rea/tests/acceptance/applications/exportedFunctionBindingsCli.test.ts

import { execFile } from "node:child_process";
import { createHash } from "node:crypto";
import { mkdir, writeFile } from "node:fs/promises";
import { createRequire } from "node:module";
import { join, resolve } from "node:path";
import { promisify } from "node:util";

import { Client } from "@modelcontextprotocol/client";
import { StdioClientTransport } from "@modelcontextprotocol/client/stdio";
import { afterAll, describe, expect, it } from "vitest";
import { z } from "zod";

import { closeVerifierResources } from "../../../scripts/lib/verifier-cleanup.mjs";
import { javascriptApplicationAnalysisResultSchema } from "../../../src/domain/javascript/javascriptApplicationAnalysis.js";
import { javaScriptExportShapeComparisonResultSchema } from "../../../src/domain/javascript/javascriptExportShapeComparisonSchemas.js";
import { createTestTempDirectory } from "../../fixtures/temporaryDirectory.js";
import {
  startCompiledCliSession,
  type CompiledCliSession,
} from "../../support/cli/compiledCliSession.js";

const execute = promisify(execFile);
const requireFixture = createRequire(import.meta.url);
const comparisonEnvelope = z.object({
  normalized_result: javaScriptExportShapeComparisonResultSchema,
});
const applicationEnvelope = z.object({
  normalized_result: javascriptApplicationAnalysisResultSchema,
});
let cliSession: CompiledCliSession | undefined;

// Source semantics use one real stdio MCP session. Cases that also check the
// compiled CLI adapter share one warm process: it loads the production command
// runtime once and serves the same JSON commands as scripts/rea.mjs.
let mcpConnection:
  | {
      readonly client: Client;
      readonly transport: StdioClientTransport;
      readonly ready: Promise<void>;
    }
  | undefined;

afterAll(async () => {
  if (mcpConnection !== undefined) {
    try {
      await mcpConnection.ready;
    } catch {
      // Keep the failed connection owned until both resources are closed below.
    }
  }
  await closeVerifierResources([
    async () => {
      await mcpConnection?.client.close();
    },
    async () => {
      await mcpConnection?.transport.close();
    },
    async () => {
      await cliSession?.close();
    },
  ]);
});

describe("exported function binding resolution through stdio MCP and CLI", () => {
  it.each([
    {
      name: "a function declaration exported by a specifier",
      exportName: "default",
      source: (count: number) =>
        `function current() { return { count: 0 }; }
         current = () => ({ count: ${String(count)} });
         export { current as default };`,
    },
    {
      name: "a directly exported function declaration",
      exportName: "current",
      source: (count: number) =>
        `export function current() { return { count: 0 }; }
         current = () => ({ count: ${String(count)} });`,
    },
    {
      name: "a named default function declaration",
      exportName: "default",
      source: (count: number) =>
        `export default function current() { return { count: 0 }; }
         current = () => ({ count: ${String(count)} });`,
    },
    {
      name: "a directly exported arrow binding",
      exportName: "current",
      source: (count: number) =>
        `export let current = () => ({ count: 0 });
         current = () => ({ count: ${String(count)} });`,
    },
    {
      name: "an arrow binding exported by a specifier",
      exportName: "default",
      source: (count: number) =>
        `let current = () => ({ count: 0 });
         current = () => ({ count: ${String(count)} });
         export { current as default };`,
    },
    {
      name: "a reassigned alias",
      exportName: "default",
      source: (count: number) =>
        `const original = () => ({ count: 0 });
         let current = original;
         current = () => ({ count: ${String(count)} });
         export { current as default };`,
    },
    {
      name: "a conditional function reassignment",
      exportName: "current",
      source: (count: number) =>
        `export function current() { return { count: 0 }; }
         if (true) current = () => ({ count: ${String(count)} });`,
    },
  ])(
    "keeps $name uncertain after reassignment",
    async ({ source, exportName }) => {
      const fixture = await analyzeVersions(source, exportName);
      await expectRuntimeExports(fixture, (count) => ({ count }));
      const result = await compareThroughMcp(fixture.input);
      expectUncertainComparison(result);
      for (const evidence of [fixture.input.left, fixture.input.right]) {
        const { normalized_result: analysis } = z
          .object({
            normalized_result: javascriptApplicationAnalysisResultSchema,
          })
          .parse(evidence);
        expect(
          analysis.graph.nodes
            .flatMap(({ observations }) => observations)
            .filter(
              ({ properties }) =>
                properties.semantic_role === "export-return-shapes" &&
                properties.exported_name === exportName,
            ),
        ).toEqual([]);
      }
    },
  );

  it("does not associate a private function name with a numeric export through stdio MCP", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `const hidden = function current() { return { count: 0 }; };
       const current = ${String(count)};
       export { current as default };`,
      "default",
    );
    await expectRuntimeExports(fixture, (count) => count);
    const comparison = await compareThroughMcp(fixture.input);
    expectUncertainComparison(comparison);
  });

  it("does not treat rebinding the CommonJS exports alias as a default export", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `exports = function parse() { return { kind: "result", count: ${String(count)} }; };`,
      "default",
      "app.cjs",
    );

