3.1.0-pre.0 bundle size regression with rollup

I know this is prerelease but I just want to give some feedback. This is the same as a comment I made in https://github.com/apollographql/apollo-client/commit/faa64b303447e0d5c745ec27cdd2480338c3763a#r40855898 but I created an issue for more visibility. I tried out 3.1.0.pre.0 and we are seeing a bundle size regression in our rollup bundle. Here is a snippet from dist/core/index.js before and after

export { ApolloClient, } from './ApolloClient';
export { ObservableQuery, } from './ObservableQuery';
export { NetworkStatus } from './networkStatus';
export * from './types';
export { isApolloError, ApolloError } from '../errors';

import '../utilities/graphql/directives.js';
import '../utilities/graphql/fragments.js';
export { isReference, makeReference } from '../utilities/graphql/storeUtils.js';
import '../utilities/graphql/getFromAST.js';
import '../utilities/graphql/transform.js';
export { default as Observable } from 'zen-observable';
import '../utilities/common/mergeDeep.js';
import '../utilities/common/cloneDeep.js';
import '../utilities/common/maybeDeepFreeze.js';

I don’t think rollup is able to treeshake the imports with no specifiers. Please let me know if you need any more info if there are any workarounds.

[benjamn]

@henryqdineen This is great feedback, and really validates the decision to publish -pre.0 before 3.1.0!

I was uneasy with those specifier-less imports too, and couldn’t find a combination of Rollup options to prevent them. I think they have something to do with import hoisting, which is supposedly disabled when preserveModules: true is set (which we do), but apparently not? Ironically, Rollup seems to be creating a problem that it can’t solve (tree-shake) later.

In any case, I am planning to replace resolveESMImportsAndFileExtensions with a step that simply resolves all existing module identifiers, without injecting any new imports or exports.

[henryqdineen]

@benjamn I just tried it out by adding "sideEffects": false to node_modules/graphql-tag/package.json and that did the trick! Are there plans to add that flag to that project? The other solution would work also but seems like a breaking change since we are removing named exports. Thanks as usual!