@theguild/federation-composition/esm/supergraph/validation/rules/link-import-name-mismatch-rule.js

Open Source Composition library for Apollo Federation

import { GraphQLError } from 'graphql';
import { andList } from '../../../utils/format.js';
export function LinkImportNameMismatchRule(context) {
    const namesToSubgraphs = new Map();
    const namesToCheck = ['@cost', '@listSize'];
    for (const [subgraphId, subgraphState] of context.subgraphStates) {
        for (const imp of subgraphState.federation.imports) {
            if (!namesToCheck.includes(imp.name)) {
                continue;
            }
            let existing = namesToSubgraphs.get(imp.name);
            if (!existing) {
                namesToSubgraphs.set(imp.name, new Map());
                existing = namesToSubgraphs.get(imp.name);
            }
            const name = imp.alias ?? imp.name;
            let existingName = existing.get(name);
            if (!Array.isArray(existingName)) {
                existing.set(name, []);
                existingName = existing.get(name);
            }
            existingName.push(subgraphId);
        }
    }
    for (const [originalName, aliases] of namesToSubgraphs) {
        if (aliases.size <= 1) {
            continue;
        }
        context.reportError(new GraphQLError(`The import name "${originalName}" is imported with mismatched name between subgraphs: it is imported as ` +
            andList(Array.from(aliases).map(([name, subgraphIds]) => ` "${name}" in subgraph${subgraphIds.length > 1 ? 's' : ''} ${andList(subgraphIds.map(context.graphIdToName), false, '"')}`)), {
            extensions: {
                code: 'LINK_IMPORT_NAME_MISMATCH',
            },
        }));
    }
}