reverse-engineering-anything/tests/boundary/cli/jsonOutput.test.ts

import { constants } from "node:buffer";
import { createHash } from "node:crypto";
import { Writable } from "node:stream";

import { Cli } from "incur";
import { describe, expect, it } from "vitest";

import { writeJsonOutput } from "../../../src/cli/jsonOutput.js";
import {
  createStreamedCliJsonOutput,
  streamCliCommandResults,
} from "../../../src/cli/streamedJsonOutput.js";
import { registerManagedCommands } from "../../../src/cli/managedCommands.js";
import { silentLogger } from "../../../src/logger.js";

const collect = async (
  value: unknown,
  format: "json" | "jsonl" = "json",
): Promise<string> => {
  const chunks: Buffer[] = [];
  const destination = new Writable({
    write(chunk: unknown, _encoding, callback) {
      if (!Buffer.isBuffer(chunk)) {
        callback(new TypeError("Expected a UTF-8 output buffer"));
        return;
      }
      chunks.push(chunk);
      callback();
    },
  });
  await writeJsonOutput(value, destination, format);
  return Buffer.concat(chunks).toString("utf8");
};

describe("incremental CLI JSON", () => {
  it.each([
    null,
    true,
    -0,
    1e-7,
    "",
    { empty: [], object: {}, nested: [{ value: null }] },
    { 'quoted"key': '\u0000\b\t\n\f\r\\"', unicode: "雪𝟠\ud800\udfff" },
    { text: `${"x".repeat(8191)}𝟠${"y".repeat(8191)}\ud800` },
  ])("matches native JSON encoding for %j", async (value) => {
    expect(await collect(value)).toBe(`${JSON.stringify(value, null, 2)}\n`);
  });

  it("preserves shared objects without interpreting them as cycles", async () => {
    const shared = { value: "shared" };
    const value = { copies: [shared, shared] };
    expect(await collect(value)).toBe(`${JSON.stringify(value, null, 2)}\n`);
  });

  it("writes compact JSONL records and preserves an empty record set", async () => {
    const value = [{ text: "first\nrecord" }, { text: "雪𝟠" }];
    expect(await collect(value, "jsonl")).toBe(
      `${value.map((item) => JSON.stringify(item)).join("\n")}\n`,
    );
    expect(await collect([], "jsonl")).toBe("");
  });

  it("bounds escaped leaf writes and waits for a slow destination", async () => {
    const leaf = `\u0000雪𝟠`.repeat(32 * 1024);
    const chunks: Buffer[] = [];
    let largestChunk = 0;
    const destination = new Writable({
      highWaterMark: 1,
      write(chunk: unknown, _encoding, callback) {
        if (!Buffer.isBuffer(chunk)) {
          callback(new TypeError("Expected UTF-8 bytes"));
          return;
        }
        largestChunk = Math.max(largestChunk, chunk.length);
        setTimeout(() => {
          chunks.push(chunk);
          callback();
        }, 1);
      },
    });
    await writeJsonOutput({ leaf }, destination);
    expect(largestChunk).toBeLessThan(Buffer.byteLength(leaf));
    const actual = Buffer.concat(chunks).toString("utf8");
    const expected = `${JSON.stringify({ leaf }, null, 2)}\n`;
    expect(actual.length).toBe(expected.length);
    expect(actual === expected).toBe(true);
    expect(destination.writableEnded).toBe(false);
  });

  it("waits for the final write even when it fits the destination buffer", async () => {
    let completed = false;
    const destination = new Writable({
      write(_chunk, _encoding, callback) {
        setTimeout(() => {
          completed = true;
          callback();
        }, 5);
      },
    });
    await writeJsonOutput({ result: "small" }, destination);
    expect(completed).toBe(true);
  });

  it.each([false, true])(
    "propagates a failed destination (deferred: %s)",
    async (deferred) => {
      const cause = new Error("Fixture destination failed");
      const destination = new Writable({
        write(_chunk, _encoding, callback) {
          if (deferred) setTimeout(() => callback(cause), 5);
          else callback(cause);
        },
      });
      await expect(
        writeJsonOutput({ result: "small" }, destination),
      ).rejects.toBe(cause);
    },
  );

  it("leaves a reusable destination open without adding error listeners", async () => {
    const destination = new Writable({
      write(_chunk, _encoding, callback) {
        callback();
      },
    });
    const listeners = destination.listenerCount("error");
    await writeJsonOutput({ result: "first" }, destination);
    await writeJsonOutput({ result: "second" }, destination);
    expect(destination.listenerCount("error")).toBe(listeners);
    expect(destination.writableEnded).toBe(false);
  });

  it("rejects a cycle at the serialization boundary", async () => {
    const cycle: Record<string, unknown> = {};
    cycle.self = cycle;
    await expect(collect(cycle)).rejects.toThrow("circular reference");
  });

