Fix hydration-susepsnse crashing due to sCU bail

[JoviDeCroock]

1. During hydration, the Suspense child throws a promise.
2. Suspense preserves the existing server DOM instead of showing the fallback.
3. Because the component threw before diffChildren() ran, its vnode can be left with _children === null.
4. That vnode becomes the oldVNode on the next update.
5. The parent update reaches the suspended child, and shouldComponentUpdate() === false takes the bailout path.
6. The bailout does:

  newVNode._children = oldVNode._children;
  newVNode._children.some(...)

but oldVNode._children is null, so it crashes.
7. The fix makes the recovery path establish the invariant that recovered vnodes always have iterable _children: partial children if already produced, old children if available, otherwise [].

[github-actions]

📊 Tachometer Benchmark Results

Summary

duration

• create10k: unsure 🔍 -0% - +1% (-3.16ms - +3.83ms)
  ^{preact-local vs preact-main}
• filter-list: unsure 🔍 -0% - +1% (-0.07ms - +0.22ms)
  ^{preact-local vs preact-main}
• hydrate1k: unsure 🔍 -1% - +3% (-0.42ms - +1.68ms)
  ^{preact-local vs preact-main}
• many-updates: unsure 🔍 -1% - +3% (-0.19ms - +0.41ms)
  ^{preact-local vs preact-main}
• replace1k: unsure 🔍 -1% - +3% (-0.36ms - +1.42ms)
  ^{preact-local vs preact-main}
• text-update: unsure 🔍 -2% - +6% (-0.04ms - +0.12ms)
  ^{preact-local vs preact-main}
• todo: unsure 🔍 -3% - +1% (-0.73ms - +0.24ms)
  ^{preact-local vs preact-main}
• update10th1k: unsure 🔍 -5% - +2% (-1.49ms - +0.73ms)
  ^{preact-local vs preact-main}

usedJSHeapSize

• create10k: unsure 🔍 -0% - +0% (-0.00ms - +0.00ms)
  ^{preact-local vs preact-main}
• filter-list: unsure 🔍 -0% - +0% (-0.00ms - +0.00ms)
  ^{preact-local vs preact-main}
• hydrate1k: unsure 🔍 -5% - +1% (-0.24ms - +0.04ms)
  ^{preact-local vs preact-main}
• many-updates: unsure 🔍 -0% - +0% (-0.00ms - +0.00ms)
  ^{preact-local vs preact-main}
• replace1k: unsure 🔍 -0% - +0% (-0.00ms - +0.01ms)
  ^{preact-local vs preact-main}
• text-update: slower ❌ 0% - 7% (0.00ms - 0.07ms)
  ^{preact-local vs preact-main}
• todo: unsure 🔍 -0% - +0% (-0.00ms - +0.00ms)
  ^{preact-local vs preact-main}
• update10th1k: unsure 🔍 -0% - +0% (-0.01ms - +0.00ms)
  ^{preact-local vs preact-main}

Results

create10k

• Browser: chrome-headless
• Sample size: 50
• Built by: CI #5619

• Commit: c3b4f0f

duration

Version	Avg time	vs preact-local	vs preact-main
preact-local	753.58ms - 758.77ms	-	unsure 🔍 -0% - +1% -3.16ms - +3.83ms
preact-main	753.50ms - 758.18ms	unsure 🔍 -1% - +0% -3.83ms - +3.16ms	-

usedJSHeapSize

Version	Avg time	vs preact-local	vs preact-main
preact-local	19.21ms - 19.21ms	-	unsure 🔍 -0% - +0% -0.00ms - +0.00ms
preact-main	19.21ms - 19.21ms	unsure 🔍 -0% - +0% -0.00ms - +0.00ms	-

filter-list

• Browser: chrome-headless
• Sample size: 50
• Built by: CI #5619

• Commit: c3b4f0f

duration

Version	Avg time	vs preact-local	vs preact-main
preact-local	16.45ms - 16.73ms	-	unsure 🔍 -0% - +1% -0.07ms - +0.22ms
preact-main	16.48ms - 16.55ms	unsure 🔍 -1% - +0% -0.22ms - +0.07ms	-

usedJSHeapSize

Version	Avg time	vs preact-local	vs preact-main
preact-local	1.56ms - 1.56ms	-	unsure 🔍 -0% - +0% -0.00ms - +0.00ms
preact-main	1.56ms - 1.56ms	unsure 🔍 -0% - +0% -0.00ms - +0.00ms	-