    // This is a test-owned fixture, so Node's actual CommonJS loader is the
    // oracle for what the application exports.
    expect(requireFixture(fixture.leftPath)).toEqual({});
    expect(requireFixture(fixture.rightPath)).toEqual({});

    const mcp = await compareThroughMcp(fixture.input);
    await expectCliAnalysisParity(fixture);
    expect(mcp).toMatchObject({
      left: { status: "missing" },
      right: { status: "missing" },
      summary: { added: 0, removed: 0, changed: 0 },
    });
    expect(await compareThroughCli(fixture)).toEqual(mcp);
  });

  it.each([
    ["the CommonJS exports alias", "exports"],
    ["an ordinary object property", "holder.value"],
  ])(
    "resolves exported callable values through = chains ending at %s",
    async (_, target) => {
      const fixture = await analyzeVersions(
        (count) =>
          `const holder = {};\nfunction parse() { return { kind: "result", count: ${String(count)} }; }\nmodule.exports = ${target} = parse;`,
        "default",
        "app.cjs",
      );
      expect(requireFixture(fixture.leftPath)()).toEqual({
        kind: "result",
        count: 1,
      });
      expect(requireFixture(fixture.rightPath)()).toEqual({
        kind: "result",
        count: 2,
      });
      for (const evidence of [fixture.input.left, fixture.input.right])
        expectExportedCallableBinding(evidence, "parse");
      const comparison = await compareThroughMcp(fixture.input);
      expectCountChange(comparison);
      if (target === "exports") {
        await expectCliAnalysisParity(fixture);
        expect(await compareThroughCli(fixture)).toEqual(comparison);
      }
    },
  );
});

describe("CommonJS receiver lifetimes through stdio MCP and CLI", () => {
  it.each([
    "module.exports = {}; exports.parse = VALUE;",
    "exports = {}; exports.parse = VALUE;",
    "exports.parse = VALUE; module.exports = {};",
    "module.exports.parse = VALUE; module.exports = {};",
    "module.exports = {}; exports = module.exports; module.exports = {}; exports.parse = VALUE;",
    'module.exports = {}; exports.parse = "enabled";',
    'module.exports = {}; Reflect.set(module, "other", exports); exports.parse = VALUE;',
    "module.exports = {}; let wrapper = module; wrapper = {}; Object.assign(wrapper, { exports }); exports.parse = VALUE;",
  ])("excludes detached public export receivers: %s", async (source) => {
    const fixture = await analyzeVersions(
      (count) =>
        source.replace(
          "VALUE",
          `() => ({ kind: "result", count: ${String(count)} })`,
        ),
      "parse",
      "app.cjs",
    );
    for (const path of [fixture.leftPath, fixture.rightPath]) {
      const value = requireFixture(path);
      expect(Object.hasOwn(value, "parse")).toBe(false);
      expect(value.parse).toBeUndefined();
    }
    for (const evidence of [fixture.input.left, fixture.input.right]) {
      const { graph } = applicationEnvelope.parse(evidence).normalized_result;
      expect(
        graph.nodes
          .flatMap(({ observations }) => observations)
          .filter(
            ({ properties }) =>
              properties.exported_name === "parse" &&
              ["export-binding", "export-return-shapes"].includes(
                String(properties.semantic_role),
              ),
          ),
      ).toEqual([]);
    }
    await expectCliAnalysisParity(fixture);
    const comparison = await compareThroughMcp(fixture.input);
    expect(comparison).toMatchObject({
      left: { status: "missing" },
      right: { status: "missing" },
      summary: { added: 0, removed: 0, changed: 0 },
    });
    expect(await compareThroughCli(fixture)).toEqual(comparison);
  });

  it.each([
    "exports.parse = VALUE;",
    "module.exports = {}; module.exports.parse = VALUE;",
    "module.exports = {}; exports = module.exports; exports.parse = VALUE;",
    "exports.parse = VALUE; Object.assign(module.exports, { other: exports });",
  ])("retains connected public export receivers: %s", async (source) => {
    const fixture = await analyzeVersions(
      (count) =>
        source.replace(
          "VALUE",
          `() => ({ kind: "result", count: ${String(count)} })`,
        ),
      "parse",
      "app.cjs",
    );
    for (const [path, count] of [
      [fixture.leftPath, 1],
      [fixture.rightPath, 2],
    ] as const)
      expect(requireFixture(path).parse()).toEqual({ kind: "result", count });
    await expectCliAnalysisParity(fixture);
    const comparison = await compareThroughMcp(fixture.input);
    expectCountChange(comparison);
    expect(await compareThroughCli(fixture)).toEqual(comparison);
  });

  it.each([
    "if (false) module.exports = {}; exports.parse = VALUE;",
    "exports.parse = VALUE; if (false) module.exports = {};",
    "function replace() { module.exports = {}; } exports.parse = VALUE;",
    "function replace() { exports = {}; } exports.parse = VALUE;",
    'const holder = {}; ({ [(module.exports = exports, "x")]: holder.x } = (module.exports = {})); exports.parse = VALUE;',
    'const { [(module.exports = exports, "x")]: value } = (module.exports = {}); exports.parse = VALUE;',
    "const [value = (module.exports = exports)] = (module.exports = []); exports.parse = VALUE;",
    "module.exports = {}; Object.assign(module, { exports }); exports.parse = VALUE;",
    'module.exports = {}; Object.defineProperty(module, "exports", { value: exports }); exports.parse = VALUE;',
    'module.exports = {}; Reflect.set(module, "exports", exports); exports.parse = VALUE;',
    "module.exports = {}; const assign = Object.assign; assign.call(null, module, { exports }); exports.parse = VALUE;",
    "module.exports = {}; const wrapper = module; Object.assign(wrapper, { exports }); exports.parse = VALUE;",
  ])(
    "keeps execution-dependent receiver identity uncertain: %s",
    async (source) => {
      const fixture = await analyzeVersions(
        (count) =>
          source.replace(
            "VALUE",
            `() => ({ kind: "result", count: ${String(count)} })`,
          ),
        "parse",
        "app.cjs",
      );
      for (const [path, count] of [
        [fixture.leftPath, 1],
        [fixture.rightPath, 2],
      ] as const)
        expect(requireFixture(path).parse()).toEqual({ kind: "result", count });
      for (const evidence of [fixture.input.left, fixture.input.right])
        expectUnresolvedExportBinding(evidence, "parse");
      await expectCliAnalysisParity(fixture);
      const comparison = await compareThroughMcp(fixture.input);
      expectUncertainComparison(comparison);
      expect(await compareThroughCli(fixture)).toEqual(comparison);
    },
  );
});

