@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 visitedGraphs = new Set();
                const [graph, fieldStateInGraph] = graphsWithOverride[i];
                let overrideValue = context.graphNameToId(fieldStateInGraph.override);
                while (overrideValue) {
                    if (visitedGraphs.has(overrideValue)) {
                        context.reportError(new GraphQLError(`Field "${objectTypeState.name}.${fieldState.name}" on subgraph "${context.graphIdToName(graph)}" is also marked with directive @override in subgraph "${context.graphIdToName(overrideValue)}". Only one @override directive is allowed per field.`, {
                            extensions: {
                                code: "OVERRIDE_SOURCE_HAS_OVERRIDE",
                            },
                        }));
                        break;
                    }
                    visitedGraphs.add(overrideValue);
                    const graphFromOverride = overrideValue
                        ? fieldState.byGraph.get(overrideValue)
                        : null;
                    if (!graphFromOverride) {
                        break;
                    }
                    if (!graphFromOverride.override) {
                        break;
                    }
                    overrideValue = context.graphNameToId(graphFromOverride.override);
                }
            }
        },
    };
}
function onlyWithOverride(entry) {
    return entry[1].override !== null;
}