hydrate1k

• Browser: chrome-headless
• Sample size: 70
• Built by: CI #5619

• Commit: c3b4f0f

duration

Version	Avg time	vs preact-local	vs preact-main
preact-local	59.97ms - 61.61ms	-	unsure 🔍 -1% - +3% -0.42ms - +1.68ms
preact-main	59.50ms - 60.82ms	unsure 🔍 -3% - +1% -1.68ms - +0.42ms	-

usedJSHeapSize

Version	Avg time	vs preact-local	vs preact-main
preact-local	5.08ms - 5.22ms	-	unsure 🔍 -5% - +1% -0.24ms - +0.04ms
preact-main	5.13ms - 5.37ms	unsure 🔍 -1% - +5% -0.04ms - +0.24ms	-

many-updates

• Browser: chrome-headless
• Sample size: 50
• Built by: CI #5619

• Commit: c3b4f0f

duration

Version	Avg time	vs preact-local	vs preact-main
preact-local	15.99ms - 16.37ms	-	unsure 🔍 -1% - +3% -0.19ms - +0.41ms
preact-main	15.84ms - 16.30ms	unsure 🔍 -3% - +1% -0.41ms - +0.19ms	-

usedJSHeapSize

Version	Avg time	vs preact-local	vs preact-main
preact-local	3.73ms - 3.74ms	-	unsure 🔍 -0% - +0% -0.00ms - +0.00ms
preact-main	3.73ms - 3.74ms	unsure 🔍 -0% - +0% -0.00ms - +0.00ms	-

replace1k

• Browser: chrome-headless
• Sample size: 100
• Built by: CI #5619

• Commit: c3b4f0f

duration

Version	Avg time	vs preact-local	vs preact-main
preact-local	55.52ms - 56.89ms	-	unsure 🔍 -1% - +3% -0.36ms - +1.42ms
preact-main	55.11ms - 56.25ms	unsure 🔍 -3% - +1% -1.42ms - +0.36ms	-

usedJSHeapSize

Version	Avg time	vs preact-local	vs preact-main
preact-local	3.02ms - 3.02ms	-	unsure 🔍 -0% - +0% -0.00ms - +0.01ms
preact-main	3.02ms - 3.02ms	unsure 🔍 -0% - +0% -0.01ms - +0.00ms	-

run-warmup-0

Version	Avg time	vs preact-local	vs preact-main
preact-local	26.41ms - 27.16ms	-	unsure 🔍 -3% - +1% -0.87ms - +0.26ms
preact-main	26.67ms - 27.51ms	unsure 🔍 -1% - +3% -0.26ms - +0.87ms	-

run-warmup-1

Version	Avg time	vs preact-local	vs preact-main
preact-local	31.20ms - 32.16ms	-	unsure 🔍 -1% - +4% -0.16ms - +1.19ms
preact-main	30.69ms - 31.64ms	unsure 🔍 -4% - +0% -1.19ms - +0.16ms	-

run-warmup-2

Version	Avg time	vs preact-local	vs preact-main
preact-local	31.36ms - 32.43ms	-	unsure 🔍 -3% - +2% -0.82ms - +0.74ms
preact-main	31.37ms - 32.50ms	unsure 🔍 -2% - +3% -0.74ms - +0.82ms	-

run-warmup-3

Version	Avg time	vs preact-local	vs preact-main
preact-local	25.41ms - 26.38ms	-	unsure 🔍 -1% - +3% -0.37ms - +0.75ms
preact-main	25.43ms - 25.98ms	unsure 🔍 -3% - +1% -0.75ms - +0.37ms	-

run-warmup-4

Version	Avg time	vs preact-local	vs preact-main
preact-local	22.31ms - 23.36ms	-	unsure 🔍 -3% - +4% -0.74ms - +0.80ms
preact-main	22.23ms - 23.37ms	unsure 🔍 -4% - +3% -0.80ms - +0.74ms	-

run-final

Version	Avg time	vs preact-local	vs preact-main
preact-local	20.96ms - 21.39ms	-	unsure 🔍 -1% - +2% -0.28ms - +0.36ms
preact-main	20.90ms - 21.37ms	unsure 🔍 -2% - +1% -0.36ms - +0.28ms	-