describe("CommonJS assignment-chain receiver identity through stdio MCP", () => {
  it("does not export a named write whose captured module.exports receiver is replaced", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `const VERSION = ${String(count)};\nmodule.exports.parse = (module.exports = () => ({ count: VERSION }));`,
      "parse",
      "app.cjs",
    );
    for (const path of [fixture.leftPath, fixture.rightPath]) {
      const value = requireFixture(path);
      expect(typeof value).toBe("function");
      expect(Reflect.ownKeys(value)).toEqual(["length", "name"]);
    }
    for (const evidence of [fixture.input.left, fixture.input.right]) {
      const analysis = z
        .object({
          normalized_result: javascriptApplicationAnalysisResultSchema,
        })
        .parse(evidence).normalized_result;
      expect(
        analysis.graph.nodes
          .flatMap(({ observations }) => observations)
          .filter(
            ({ properties }) =>
              properties.semantic_role === "export-binding" &&
              properties.exported_name === "parse",
          ),
      ).toEqual([]);
    }
    const comparison = await compareThroughMcp(fixture.input);
    expect(comparison).toMatchObject({
      left: { status: "missing" },
      right: { status: "missing" },
      summary: { added: 0, removed: 0, changed: 0 },
    });
  });

  it("keeps a named property export when its receiver remains stable through the RHS chain", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `const holder = {};\nfunction parse() { return { kind: "result", count: ${String(count)} }; }\nmodule.exports.parse = holder.value = parse;`,
      "parse",
      "app.cjs",
    );
    for (const path of [fixture.leftPath, fixture.rightPath])
      expect(requireFixture(path).parse()).toEqual({
        kind: "result",
        count: path === fixture.leftPath ? 1 : 2,
      });
    const comparison = await compareThroughMcp(fixture.input);
    expectCountChange(comparison);
  });

  it("keeps receiver identity unresolved when module.exports is reassigned to the same function", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `const VERSION = ${String(count)};\nfunction parse() { return { count: VERSION }; }\nmodule.exports = parse;\nmodule.exports.parse = (module.exports = parse);`,
      "parse",
      "app.cjs",
    );
    for (const path of [fixture.leftPath, fixture.rightPath]) {
      const value = requireFixture(path);
      expect(value.parse).toBe(value);
      expect(value.parse()).toEqual({
        count: path === fixture.leftPath ? 1 : 2,
      });
    }
    for (const evidence of [fixture.input.left, fixture.input.right])
      expectUnresolvedExportBinding(evidence, "parse");
    const comparison = await compareThroughMcp(fixture.input);
    expect(comparison).toMatchObject({
      left: { status: "unavailable" },
      right: { status: "unavailable" },
    });
  });

  it("keeps receiver replacement by an existing function unresolved", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `const VERSION = ${String(count)};\nfunction parse() { return { count: VERSION }; }\nmodule.exports.parse = (module.exports = parse);`,
      "parse",
      "app.cjs",
    );
    for (const path of [fixture.leftPath, fixture.rightPath]) {
      const value = requireFixture(path);
      expect(typeof value).toBe("function");
      expect(value.parse).toBeUndefined();
      expect(value()).toEqual({
        count: path === fixture.leftPath ? 1 : 2,
      });
    }
    for (const evidence of [fixture.input.left, fixture.input.right])
      expectUnresolvedExportBinding(evidence, "parse");
    const comparison = await compareThroughMcp(fixture.input);
    expect(comparison).toMatchObject({
      left: { status: "unavailable" },
      right: { status: "unavailable" },
    });
  });

  it("resolves a nested lexical parse binding in an ordinary module.exports chain", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `function parse() { return { count: VERSION }; }\nfunction configure() { const parse = () => ({ count: 7 }); let local; module.exports = local = parse; }\nconst VERSION = ${String(count)};\nconfigure();`,
      "default",
      "app.cjs",
    );
    for (const path of [fixture.leftPath, fixture.rightPath])
      expect(requireFixture(path)()).toEqual({ count: 7 });
    for (const evidence of [fixture.input.left, fixture.input.right])
      expectExportedCallableBinding(evidence, "parse");
    const comparison = await compareThroughMcp(fixture.input);
    expect(comparison).toMatchObject({
      summary: { added: 0, removed: 0, changed: 0, unknown: 0 },
      changes: [],
    });
  });
});

describe("CommonJS export identity and scope regressions", () => {
  it("does not export a named write through the original exports alias after replacement", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `const VERSION = ${String(count)};\nexports.parse = (module.exports = () => ({ count: VERSION }));`,
      "parse",
      "app.cjs",
    );
    for (const path of [fixture.leftPath, fixture.rightPath]) {
      const value = requireFixture(path);
      expect(typeof value).toBe("function");
      expect(Reflect.ownKeys(value)).toEqual(["length", "name"]);
    }
    const comparison = await compareThroughMcp(fixture.input);
    expect(comparison).toMatchObject({
      left: { status: "missing" },
      right: { status: "missing" },
      summary: { added: 0, removed: 0, changed: 0 },
    });
  });

