/guides/tree-shaking/#mark-the-file-as-side-effect-free

[benjamn]

@hwillson @brainkim I think this PR is safe for v3.3.x, but I will cut a v3.4.0-beta.x release first, so we/folks can verify the benefits before we release v3.3.18.

[hwillson]

👍 thanks @benjamn!

[phbou72]

Hi! I'm not sure if this is normal or what in our setup is broken but I'm getting this error when building with Webpack when using that patch :

[client (latest)] Compiling
[error]

[client (latest)] Compile failed with errors
Error: webpack has removed these modules:
    "./node_modules/@apollo/client/cache/index.js",
    "./node_modules/@apollo/client/cache/inmemory/fixPolyfills.js",
    "./node_modules/@apollo/client/index.js"

• If a module is necessary for production, preserve it by adding it to package.json#sideEffects (for more information, see https://github.com/webpack/webpack/tree/master/examples/side-effects)
• If a module can be safely removed, add it to FailOnUnexpectedModuleShakingPlugin's 'exclude' list
    at SOURCE_PATH...

I tried adding the modules to the sideEffects field but no luck!

[nwalters512]

What is FailOnUnexpectedModuleShakingPlugin? I can't find info or source code for that online. Is that a custom in-house plugin you're using? Did you try the suggestion to add the files to the plugin's exclude list?

[brainkim]

@phbou72 As far as I can tell, that is a custom Shopify Webpack plugin? Can you provide more information?

[phbou72]

Thanks for giving feedback so fast guys. I've clarified the situation with the guys at Shopify and yeah like you said it was a plugin causing this. So it's all resolved now! Thanks!