@theguild/federation-composition/esm/supergraph/validation/rules/override-source-has-override.js

Open Source Composition library for Apollo Federation

import { GraphQLError } from 'graphql';
export function OverrideSourceHasOverrideRule(context) {
    return {
        ObjectTypeField(objectTypeState, fieldState) {
            if (fieldState.override === null) {
                return;
            }
            const graphsWithOverride = Array.from(fieldState.byGraph).filter(onlyWithOverride);
            if (graphsWithOverride.length === 1) {
                return;
            }
            for (let i = 0; i < graphsWithOverride.length; i++) {
                const [graph, fieldStateInGraph] = graphsWithOverride[i];
                const overrideValue = fieldStateInGraph.override.toUpperCase();
                const graphFromOverride = fieldState.byGraph.get(overrideValue);
                const anotherGraphId = graphFromOverride && graphFromOverride.override !== null
                    ? overrideValue
                    : graphsWithOverride[i + 1]
                        ? graphsWithOverride[i + 1][0]
                        : graphsWithOverride[0][0];
                context.reportError(new GraphQLError(`Field "${objectTypeState.name}.${fieldState.name}" on subgraph "${context.graphIdToName(graph)}" is also marked with directive @override in subgraph "${context.graphIdToName(anotherGraphId)}". Only one @override directive is allowed per field.`, {
                    extensions: {
                        code: 'OVERRIDE_SOURCE_HAS_OVERRIDE',
                    },
                }));
            }
        },
    };
}
function onlyWithOverride(entry) {
    return entry[1].override !== null;
}