  it("keeps a dead var shadow of the alias-chain RHS unavailable", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `function parse() { return { count: ${String(count)} }; }\nfunction configure() { if (false) { var parse = () => ({ count: 7 }); } module.exports = exports = parse; }\nconfigure();`,
      "default",
      "app.cjs",
    );
    expect(requireFixture(fixture.leftPath)).toBeUndefined();
    expect(requireFixture(fixture.rightPath)).toBeUndefined();
    const comparison = await compareThroughMcp(fixture.input);
    expectUncertainComparison(comparison);
  });

  it.each(["+=", "||=", "??="] as const)(
    "does not treat module.exports %s as a definite function export",
    async (operator) => {
      const fixture = await analyzeVersions(
        (count) =>
          `module.exports ${operator} (() => ({ kind: "result", count: ${String(count)} }));`,
        "default",
        "app.cjs",
      );
      const left = requireFixture(fixture.leftPath);
      const right = requireFixture(fixture.rightPath);
      if (operator === "+=") {
        expect(typeof left).toBe("string");
        expect(typeof right).toBe("string");
      } else {
        expect(left).toEqual({});
        expect(right).toEqual({});
      }
      const comparison = await compareThroughMcp(fixture.input);
      expectUncertainComparison(comparison);
    },
  );

  it("keeps a parameter-default mutation unknown in a CommonJS return shape", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `const source = { value: 0 }; module.exports = exports = function current(arg = null, set = (arg = source)) { var arg; arg.value = ${String(count)}; return { kind: "result", count: source.value }; };`,
      "default",
      "app.cjs",
    );
    expect(requireFixture(fixture.leftPath)()).toEqual({
      kind: "result",
      count: 1,
    });
    expect(requireFixture(fixture.rightPath)()).toEqual({
      kind: "result",
      count: 2,
    });
    for (const evidence of [fixture.input.left, fixture.input.right]) {
      const analysis = z
        .object({
          normalized_result: javascriptApplicationAnalysisResultSchema,
        })
        .parse(evidence).normalized_result;
      const shapes = analysis.graph.nodes
        .flatMap(({ observations }) => observations)
        .find(
          ({ properties }) =>
            properties.semantic_role === "export-return-shapes" &&
            properties.exported_name === "default",
        )?.properties.static_return_shapes;
      expect(shapes).toEqual([
        expect.objectContaining({
          fields: expect.arrayContaining([
            expect.objectContaining({ path: "/count", state: "unknown" }),
          ]),
        }),
      ]);
    }
    const comparison = await compareThroughMcp(fixture.input);
    expect(comparison).toMatchObject({
      left: { status: "selected" },
      right: { status: "selected" },
      summary: { added: 0, removed: 0, changed: 0 },
      changes: [],
    });
  });
});

describe("stable exported function bindings through stdio MCP", () => {
  it.each([
    {
      name: "an anonymous default",
      source: (count: number) =>
        `export default () => ({ kind: "result", count: ${String(count)} });`,
    },
    {
      name: "a named default declaration",
      source: (count: number) =>
        `export default function current() { return { kind: "result", count: ${String(count)} }; }`,
    },
    {
      name: "a private named default expression",
      source: (count: number) =>
        `export default (function current() { return { kind: "result", count: ${String(count)} }; });`,
    },
    {
      name: "a declaration alias",
      source: (count: number) =>
        `function original() { return { kind: "result", count: ${String(count)} }; }
       const current = original; export { current as default };`,
    },
    {
      name: "an unchanged mutable binding",
      source: (count: number) =>
        `let current = () => ({ kind: "result", count: ${String(count)} }); export { current as default };`,
    },
    {
      name: "a private function reached through its real binding",
      source: (count: number) =>
        `const current = function privateName() { return { kind: "result", count: ${String(count)} }; };
       const privateName = 99; const alias = current; export { alias as default };`,
    },
    {
      name: "a declaration sharing a private display name",
      source: (count: number) =>
        `const hidden = function current() { return { count: 99 }; };
       function current() { return { kind: "result", count: ${String(count)} }; }
       export { current as default };`,
    },
  ])("retains exact comparison for $name", async ({ source }) => {
    const fixture = await analyzeVersions(source, "default");
    expectCountChange(await compareThroughMcp(fixture.input));
  });

  it.each([
    {
      name: "a local callable captured by an identifier default export",
      source: (count: number) =>
        `const run = () => ({ kind: "result", count: ${String(count)} });\nexport default run;`,
      runtimeValue: (count: number) => ({ kind: "result", count }),
      expected: "known",
    },
    {
      name: "the latest callable assigned before the default export",
      source: (count: number) =>
        `let run = () => ({ count: 0 });\nrun = () => ({ kind: "result", count: ${String(count)} });\nexport default run;`,
      runtimeValue: (count: number) => ({ kind: "result", count }),
      expected: "known",
    },
    {
      name: "a callable assigned only after the default export capture",
      source: (count: number) =>
        `var run;\nexport default run;\nrun = () => ({ kind: "result", count: ${String(count)} });`,
      runtimeValue: () => undefined,
      expected: "unknown",
    },
    {
      name: "a reassignment after the default export capture",
      source: (count: number) =>
        `let run = () => ({ kind: "result", count: ${String(count)} });\nexport default run;\nrun = () => ({ count: 99 });`,
      runtimeValue: (count: number) => ({ kind: "result", count }),
      expected: "known",
    },
  ] as const)(
    "uses the value at $name",
    async ({ source, runtimeValue, expected }) => {
      const fixture = await analyzeVersions(source, "default");
      await expectRuntimeExports(fixture, runtimeValue);
      const mcp = await compareThroughMcp(fixture.input);
      const cli = await compareThroughCli(fixture);
      expect(cli).toEqual(mcp);
      if (expected === "known") expectCountChange(mcp);
      else expectUncertainComparison(mcp);
    },
  );
});