text-update

• Browser: chrome-headless
• Sample size: 220
• Built by: CI #5619

• Commit: c3b4f0f

duration

Version	Avg time	vs preact-local	vs preact-main
preact-local	1.88ms - 1.98ms	-	unsure 🔍 -2% - +6% -0.04ms - +0.12ms
preact-main	1.83ms - 1.95ms	unsure 🔍 -6% - +2% -0.12ms - +0.04ms	-

usedJSHeapSize

Version	Avg time	vs preact-local	vs preact-main
preact-local	1.04ms - 1.10ms	-	slower ❌ 0% - 7% 0.00ms - 0.07ms
preact-main	1.01ms - 1.05ms	faster ✔ 0% - 7% 0.00ms - 0.07ms	-

todo

• Browser: chrome-headless
• Sample size: 50
• Built by: CI #5619

• Commit: c3b4f0f

duration

Version	Avg time	vs preact-local	vs preact-main
preact-local	25.60ms - 26.02ms	-	unsure 🔍 -3% - +1% -0.73ms - +0.24ms
preact-main	25.62ms - 26.49ms	unsure 🔍 -1% - +3% -0.24ms - +0.73ms	-

usedJSHeapSize

Version	Avg time	vs preact-local	vs preact-main
preact-local	1.26ms - 1.26ms	-	unsure 🔍 -0% - +0% -0.00ms - +0.00ms
preact-main	1.26ms - 1.26ms	unsure 🔍 -0% - +0% -0.00ms - +0.00ms	-

update10th1k

• Browser: chrome-headless
• Sample size: 60
• Built by: CI #5619

• Commit: c3b4f0f

duration

Version	Avg time	vs preact-local	vs preact-main
preact-local	30.04ms - 31.43ms	-	unsure 🔍 -5% - +2% -1.49ms - +0.73ms
preact-main	30.25ms - 31.98ms	unsure 🔍 -2% - +5% -0.73ms - +1.49ms	-

usedJSHeapSize

Version	Avg time	vs preact-local	vs preact-main
preact-local	2.98ms - 2.99ms	-	unsure 🔍 -0% - +0% -0.01ms - +0.00ms
preact-main	2.98ms - 3.00ms	unsure 🔍 -0% - +0% -0.00ms - +0.01ms	-

_{tachometer-reporter-action v2 for CI}

[github-actions]

Size Change: -20 B (-0.03%)

Total Size: 79.6 kB

📦 View Changed

Filename	Size	Change
compat/dist/compat.js	4.22 kB	+8 B (+0.19%)
compat/dist/compat.mjs	4.15 kB	+7 B (+0.17%)
compat/dist/compat.module.js	4.15 kB	+7 B (+0.17%)
compat/dist/compat.umd.js	4.29 kB	+15 B (+0.35%)
dist/preact.js	4.83 kB	-6 B (-0.12%)
dist/preact.min.js	4.84 kB	-10 B (-0.21%)
dist/preact.min.module.js	4.85 kB	-7 B (-0.14%)
dist/preact.min.umd.js	4.86 kB	-9 B (-0.18%)
dist/preact.mjs	4.85 kB	-7 B (-0.14%)
dist/preact.module.js	4.85 kB	-7 B (-0.14%)
dist/preact.umd.js	4.87 kB	-11 B (-0.23%)

ℹ️ View Unchanged

Filename	Size
debug/dist/debug.js	3.85 kB
debug/dist/debug.mjs	3.85 kB
debug/dist/debug.module.js	3.85 kB
debug/dist/debug.umd.js	3.93 kB
devtools/dist/devtools.js	260 B
devtools/dist/devtools.mjs	274 B
devtools/dist/devtools.module.js	274 B
devtools/dist/devtools.umd.js	346 B
hooks/dist/hooks.js	1.51 kB
hooks/dist/hooks.mjs	1.54 kB
hooks/dist/hooks.module.js	1.54 kB
hooks/dist/hooks.umd.js	1.58 kB
jsx-runtime/dist/jsxRuntime.js	1.01 kB
jsx-runtime/dist/jsxRuntime.mjs	985 B
jsx-runtime/dist/jsxRuntime.module.js	985 B
jsx-runtime/dist/jsxRuntime.umd.js	1.08 kB
test-utils/dist/testUtils.js	473 B
test-utils/dist/testUtils.mjs	477 B
test-utils/dist/testUtils.module.js	477 B
test-utils/dist/testUtils.umd.js	555 B

_{compressed-size-action}