`generateServiceApolloSources` task fails with `Unexpected 'mapTo' definition` when normalized cache compiler plugin added

[sebj]

When the normalized cache compiler plugin is added to our project, the generateServiceApolloSources task fails with the following error:

Execution failed for task ':shared:api:generateServiceApolloSources'.
> A failure occurred while executing com.apollographql.apollo.gradle.internal.GenerateSources
   > e: null: (115, 1): Unexpected 'mapTo' definition. Expecting 'directive @mapTo (builtIn: BuiltIn!, inline: Boolean! = true) on SCALAR'.

The relevant section of our schema extensions file is as follows:

extend schema @link(url: "https://specs.apollo.dev/kotlin_labs/v0.5/", import: ["@mapTo", "@typePolicy"])

extend scalar Date @mapTo(builtIn: String)
extend scalar DateTime @mapTo(builtIn: String)
extend scalar Time @mapTo(builtIn: String)

The exact plugin declaration added is:

@OptIn(ApolloExperimental::class)
plugin("com.apollographql.cache:normalized-cache-apollo-compiler-plugin:1.0.0-alpha.5") {
    argument("com.apollographql.cache.packageName", packageName.get())
}

This can be reproduced using the cache-plugin branch of the following repository, which has a simplified project: https://github.com/sebj/apollo-kotlin-data-builders-issue-2025-08-06/tree/cache-plugin

[martinbonnin]

Thanks for opening this!

The tldr; is that the cache plugin is re-validating the schema after it's been validated once and the imports merged a first time.

Since the imports are merged, they become "regular" definitions instead of imports and that condition fails.

The quick fix is to import the BuiltIn symbol so that no renaming is hapening:

index 45739ca..6742b75 100644
--- a/app/src/main/graphql/extensions.graphqls
+++ b/app/src/main/graphql/extensions.graphqls
@@ -1,3 +1,3 @@
-extend schema @link(url: "https://specs.apollo.dev/kotlin_labs/v0.5/", import: ["@mapTo"])
+extend schema @link(url: "https://specs.apollo.dev/kotlin_labs/v0.5/", import: ["@mapTo", "BuiltIn"])

The correct fix is probably GraphQL namespacing but I'm not 100% clear about how that would work yet...

[sebj]

Thanks very much, your quick fix works for us!

[martinbonnin]

Thanks for the confirmation. I'll keep this open as a reminder that we need to improve the ergonomics there.