describe("export bindings with loop and assignment-only writes", () => {
  it.each([
    ["a skipped branch", "if (false)"],
    ["a zero-iteration loop", "for (; false;)"],
    ["an unselected switch case", "switch (0) { case 1:"],
    ["an interrupted try block", "try { throw 1;"],
  ])("does not infer a callable initialized in %s", async (_, prefix) => {
    const fixture = await analyzeVersions((count) => {
      const initializer = `var current = () => ({ count: ${String(count)} });`;
      const statement = prefix.startsWith("try")
        ? `${prefix} ${initializer} } catch {}`
        : prefix.startsWith("switch")
          ? `${prefix} ${initializer} }`
          : `${prefix} { ${initializer} }`;
      return `${statement} export { current as default };`;
    }, "default");
    await expectRuntimeExports(fixture, () => undefined);
    expectUncertainComparison(await compareThroughMcp(fixture.input));
  });

  it("retains a var initializer in an unconditional nested block", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `{ var current = () => ({ kind: "result", count: ${String(count)} }); }
         export { current as default };`,
      "default",
    );
    await expectRuntimeExports(fixture, (count) => ({ kind: "result", count }));
    expectCountChange(await compareThroughMcp(fixture.input));
  });

  it.each([
    {
      name: "a for-of var declaration",
      loop: (count: number) =>
        `for (var current of [() => ({ count: ${String(count)} })]) {}`,
    },
    {
      name: "a destructured for-of var declaration",
      loop: (count: number) =>
        `for (var { value: current } of [{ value: () => ({ count: ${String(count)} }) }]) {}`,
    },
  ])("keeps $name uncertain", async ({ loop }) => {
    const fixture = await analyzeVersions(
      (count) =>
        `function current() { return { count: 0 }; }
         ${loop(count)}
         module.exports = current;`,
      "default",
      "app.cjs",
    );
    await expectRuntimeExports(fixture, (count) => ({ count }));
    expectUncertainComparison(await compareThroughMcp(fixture.input));
  });

  it("does not associate a for-in key with the overwritten function", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `function current() { return { count: 0 }; }
         for (var current in { ${String(count)}: true }) {}
         module.exports = current;`,
      "default",
      "app.cjs",
    );
    await expectRuntimeExports(fixture, String);
    expectUncertainComparison(await compareThroughMcp(fixture.input));
  });

  it("preserves an outer export shadowed by a lexical loop declaration", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `export function current() { return { kind: "result", count: ${String(count)} }; }
         for (let current of [() => ({ count: 0 })]) { current = null; }`,
      "current",
    );
    await expectRuntimeExports(fixture, (count) => ({ kind: "result", count }));
    expectCountChange(await compareThroughMcp(fixture.input));
  });

  it.each([
    {
      name: "a parameter",
      source: (count: number) =>
        `function install(current) {
           if (false) current = () => ({ count: 0 });
           module.exports = current;
         }
         install(${String(count)});`,
    },
    {
      name: "a catch binding",
      source: (count: number) =>
        `try { throw ${String(count)}; } catch (current) {
           if (false) current = () => ({ count: 0 });
           module.exports = current;
         }`,
    },
    {
      name: "a parameter redeclared with var",
      source: (count: number) =>
        `function install(current) {
           if (false) { var current = () => ({ count: 0 }); }
           module.exports = current;
         }
         install(${String(count)});`,
    },
  ])("does not infer $name from its only assignment", async ({ source }) => {
    const fixture = await analyzeVersions(source, "default", "app.cjs");
    await expectRuntimeExports(fixture, (count) => count);
    const comparison = await compareThroughMcp(fixture.input);
    expectUncertainComparison(comparison);
  });
});

describe("export binding lexical scope and declaration order", () => {
  it.each([
    {
      name: "a write before a hoisted function declaration",
      source: (count: number) =>
        `current = () => ({ count: ${String(count)} });
         export function current() { return { count: 0 }; }`,
    },
    {
      name: "a nested write collected before its outer declaration",
      source: (count: number) =>
        `function replace() { current = () => ({ count: ${String(count)} }); }
         export function current() { return { count: 0 }; }
         replace();`,
    },
  ])("keeps $name uncertain", async ({ source }) => {
    const fixture = await analyzeVersions(source, "current");
    await expectRuntimeExports(fixture, (count) => ({ count }));
    expectUncertainComparison(await compareThroughMcp(fixture.input));
  });

  it("does not let a later local declaration contaminate the exported outer binding", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `export function current() { return { kind: "result", count: ${String(count)} }; }
       function isolated() {
         current = () => ({ count: 9 });
         function current() { return { count: 0 }; }
       }
       isolated();`,
      "current",
    );
    await expectRuntimeExports(fixture, (count) => ({ kind: "result", count }));
    expectCountChange(await compareThroughMcp(fixture.input));
  });

  it("does not associate a nested CommonJS numeric export with an outer function", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `function current() { return { count: 0 }; }
       function install() { const current = ${String(count)}; module.exports = current; }
       install();`,
      "default",
      "app.cjs",
    );
    await expectRuntimeExports(fixture, (count) => count);
    const comparison = await compareThroughMcp(fixture.input);
    expectUncertainComparison(comparison);
  });

