chore: avoid microtasks when flushing sync

[trueadm]

This has a significant impact on our benchmark suite because we avoid creating microtasks in a sync benchmark. We previously had this logic in the codebase but it was removed in #15348

Main:

{
  benchmark: 'sbench_create_signals',
  time: '401.26',
  gc_time: '29.60'
}
{ benchmark: 'sbench_create_0to1', time: '8.17', gc_time: '0.00' }
{ benchmark: 'sbench_create_1to1', time: '29.06', gc_time: '0.59' }
{ benchmark: 'sbench_create_2to1', time: '27.08', gc_time: '0.52' }
{ benchmark: 'sbench_create_4to1', time: '25.51', gc_time: '0.61' }
{ benchmark: 'sbench_create_1000to1', time: '24.78', gc_time: '0.49' }
{ benchmark: 'sbench_create_1to2', time: '12.27', gc_time: '0.00' }
{ benchmark: 'sbench_create_1to4', time: '16.14', gc_time: '1.18' }
{ benchmark: 'sbench_create_1to8', time: '13.43', gc_time: '1.21' }
{ benchmark: 'sbench_create_1to1000', time: '4.89', gc_time: '0.00' }
{
  benchmark: 'kairo_avoidable_owned',
  time: '415.52',
  gc_time: '77.30'
}
{
  benchmark: 'kairo_avoidable_unowned',
  time: '507.39',
  gc_time: '73.81'
}
{ benchmark: 'kairo_broad_owned', time: '414.50', gc_time: '2.02' }
{ benchmark: 'kairo_broad_unowned', time: '413.50', gc_time: '2.16' }
{ benchmark: 'kairo_deep_owned', time: '181.87', gc_time: '1.93' }
{ benchmark: 'kairo_deep_unowned', time: '806.19', gc_time: '4.01' }
{ benchmark: 'kairo_diamond_owned', time: '340.28', gc_time: '34.45' }
{
  benchmark: 'kairo_diamond_unowned',
  time: '434.26',
  gc_time: '34.75'
}
{ benchmark: 'kairo_triangle_owned', time: '96.85', gc_time: '4.79' }
{
  benchmark: 'kairo_triangle_unowned',
  time: '198.79',
  gc_time: '4.57'
}
{ benchmark: 'kairo_mux_owned', time: '298.60', gc_time: '3.77' }
{ benchmark: 'kairo_mux_unowned', time: '450.16', gc_time: '3.95' }
{ benchmark: 'kairo_repeated_owned', time: '54.82', gc_time: '5.33' }
{ benchmark: 'kairo_repeated_unowned', time: '55.61', gc_time: '5.08' }
{ benchmark: 'kairo_unstable_owned', time: '88.33', gc_time: '5.46' }
{
  benchmark: 'kairo_unstable_unowned',
  time: '103.47',
  gc_time: '4.81'
}
{ benchmark: 'mol_bench_owned', time: '231.41', gc_time: '0.75' }
{ benchmark: 'mol_bench_unowned', time: '248.76', gc_time: '1.18' }

Finished reactivity benchmarks.

{ suite_time: '5902.90', suite_gc_time: '304.32' }

This PR:

{
  benchmark: 'sbench_create_signals',
  time: '295.67',
  gc_time: '79.27'
}
{ benchmark: 'sbench_create_0to1', time: '7.83', gc_time: '0.00' }
{ benchmark: 'sbench_create_1to1', time: '19.93', gc_time: '2.14' }
{ benchmark: 'sbench_create_2to1', time: '17.41', gc_time: '1.75' }
{ benchmark: 'sbench_create_4to1', time: '16.30', gc_time: '1.77' }
{ benchmark: 'sbench_create_1000to1', time: '14.97', gc_time: '2.05' }
{ benchmark: 'sbench_create_1to2', time: '9.86', gc_time: '0.60' }
{ benchmark: 'sbench_create_1to4', time: '19.46', gc_time: '6.63' }
{ benchmark: 'sbench_create_1to8', time: '15.18', gc_time: '3.71' }
{ benchmark: 'sbench_create_1to1000', time: '4.45', gc_time: '0.00' }
{ benchmark: 'kairo_avoidable_owned', time: '270.91', gc_time: '4.66' }
{
  benchmark: 'kairo_avoidable_unowned',
  time: '362.95',
  gc_time: '5.16'
}
{ benchmark: 'kairo_broad_owned', time: '408.44', gc_time: '0.00' }
{ benchmark: 'kairo_broad_unowned', time: '407.62', gc_time: '0.00' }
{ benchmark: 'kairo_deep_owned', time: '175.84', gc_time: '0.00' }
{ benchmark: 'kairo_deep_unowned', time: '805.32', gc_time: '0.00' }
{ benchmark: 'kairo_diamond_owned', time: '273.82', gc_time: '2.69' }
{ benchmark: 'kairo_diamond_unowned', time: '379.19', gc_time: '2.78' }
{ benchmark: 'kairo_triangle_owned', time: '87.13', gc_time: '0.41' }
{
  benchmark: 'kairo_triangle_unowned',
  time: '186.83',
  gc_time: '0.43'
}
{ benchmark: 'kairo_mux_owned', time: '291.71', gc_time: '1.28' }
{ benchmark: 'kairo_mux_unowned', time: '437.53', gc_time: '1.37' }
{ benchmark: 'kairo_repeated_owned', time: '44.12', gc_time: '0.21' }
{ benchmark: 'kairo_repeated_unowned', time: '45.87', gc_time: '0.21' }
{ benchmark: 'kairo_unstable_owned', time: '76.82', gc_time: '0.53' }
{ benchmark: 'kairo_unstable_unowned', time: '92.73', gc_time: '0.60' }
{ benchmark: 'mol_bench_owned', time: '230.92', gc_time: '0.24' }
{ benchmark: 'mol_bench_unowned', time: '248.28', gc_time: '0.39' }

