fragment not deduplicated by client preset

[saihaj]

Hey 👋 I have also encountered this issue, and it's a bit of a potential blocker so I'm hopeful we can resolve it. I've created a minimal repro here: https://codesandbox.io/s/focused-silence-flkogf

It is a very minimal repro but I think shows the essence of the issue. If you run npm run start, the GraphQL query is printed showing two instances of the example SharedComponentFragment fragments I included. This is essentially how my query looks when seeing the error at the network level There can only be one fragment named 'X', so hopefully serves as a suitable reproduction — let me know if not though!

Originally posted by @lrholmes in #8617 (reply in thread)

[lrholmes]

Thanks for creating this issue for us! I'm curious to ask if you have any pointers for how someone could start looking into diagnosing this issue? I've no experience contributing to this repo but this issue is becoming a bit of a blocker for me so am open to helping if I can 🙏

[saihaj]

Hey @lrholmes I started with a repro from the codesanbox to this #8671 I don't think we have a easy way to mock this.

But to fix the issue we just need to make the default to be true here

graphql-code-generator/packages/presets/client/src/index.ts

Line 94 in 224a536

dedupeFragments: options.config.dedupeFragments,

[lrholmes]

Ah amazing, sorry I missed your PR! Thanks for the pointer to this line of code, I noticed that we're currently able to override that at the codegen config level:

    'src/graphql/': {
      documents: ['src/**/*.tsx', '!src/graphql'],
      preset: 'client',
      plugins: [],
      presetConfig: {
        fragmentMasking: { unmaskFunctionName: 'getFragmentData' }
      },
      config: {
        dedupeFragments: true, // <- added this and it works 🎉
      }
    },

Curious if this is could be helped by documentation, as looking at: https://the-guild.dev/graphql/codegen/plugins/presets/preset-client#config-api it wasn't clear to me we had the option of applying these additional config overrides.

[beerose]

Fixed in #8971