  it.each([
    {
      name: "a nested function-local alias",
      source: (count: number) =>
        `function current() { return { kind: "result", count: 0 }; }
         function install() {
           const actual = () => ({ kind: "result", count: ${String(count)} });
           const current = actual; module.exports = current;
         }
         install();`,
    },
    {
      name: "a block-local function",
      source: (count: number) =>
        `const current = 0;
         { const current = () => ({ kind: "result", count: ${String(count)} });
           module.exports = current; }`,
    },
  ])("compares $name through its real CommonJS binding", async ({ source }) => {
    const fixture = await analyzeVersions(source, "default", "app.cjs");
    await expectRuntimeExports(fixture, (count) => ({ kind: "result", count }));
    expectCountChange(await compareThroughMcp(fixture.input));
  });
});

describe("export writes in function evaluation contexts", () => {
  it.each([
    { body: "var arg; arg.value = COUNT;", uncertain: true },
    { body: "var arg = arg; arg.value = COUNT;", uncertain: true },
    { body: "arg.value = COUNT; var arg;", uncertain: true },
    { body: "arg.value = COUNT; var arg = {};", uncertain: true },
    { body: "var arg = {}; arg.value = COUNT;", uncertain: false },
    { body: "var arg; arg = {}; arg.value = COUNT;", uncertain: false },
    { body: "function arg() {} arg.value = COUNT;", uncertain: false },
  ])("retains parameter-copy timing for $body", async ({ body, uncertain }) => {
    const fixture = await analyzeVersions(
      (count) =>
        `const source = { value: 0 };
         export function current(arg = null, set = (arg = source)) {
           ${body.replace("COUNT", String(count))}
           return { kind: "result", count: source.value };
         }`,
      "current",
    );
    await expectRuntimeExports(fixture, (count) => ({
      kind: "result",
      count: uncertain ? count : 0,
    }));
    for (const evidence of [fixture.input.left, fixture.input.right]) {
      const { normalized_result: analysis } = z
        .object({
          normalized_result: javascriptApplicationAnalysisResultSchema,
        })
        .parse(evidence);
      const observations = analysis.graph.nodes.flatMap(
        ({ observations }) => observations,
      );
      expect(observations).toEqual(
        expect.arrayContaining([
          expect.objectContaining({
            properties: expect.objectContaining({
              semantic_role: "export-return-shapes",
              exported_name: "current",
              static_return_shapes: [
                expect.objectContaining({
                  fields: expect.arrayContaining([
                    expect.objectContaining({
                      path: "/count",
                      state: uncertain ? "unknown" : "literal",
                      value: uncertain ? null : 0,
                    }),
                  ]),
                }),
              ],
            }),
          }),
        ]),
      );
    }
  });

  it.each([
    ...["let current;", "var current;", "function current() {}"].map(
      (body) => ({
        name: `a parameter default before ${body}`,
        source: (count: number) =>
          `export function current() { return { count: 0 }; }
         function replace(value = (current = () => ({ count: ${String(count)} }))) {
           ${body}
         }
         replace();`,
      }),
    ),
    {
      name: "a closure invoked from a parameter default",
      source: (count: number) =>
        `export function current() { return { count: 0 }; }
         function replace(value = (() => { current = () => ({ count: ${String(count)} }); })()) {
           let current;
         }
         replace();`,
    },
    {
      name: "a computed destructuring parameter key",
      source: (count: number) =>
        `export function current() { return { count: 0 }; }
         function replace({ [current = () => ({ count: ${String(count)} })]: value }) {
           var current;
         }
         replace({});`,
    },
    {
      name: "an object method's computed key",
      source: (count: number) =>
        `export function current() { return { count: 0 }; }
         const object = { [current = () => ({ count: ${String(count)} })]() { let current; } };`,
    },
    {
      name: "a class method's computed key",
      source: (count: number) =>
        `export function current() { return { count: 0 }; }
         class Example { [current = () => ({ count: ${String(count)} })]() { var current; } }`,
    },
  ])("keeps an outer export write in $name uncertain", async ({ source }) => {
    const fixture = await analyzeVersions(source, "current");
    await expectRuntimeExports(fixture, (count) => ({ count }));
    expectUncertainComparison(await compareThroughMcp(fixture.input));
  });

  it("resolves a CommonJS export in a parameter default outside the function body", async () => {
    const fixture = await analyzeVersions(
      (count) =>
        `function current() { return { kind: "result", count: ${String(count)} }; }
         function install(value = (module.exports = current)) { var current = 9; }
         install();`,
      "default",
      "app.cjs",
    );
    await expectRuntimeExports(fixture, (count) => ({ kind: "result", count }));
    expectCountChange(await compareThroughMcp(fixture.input));
  });
});

it("retains namespace re-export bindings and provenance through stdio MCP and CLI", async () => {
  const root = await createTestTempDirectory("rea-namespace-reexports-");
  const declarations = [
    { clause: "* as ns", name: "ns", imported: "*" },
    {
      clause: '* as "namespace value"',
      name: "namespace value",
      imported: "*",
    },
    { clause: "{ value as forwarded }", name: "forwarded", imported: "value" },
    { clause: "*", name: "*", imported: "*" },
  ];
  const source = declarations
    .map(({ clause }) => `export ${clause} from "./dependency.mjs";`)
    .join("\n");
  const path = join(root, "barrel.mjs");
  await Promise.all([
    writeFile(path, source),
    writeFile(join(root, "dependency.mjs"), "export const value = 42;"),
  ]);
  // Node executes only this test-owned fixture to establish its actual exports.
  for (const name of ["ns", "namespace value"])
    expect(await runtimeExport(path, name)).toEqual({ value: 42 });
  for (const name of ["forwarded", "value"])
    expect(await runtimeExport(path, name)).toBe(42);