  it.each([undefined, Number.NaN, Number.POSITIVE_INFINITY, 1n, new Date(0)])(
    "rejects non-JSON input %s",
    async (value) => {
      await expect(collect(value)).rejects.toThrow("ordinary JSON");
    },
  );
});

describe("streamed CLI result surface", () => {
  it.each([
    [],
    ["--format", "md"],
    ["--json", "--token-limit", "5"],
    ["--json", "--format", "invalid"],
  ])("delegates unsupported output controls %j", (...arguments_) => {
    expect(createStreamedCliJsonOutput(arguments_, new Writable())).toBe(
      undefined,
    );
  });

  it("keeps ownership after a failed write so no second document is emitted", async () => {
    const cause = new Error("Fixture destination failed");
    const destination = new Writable({
      write(_chunk, _encoding, callback) {
        callback(cause);
      },
    });
    const output = createStreamedCliJsonOutput(["--json"], destination);
    if (output === undefined) throw new Error("Missing JSON output surface");
    await expect(
      output.write(
        { result: "small" },
        { command: "fixture", duration: "1ms", format: "json" },
      ),
    ).rejects.toBe(cause);
    expect(output.handled).toBe(true);
    expect(output.failed).toBe(true);
  });

  it("streams managed command output past the engine string limit and declines oversized token counting", async () => {
    const leaf = "x".repeat(64 * 1024);
    const count = Math.ceil(constants.MAX_STRING_LENGTH / leaf.length) + 1;
    const value = { methods: Array.from({ length: count }, () => leaf) };
    const expected = createHash("sha256");
    const encodedLeaf = JSON.stringify(leaf);
    const prefix = '{\n  "methods": [\n    ';
    const separator = ",\n    ";
    const suffix = "\n  ]\n}\n";
    expected.update(prefix);
    for (let index = 0; index < count; index += 1) {
      if (index > 0) expected.update(separator);
      expected.update(encodedLeaf);
    }
    expected.update(suffix);
    const expectedCharacters =
      prefix.length +
      count * encodedLeaf.length +
      (count - 1) * separator.length +
      suffix.length;
    expect(expectedCharacters).toBeGreaterThan(constants.MAX_STRING_LENGTH);

    const actual = createHash("sha256");
    let bytes = 0;
    const destination = new Writable({
      write(chunk: Buffer, _encoding, callback) {
        bytes += chunk.length;
        actual.update(chunk);
        callback();
      },
    });
    const cli = Cli.create("rea-output-test", { sync: false });
    registerManagedCommands(cli, silentLogger, async (path, operation) => {
      expect(path).toBe("fixture.dll");
      expect(operation).toBe("inspect_managed_members");
      return value;
    });
    const argv = ["inspect-managed-members", "fixture.dll", "--json"];
    const output = createStreamedCliJsonOutput(argv, destination);
    if (output === undefined) throw new Error("Missing JSON output surface");
    streamCliCommandResults(cli, output);
    let exitCode = 0;
    let fallbackBytes = 0;
    await cli.serve(argv, {
      stdout: (text) => {
        if (!output.handled) fallbackBytes += text.length;
      },
      exit: (code) => {
        exitCode = code;
      },
    });
    expect(exitCode).toBe(0);
    expect(fallbackBytes).toBe(0);
    expect(bytes).toBe(expectedCharacters);
    expect(actual.digest("hex")).toBe(expected.digest("hex"));

    const chunks: Buffer[] = [];
    const tokenArgv = [...argv, "--token-count", "--full-output"];
    const tokenOutput = createStreamedCliJsonOutput(
      tokenArgv,
      new Writable({
        write(chunk: Buffer, _encoding, callback) {
          chunks.push(chunk);
          callback();
        },
      }),
    );
    if (tokenOutput === undefined)
      throw new Error("Missing token-count output surface");
    const tokenCli = Cli.create("rea-output-test", { sync: false });
    registerManagedCommands(tokenCli, silentLogger, async () => value);
    streamCliCommandResults(tokenCli, tokenOutput);
    await tokenCli.serve(tokenArgv, {
      stdout: (text) => {
        if (!tokenOutput.handled) fallbackBytes += text.length;
      },
      exit: (code) => {
        exitCode = code;
      },
    });
    expect(exitCode).toBe(1);
    expect(fallbackBytes).toBe(0);
    expect(JSON.parse(Buffer.concat(chunks).toString("utf8"))).toMatchObject({
      ok: false,
      error: {
        code: "resource_constraint",
        remediation: {
          action: expect.stringContaining("Remove --token-count"),
        },
        details: {
          reported_limits: {
            formatted_characters: expectedCharacters - 1,
            max_string_characters: constants.MAX_STRING_LENGTH,
          },
        },
      },
      meta: { command: "inspect-managed-members" },
    });
  }, 60_000);
});