Data is undefined on cold cache start

[dilame]

My setup

const graphqlDefaultOptions: DefaultOptions = {
  watchQuery: {
    fetchPolicy: 'cache-and-network'
  }
};

Intended outcome:

I don't want to recieve undefined data. It breaks the whole application and violates your type definitions.
Your types declares that data will always be defined
https://github.com/apollographql/apollo-client/blob/master/src/core/types.ts#L23
so i cant even check the data without @ts-ignore.
It's a pain to check it everywhere

Actual outcome:

I recieve undefined data and a lot of errors in console like ERROR TypeError: Cannot read property 'account' of undefined

How to reproduce the issue:

Just set fetchPolicy: 'cache-and-network' and query smth.

Versions

  System:
    OS: macOS 10.15.2
  Binaries:
    Node: 13.6.0 - /usr/local/bin/node
    Yarn: 1.12.3 - /usr/local/bin/yarn
    npm: 6.13.4 - /usr/local/bin/npm
  Browsers:
    Chrome: 80.0.3987.87
    Firefox: 65.0
    Safari: 13.0.4
  npmPackages:
    apollo-angular: ^1.8.0 => 1.8.0 
    apollo-angular-link-http: ^1.9.0 => 1.9.0 
    apollo-cache-inmemory: ^1.6.0 => 1.6.5 
    apollo-cache-persist: ^0.1.1 => 0.1.1 
    apollo-client: ^2.6.0 => 2.6.8 
    apollo-link: ^1.2.11 => 1.2.13 
    apollo-link-http: ^1.5.16 => 1.5.16 
  npmGlobalPackages:
    apollo: 2.16.1

[benjamn]

@dilame Just to be sure I'm understanding, are you calling client.query (which returns a single Promise), as opposed to using client.watchQuery or useQuery or something that can receive multiple results? If so, then this is definitely a bug.

[dilame]

I'm using client.watchQuery, because cache-and-network works only with it.

[dilame]

I'm sorry, i will use this issue for another one bug report because i have the same setup, dont want to duplicate it.

I've found one more bug.

Even if i subscribe to watchQuery second time (cache is hot at this moment) i have 2 emits, first with loading: true, second is false

But actually there is NO REQUESTS. I can tell it because i look at Network tab of my developer console. So, first, why i have 2 emits even if data is presented in cache? Second - why it shows me loading state when actually it's not?

[bwhitty]

@dilame @benjamn I believe this is the exact same thing as #5947 (just adding another data point to connect dots) which as a reproduction codesandbox

[hwillson]

data being undefined on a cold cache start is intentional (e.g. apollographql/react-apollo#3388 helps explains some of the reasoning for this). Thanks!