Finished reactivity benchmarks.

{ suite_time: '5247.09', suite_gc_time: '118.88' }

[changeset-bot]

🦋 Changeset detected

Latest commit: 425a8d8

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
svelte	Patch

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[github-actions]

Playground

pnpm add https://pkg.pr.new/svelte@15855

[Rich-Harris]

with updated bench:compare

sbench_create_signals
  time: fastest is b (main)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 446.49ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 439.05ms
  gc_time: fastest is b (main)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 200.65ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 196.49ms
sbench_create_0to1
  time: fastest is b (main)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 5.00ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 4.89ms
sbench_create_1to1
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 21.81ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 22.16ms
  gc_time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 2.72ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 2.73ms
sbench_create_2to1
  time: fastest is b (main)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 19.73ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 19.48ms
  gc_time: fastest is b (main)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 2.80ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼  2.70ms
sbench_create_4to1
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 18.12ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 18.14ms
  gc_time: fastest is b (main)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 2.78ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼  2.70ms
sbench_create_1000to1
  time: fastest is b (main)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 16.78ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 16.64ms
  gc_time: fastest is b (main)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 2.82ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼  2.64ms
sbench_create_1to2
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼  10.25ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 10.61ms
  gc_time: fastest is b (main)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 0.65ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼  0.61ms
sbench_create_1to4
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼  8.36ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 8.78ms
  gc_time: fastest is b (main)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 0.52ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼   0.47ms
sbench_create_1to8
  time: fastest is b (main)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 6.36ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 6.29ms
sbench_create_1to1000
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼   4.65ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 5.04ms
kairo_avoidable_owned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼        288.04ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 459.60ms
  gc_time: fastest is a (flush-sync)
    a: ◼                    6.73ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 111.79ms
kairo_avoidable_unowned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼       385.36ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 554.96ms
  gc_time: fastest is a (flush-sync)
    a: ◼                    6.74ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 108.98ms
kairo_broad_owned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 431.42ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 434.66ms
kairo_broad_unowned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 431.44ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 433.16ms
kairo_deep_owned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼  189.10ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 194.03ms
kairo_deep_unowned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 921.25ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 928.12ms
kairo_diamond_owned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼      285.83ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 371.12ms
  gc_time: fastest is a (flush-sync)
    a: ◼                    4.03ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 56.06ms
kairo_diamond_unowned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼    394.52ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 471.91ms
  gc_time: fastest is a (flush-sync)
    a: ◼                    4.06ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 56.02ms
kairo_triangle_owned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼   93.83ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 106.47ms
  gc_time: fastest is a (flush-sync)
    a: ◼                    0.44ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 8.30ms
kairo_triangle_unowned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼  212.52ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 227.08ms
  gc_time: fastest is a (flush-sync)
    a: ◼                    0.45ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 9.08ms
kairo_mux_owned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼  313.04ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 322.66ms
  gc_time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼             2.13ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 5.12ms
kairo_mux_unowned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 470.57ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 481.98ms
  gc_time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼             2.18ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 5.36ms
kairo_repeated_owned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼     45.66ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 57.89ms
  gc_time: fastest is a (flush-sync)
    a: ◼                    0.25ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 7.72ms
kairo_repeated_unowned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼     46.50ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 59.80ms
  gc_time: fastest is a (flush-sync)
    a: ◼                    0.22ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 7.38ms
kairo_unstable_owned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼    79.44ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 91.97ms
  gc_time: fastest is a (flush-sync)
    a: ◼◼                   0.75ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 8.64ms
kairo_unstable_unowned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼   95.76ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 108.02ms
  gc_time: fastest is a (flush-sync)
    a: ◼◼◼                  0.89ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 6.66ms
mol_bench_owned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 278.60ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 281.32ms
mol_bench_unowned
  time: fastest is a (flush-sync)
    a: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 296.31ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 297.55ms
  gc_time: fastest is a (flush-sync)
    a: ◼◼◼◼◼                0.26ms
    b: ◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼◼ 1.14ms

[Rich-Harris]

Not sure why we need a separate boolean and a try-catch wrapper. Simpler version: #15895

[Rich-Harris]

merged #15895, closing