Add specific language to context docs that reference resolvers are necessary for contextual fields #3102
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…cessary for contextual fields
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Thanks for the addition @clenfest . I pushed some copyedits and have some inline clarifying questions.
Finally, it seems like this is a prerequisite and should be mentioned earlier, for example in a Note at the top of the relevant section(s). (E.g.:
Note: Fields that are used with the context directives must be resolvable via a reference resolver. [Learn more](#link-to-section).
Does this apply to just Referencing fields across subgraphs or to all sections on the page?
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| Fields that are used with the context directives must be resolvable via a [reference resolver](/federation/entities/#2-define-a-reference-resolver). Query plans that fetch contextual fields are based on the entity where the `@context` directive is set. Therefore, all subgraphs that resolve that entity must support looking up their fields based on the entity's `@keys` fields. | ||
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| Take the [previous example](#referencing-fields-across-subgraphs). Suppose the first subgraph has a single query to retrieve the logged in user: |
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Added this anchor, as I assumed that's the example we're talking about. Could you please confirm @clenfest ?
| ```typescript title="❌ Incorrect example" disableCopy showLineNumbers=false | ||
| Query: { | ||
| me: () => ({ | ||
| id: 1, userCurrency: { id: 431, currencyCode: 'USD'} |
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Should this be isoCode?
| id: 1, userCurrency: { id: 431, currencyCode: 'USD'} | |
| id: 1, userCurrency: { id: 431, isoCode: 'USD'} |
| } | ||
| ``` | ||
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| This is because the fetch set to subgraph 1 to retrieve the `isoCode` would be done on the entity. Therefore a section to resolve a User by keys would need to be added: |
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This sentence confuses me. Does it mean something like this:
| This is because the fetch set to subgraph 1 to retrieve the `isoCode` would be done on the entity. Therefore a section to resolve a User by keys would need to be added: | |
| It's an inadequate resolver because retrieving the `isoCode` relies on the retrieving the `User` entity itself. Therefore, your resolvers file must include a reference resolver for the `User` entity: |
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I'm also a bit confused by the examples--the incorrect example shows just a resolver for the me query, while the addition below is a reference resolver for User. Would that me query resolver work as written with just the addition? Or does it have to be updated as well?
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