Handle NaN/Infinity in flushBatch; add NaN regression test

Per CodeRabbit's follow-up finding: the `<= 0` guard in flushBatch
caught the mid-flight 0 case, but not NaN. `NaN <= 0` is false, so
a NaN batch size would fall through to `splice(0, NaN)`, which
coerces to `splice(0, 0)` — reinstating the exact infinite
reschedule loop we were trying to prevent.

Switch to `Math.trunc` + `Number.isFinite` so any non-positive or
non-finite value routes through `flushAll`. Added a regression
test covering the NaN case.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: 2 people

packages/utils.jsx/spec/jsxCleanBehaviors.ts

@@ -102,16 +102,24 @@ describe('jsxClean queue', function () {
     it('drains synchronously if batchSize is flipped to 0 while a timer is pending', function () {
       const nodes = [makeNode(), makeNode(), makeNode()]
       for (const n of nodes) queueCleanNode(n)
-      assert.lengthOf(cleaned, 0)
       assert.equal(clock.countTimers(), 1)
 
-      // Consumer flips to sync mid-flight. When the timer fires it must
-      // fall through to a full drain — not splice(0, 0) forever.
       options.jsxCleanBatchSize = 0
       clock.tick(25)
 
       assert.deepEqual(cleaned, nodes)
       assert.equal(clock.countTimers(), 0, 'no re-armed timer')
     })
+
+    it('drains synchronously if batchSize becomes non-finite while a timer is pending', function () {
+      const nodes = [makeNode(), makeNode()]
+      for (const n of nodes) queueCleanNode(n)
+
+      options.jsxCleanBatchSize = Number.NaN as unknown as number
+      clock.tick(25)
+
+      assert.deepEqual(cleaned, nodes)
+      assert.equal(clock.countTimers(), 0)
+    })
   })
 })

packages/utils.jsx/src/jsxClean.ts

@@ -33,14 +33,15 @@ function scheduleBatch() {
 
 function flushBatch() {
   cleanNodeTimeoutID = null
-  // If the option was flipped to 0 (or below) while the timer was pending,
-  // fall through to synchronous drain. Otherwise splice(0, 0) would remove
-  // nothing and scheduleBatch would re-arm the timer every 25ms forever.
-  if (options.jsxCleanBatchSize <= 0) {
+  // If the option was flipped to a non-positive / non-finite value while the
+  // timer was pending, fall through to synchronous drain — otherwise
+  // splice(0, <=0|NaN) removes nothing and scheduleBatch re-arms forever.
+  const batchSize = Math.trunc(options.jsxCleanBatchSize)
+  if (!Number.isFinite(batchSize) || batchSize <= 0) {
     flushAll()
     return
   }
-  const nodes = cleanNodeQueue.splice(0, options.jsxCleanBatchSize)
+  const nodes = cleanNodeQueue.splice(0, batchSize)
   for (const node of nodes) {
     cleanNode(node)
   }