runner@runnervm7b5n9:~/work/qwen-code/qwen-code$ echo '=== BEFORE: source on main (HEAD) ===' && git show HEAD:packages/acp-bridge/src/bridge.ts | sed -n '710,735p'
=== BEFORE: source on main (HEAD) ===
  //                    guard is fail-OPEN behavior — we'd rather fail
  //                    boot than serve unbounded.
  let maxSessions: number;
  if (opts.maxSessions === undefined) {
    maxSessions = DEFAULT_MAX_SESSIONS;
  } else if (Number.isNaN(opts.maxSessions)) {
    throw new TypeError(
      `Invalid maxSessions: NaN. Must be a number >= 0 ` +
        `(0 / Infinity = unlimited).`,
    );
  } else if (opts.maxSessions < 0) {
    throw new TypeError(
      `Invalid maxSessions: ${opts.maxSessions}. Must be >= 0 ` +
        `(0 / Infinity = unlimited).`,
    );
  } else if (opts.maxSessions === 0 || opts.maxSessions === Infinity) {
    maxSessions = Infinity;
  } else {
    maxSessions = opts.maxSessions;
  }

runner@runnervm7b5n9:~/work/qwen-code/qwen-code$ echo '=== AFTER: source on PR branch (worktree) ===' && sed -n '710,735p' .qwen/worktrees/triage/packages/acp-bridge/src/bridge.ts
=== AFTER: source on PR branch (worktree) ===
  // `0` → explicitly unlimited (operator opt-out).
  // `Infinity` → unlimited (programmatic opt-out — accepted as a
  //              long-standing alias since the cap check is `>= max`).
  // non-integer / `NaN` / negative → throw. A typo / parse error in
  //                    CLI/config silently disabling or rounding the
  //                    daemon's only resource guard is fail-OPEN behavior —
  //                    we'd rather fail boot than serve with the wrong cap.
  let maxSessions: number;
  if (opts.maxSessions === undefined) {
    maxSessions = DEFAULT_MAX_SESSIONS;
  } else if (opts.maxSessions === 0 || opts.maxSessions === Infinity) {
    maxSessions = Infinity;
  } else if (
    !Number.isFinite(opts.maxSessions) ||
    !Number.isInteger(opts.maxSessions) ||
    opts.maxSessions < 0
  ) {
    throw new TypeError(
      `Invalid maxSessions: ${opts.maxSessions}. ` +
        `Must be a non-negative integer ` +
        `(0 / Infinity = unlimited).`,
    );
  } else {
    maxSessions = opts.maxSessions;
  }

runner@runnervm7b5n9:~/work/qwen-code/qwen-code$ echo '=== probe: same inputs against OLD vs NEW validation ===' && node /tmp/probe-maxsessions.js 2>&1 | tee tmp/$S/probe.log
=== probe: same inputs against OLD vs NEW validation ===
input                            | OLD (HEAD)     | NEW (PR #5705)
---------------------------------|----------------|----------------
undefined (default)              | 20             | 20
0 (unlimited sentinel)           | Infinity (unlimited) | Infinity (unlimited)
Infinity (unlimited sentinel)    | Infinity (unlimited) | Infinity (unlimited)
7 (valid integer)                | 7              | 7
NaN                              | THROWS: Invalid maxSessions: NaN | THROWS: Invalid maxSessions: NaN
-5 (negative)                    | THROWS: Invalid maxSessions: -5 | THROWS: Invalid maxSessions: -5
1.5 (fractional — the bug)       | 1.5            | THROWS: Invalid maxSessions: 1
2.9999 (fractional)              | 2.9999         | THROWS: Invalid maxSessions: 2

--- effective session cap check (current >= maxSessions) ---
maxSessions=1  →  cap=1  | session#1=deny, session#2=deny
maxSessions=1.5  →  cap=1.5  | session#1=allow, session#2=deny
maxSessions=2  →  cap=2  | session#1=allow, session#2=deny

runner@runnervm7b5n9:~/work/qwen-code/qwen-code/.qwen/worktrees/triage/packages/acp-bridge$ echo '=== vitest: NEW tests against OLD bridge.ts (should FAIL) ===' && /home/runner/work/qwen-code/qwen-code/node_modules/.bin/vitest run src/bridge.test.ts -t 'maxSessions' 2>&1 | tee /home/runner/work/qwen-code/qwen-code/tmp/$S/vitest-old.log
=== vitest: NEW tests against OLD bridge.ts (should FAIL) ===

⎯⎯⎯⎯⎯⎯⎯ Failed Tests 1 ⎯⎯⎯⎯⎯⎯⎯

 FAIL  src/bridge.test.ts > createAcpSessionBridge > opts validation > rejects invalid maxSessions (float)
AssertionError: expected [Function] to throw an error

- Expected:
null

+ Received:
undefined

 ❯ src/bridge.test.ts:4703:56
    4701|       // NOT silently disable the daemon's resource cap. We fail
    4702|       // boot loud instead of serving unbounded.
    4703|       expect(() => makeBridge({ maxSessions: value })).toThrow(/maxSes…
       |                                                        ^

 Test Files  1 failed (1)
      Tests  1 failed | 16 passed | 282 skipped (299)

runner@runnervm7b5n9:~/work/qwen-code/qwen-code/.qwen/worktrees/triage/packages/acp-bridge$ echo '=== vitest: NEW tests against NEW bridge.ts (should PASS) ===' && /home/runner/work/qwen-code/qwen-code/node_modules/.bin/vitest run src/bridge.test.ts -t 'maxSessions' 2>&1 | tee /home/runner/work/qwen-code/qwen-code/tmp/$S/vitest-new.log
=== vitest: NEW tests against NEW bridge.ts (should PASS) ===
 ✓ src/bridge.test.ts (299 tests | 282 skipped) 54ms

 Test Files  1 passed (1)
      Tests  17 passed | 282 skipped (299)

runner@runnervm7b5n9:~/work/qwen-code/qwen-code/.qwen/worktrees/triage/packages/acp-bridge$ /home/runner/work/qwen-code/qwen-code/node_modules/.bin/vitest run src/bridge.test.ts
 ✓ src/bridge.test.ts (299 tests) 2851ms

 Test Files  1 passed (1)
      Tests  299 passed (299)