Apollo Client 3.1.0

Bug Fixes

Rework interdependencies between @apollo/client/* entry points, so that CommonJS and ESM modules are supported equally well, without any duplication of shared code.
@benjamn in #6656 and #6657
Tolerate !== callback functions (like onCompleted and onError) in useQuery options, since those functions are almost always freshly evaluated each time useQuery is called.
@hwillson and @benjamn in #6588
Respect context.queryDeduplication if provided, and otherwise fall back to client.deduplication (as before).
@igaloly in #6261 and @Kujawadl in #6526
Refactor ObservableQuery#getCurrentResult to reenable immediate delivery of warm cache results. As part of this refactoring, the ApolloCurrentQueryResult type was eliminated in favor of ApolloQueryResult.
@benjamn in #6710
Avoid clobbering defaultOptions with undefined values.
@benjamn in #6715

Apollo Client will no longer modify options.fetchPolicy unless you pass options.nextFetchPolicy to request an explicit change in FetchPolicy after the current request. Although this is technically a breaking change, options.nextFieldPolicy makes it easy to restore the old behavior (by passing cache-first).
@benjamn in #6712, reverting #6353
Errors of the form Invariant Violation: 42 thrown in production can now be looked up much more easily, by consulting the auto-generated @apollo/client/invariantErrorCodes.js file specific to your @apollo/client version.
@benjamn in #6665
Make the client field of the MutationResult type non-optional, since it is always provided.
@glasser in #6617
Allow passing an asynchronous options.renderFunction to getMarkupFromTree.
@richardscarrott in #6576
Ergonomic improvements for merge and keyArgs functions in cache field policies.
@benjamn in #6714

Avoid duplicating graphql/execution/execute dependency in CommonJS bundle for @apollo/client/link/schema, fixing instanceof errors reported in #6621 and #6614.
@benjamn in #6624

Make sure useQuery onCompleted is not fired when skip is true.
@hwillson in #6589
Revert changes to peerDependencies in package.json (#6594), which would have allowed using incompatible future versions of graphql and/or react due to overly-permissive >= version constraints.
@hwillson in #6605