  const documents = [
    await analyzeThroughMcp(root),
    await runCli(["analyze-javascript-application", root, "--json"]),
  ];
  const digest = createHash("sha256").update(source).digest("hex");
  for (const document of documents) {
    const { graph } = applicationEnvelope.parse(document).normalized_result;
    const sourceModule = graph.nodes.find(({ observations }) =>
      observations.some(
        ({ properties }) =>
          properties.semantic_role === "source-module" &&
          properties.path === "barrel.mjs",
      ),
    );
    expect(sourceModule?.observations[0]?.properties).toMatchObject({
      export_relationships: 4,
      export_names: ["*", "forwarded", "namespace value", "ns"],
      omitted_export_names: 0,
    });
    for (const [index, { clause, name, imported }] of declarations.entries()) {
      const exported = graph.nodes.find(({ observations }) =>
        observations.some(
          ({ properties }) =>
            properties.semantic_role === "export-binding" &&
            properties.module_path === "barrel.mjs" &&
            properties.exported_name === name,
        ),
      );
      const observation = exported?.observations[0];
      expect(observation?.properties).toMatchObject({
        relationship_kind: "re-export",
        declared_specifier: "./dependency.mjs",
        imported_name: imported,
        local_name: null,
      });
      if (imported === "*" && name !== "*")
        expect(observation?.evidence).toMatchObject({
          artifact: { available: true, sha256: digest },
          location: {
            available: true,
            value: {
              kind: "source-range",
              source: "barrel.mjs",
              start: { line: index + 1, column: 7 },
              end: { line: index + 1, column: 7 + clause.length },
            },
          },
        });
      expect(graph.edges).toContainEqual(
        expect.objectContaining({
          source_node_id: sourceModule?.node_id,
          target_node_id: exported?.node_id,
          relation: "exposes",
          properties: expect.objectContaining({ exported_name: name }),
          evidence: expect.objectContaining({
            artifact: observation?.evidence.artifact,
            location: observation?.evidence.location,
          }),
        }),
      );
      expect(graph.edges).toContainEqual(
        expect.objectContaining({
          source_node_id: exported?.node_id,
          relation: "imports",
          properties: expect.objectContaining({
            module_link_kind: "re-export",
            imported_name: imported,
            exported_name: name,
            resolved_path: "dependency.mjs",
            resolution_status: "resolved",
          }),
        }),
      );
    }
    expect(graph.coverage).toMatchObject({
      status: "complete",
      omitted_count: 0,
      truncated: false,
    });
  }
});

it("excludes erased namespace type exports through stdio MCP and CLI", async () => {
  const root = await createTestTempDirectory("rea-namespace-type-exports-");
  const path = join(root, "barrel.mts");
  await Promise.all([
    writeFile(
      path,
      'export type * as Types from "./types.mjs";\nexport * as Values from "./values.mjs";',
    ),
    writeFile(
      join(root, "types.mjs"),
      'throw new Error("Type-only dependency must not execute");',
    ),
    writeFile(join(root, "values.mjs"), "export const value = 42;"),
  ]);
  // Node strips the type-only declaration without loading its throwing target.
  expect(await runtimeExport(path, "Types")).toBeUndefined();
  expect(await runtimeExport(path, "Values")).toEqual({ value: 42 });

  const documents = [
    await analyzeThroughMcp(root),
    await runCli(["analyze-javascript-application", root, "--json"]),
  ];
  for (const document of documents) {
    const { graph } = applicationEnvelope.parse(document).normalized_result;
    const observations = graph.nodes.flatMap(
      ({ observations }) => observations,
    );
    expect(
      observations.find(
        ({ properties }) =>
          properties.semantic_role === "source-module" &&
          properties.path === "barrel.mts",
      )?.properties,
    ).toMatchObject({
      export_relationships: 1,
      export_names: ["Values"],
      omitted_export_names: 0,
    });
    expect(
      observations.filter(
        ({ properties }) =>
          properties.semantic_role === "export-binding" &&
          properties.module_path === "barrel.mts" &&
          properties.exported_name === "Types",
      ),
    ).toEqual([]);
    expect(
      graph.edges.filter(
        ({ properties }) => properties.exported_name === "Types",
      ),
    ).toEqual([]);
    expect(graph.coverage).toMatchObject({
      status: "complete",
      omitted_count: 0,
      truncated: false,
    });
  }
});

const expectRuntimeExports = async (
  fixture: Awaited<ReturnType<typeof analyzeVersions>>,
  expected: (count: number) => unknown,
): Promise<void> => {
  // Execute only source-owned fixtures as an independent runtime oracle.
  for (const [path, exportName, count] of [
    [fixture.leftPath, fixture.input.left_export_name, 1],
    [fixture.rightPath, fixture.input.right_export_name, 2],
  ] as const)
    expect(await runtimeExport(path, exportName)).toEqual(expected(count));
};

const expectExportedCallableBinding = (
  evidence: unknown,
  localName: string,
): void => {
  const analysis = z
    .object({
      normalized_result: javascriptApplicationAnalysisResultSchema,
    })
    .parse(evidence).normalized_result;
  const exportBinding = analysis.graph.nodes
    .flatMap(({ observations }) => observations)
    .find(
      ({ properties }) =>
        properties.semantic_role === "export-binding" &&
        properties.exported_name === "default",
    );
  expect(exportBinding?.properties.local_name).toBe(localName);
  expect(analysis.semantic_graph.nodes).toEqual(
    expect.arrayContaining([
      expect.objectContaining({ kind: "function", label: localName }),
    ]),
  );
};

