agentic-dev/packages/core-eslint/rules/no-direct-socket-io.js

// packages/core-eslint/rules/no-direct-socket-io.js
const ALLOWED = [
  /\/packages\/core-realtime\/src\//,
  /\/apps\/[^/]+\/server\.ts$/,
  /\/apps\/[^/]+\/src\/.*\.test\.ts$/,
];

export default {
  meta: {
    type: "problem",
    docs: {
      description:
        "Block direct socket.io imports outside core-realtime + app servers",
    },
    messages: {
      noDirectSocketIO:
        'Import from "@repo/core-realtime" instead of "socket.io". Direct imports allowed only in packages/core-realtime/src/ and apps/*/server.ts.',
      noDirectSocketIOClient:
        'Use the realtime helpers from "@repo/core-realtime" / "@repo/core-testing/instrumentation" instead of "socket.io-client".',
    },
    schema: [],
  },
  create(context) {
    const filename = context.filename ?? context.getFilename();
    const allowed = ALLOWED.some((re) => re.test(filename));
    if (allowed) return {};

    return {
      ImportDeclaration(node) {
        const source = node.source.value;
        if (source === "socket.io") {
          context.report({ node, messageId: "noDirectSocketIO" });
        } else if (source === "socket.io-client") {
          context.report({ node, messageId: "noDirectSocketIOClient" });
        }
      },
    };
  },
};