const expectUnresolvedExportBinding = (
  evidence: unknown,
  exportName: string,
): void => {
  const analysis = z
    .object({
      normalized_result: javascriptApplicationAnalysisResultSchema,
    })
    .parse(evidence).normalized_result;
  const observations = analysis.graph.nodes.flatMap(
    ({ observations }) => observations,
  );
  expect(
    observations.filter(
      ({ properties }) =>
        properties.semantic_role === "export-binding" &&
        properties.exported_name === exportName,
    ),
  ).not.toHaveLength(0);
  expect(
    observations.filter(
      ({ properties }) =>
        properties.semantic_role === "export-return-shapes" &&
        properties.exported_name === exportName,
    ),
  ).toEqual([]);
};

const expectUncertainComparison = (
  result: Awaited<ReturnType<typeof compareThroughCli>>,
): void => {
  expect(result).toMatchObject({
    left: { status: "unavailable" },
    right: { status: "unavailable" },
    summary: { added: 0, removed: 0, changed: 0, unknown: 1 },
    changes: [{ status: "unknown", path: "" }],
    coverage: { status: "partial" },
  });
  expect(result.property_inventories).toEqual([]);
};

const expectCountChange = (
  result: Awaited<ReturnType<typeof compareThroughCli>>,
): void => {
  expect(result).toMatchObject({
    left: { status: "selected" },
    right: { status: "selected" },
    summary: { added: 0, removed: 0, changed: 1, unknown: 0 },
    changes: [
      {
        path: "/count",
        status: "changed",
        left: { availability: "literal", value: 1 },
        right: { availability: "literal", value: 2 },
      },
    ],
    coverage: { status: "complete-within-inputs" },
  });
};

const runCli = async (args: readonly string[]): Promise<unknown> => {
  cliSession ??= startCompiledCliSession();
  return cliSession.run(args);
};

const analyzeVersions = async (
  source: (count: number) => string,
  exportName: string,
  fileName = "app.mjs",
) => {
  const root = await createTestTempDirectory("rea-exported-function-bindings-");
  const leftRoot = join(root, "left");
  const rightRoot = join(root, "right");
  await Promise.all([mkdir(leftRoot), mkdir(rightRoot)]);
  const leftPath = join(leftRoot, fileName);
  const rightPath = join(rightRoot, fileName);
  await Promise.all([
    writeFile(leftPath, source(1)),
    writeFile(rightPath, source(2)),
  ]);
  const [left, right] = await Promise.all([
    analyzeThroughMcp(leftRoot),
    analyzeThroughMcp(rightRoot),
  ]);
  return {
    root,
    leftPath,
    rightPath,
    input: {
      left,
      right,
      left_module_path: fileName,
      left_export_name: exportName,
      right_module_path: fileName,
      right_export_name: exportName,
    },
  };
};

const analyzeThroughMcp = async (inputPath: string) => {
  const client = await getMcpClient();
  const response = await client.callTool({
    name: "analyze_javascript_application",
    arguments: { input_path: inputPath, format: "auto" },
  });
  expect(response.isError).not.toBe(true);
  return response.structuredContent;
};

const expectCliAnalysisParity = async (
  fixture: Awaited<ReturnType<typeof analyzeVersions>>,
): Promise<void> => {
  for (const [root, evidence] of [
    [join(fixture.root, "left"), fixture.input.left],
    [join(fixture.root, "right"), fixture.input.right],
  ] as const) {
    const cli = applicationEnvelope.parse(
      await runCli(["analyze-javascript-application", root, "--json"]),
    );
    const mcp = applicationEnvelope.parse(evidence);
    expect(cli.normalized_result).toEqual(mcp.normalized_result);
  }
};

const compareThroughCli = async (
  fixture: Awaited<ReturnType<typeof analyzeVersions>>,
) => {
  const inputPath = join(fixture.root, "comparison.json");
  await writeFile(inputPath, JSON.stringify(fixture.input));
  return comparisonEnvelope.parse(
    await runCli(["compare-javascript-export-shapes", inputPath, "--json"]),
  ).normalized_result;
};

const compareThroughMcp = async (input: Record<string, unknown>) => {
  const client = await getMcpClient();
  const response = await client.callTool({
    name: "compare_javascript_export_shapes",
    arguments: input,
  });
  expect(response.isError).not.toBe(true);
  await client.ping();
  return comparisonEnvelope.parse(response.structuredContent).normalized_result;
};

const getMcpClient = async (): Promise<Client> => {
  if (mcpConnection === undefined) {
    const transport = new StdioClientTransport({
      command: process.execPath,
      args: [resolve("scripts/rea.mjs"), "mcp"],
      cwd: process.cwd(),
      env: { PATH: process.env.PATH ?? "", REA_LOG_LEVEL: "silent" },
      stderr: "pipe",
    });
    transport.stderr?.on("data", () => undefined);
    const client = new Client({
      name: "exported-function-bindings",
      version: "1",
    });
    mcpConnection = {
      client,
      transport,
      ready: client.connect(transport),
    };
  }
  await mcpConnection.ready;
  return mcpConnection.client;
};

const runtimeExport = async (
  path: string,
  exportName: string,
): Promise<unknown> => {
  const { stdout } = await execute(process.execPath, [
    "--input-type=module",
    "-e",
    `import { pathToFileURL } from 'node:url';
     const module = await import(pathToFileURL(process.argv[1]).href);
     const value = module[process.argv[2]];
     console.log(JSON.stringify({ value: typeof value === 'function' ? value() : value }));`,
    path,
    exportName,
  ]);
  return z.object({ value: z.unknown().optional() }).parse(JSON.parse(stdout))
    .value;
};