feat(descriptors): minimize blocking the UI

[judofyr]

Description

This adds a "pauser" into the descriptor converter which avoids blocking the UI by scheduling idle callbacks. See the comment in the code for justification and potential follow-up work.

What to review

This PR.

Testing

N/A.

Notes for release

N/A. Internal only at the moment.

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Project	Deployment	Preview	Comments	Updated (UTC)
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[judofyr]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• feat(descriptors): minimize blocking the UI #11310 👈 (View in Graphite)
• refactor(descriptors): make descriptor converter async #11309
• feat(schema): de-dupe re-used fields in the descriptor #11240
• refactor(schema): remove unused options to DescriptorConverter #11239
• feat(schema): cache generated field/type objects #11236
• feat(cli): add command for visualizing schema bloat #11224
• fix(cli): load config properly in sanity schema validate #11223
• main

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[github-actions]

🧪 E2E Preview environment

🔑 Environment Variables for Local Testing

This is the preview URL for the E2E tests: https://e2e-studio-iuwlos0ff.sanity.dev

To run the E2E tests locally, you can use the following environment variables, then run pnpm test:e2e --ui to open the Playwright test runner.

💬 Remember to build the project first with pnpm build:e2e.

  SANITY_E2E_PROJECT_ID=ittbm412
  SANITY_E2E_BASE_URL=https://e2e-studio-iuwlos0ff.sanity.dev
  SANITY_E2E_DATASET="update depending the project you want to test (pr-11310-chromium-19764655675 || pr-11310-firefox-19764655675 )"
  SANITY_E2E_DATASET_CHROMIUM=pr-11310-chromium-19764655675
  SANITY_E2E_DATASET_FIREFOX=pr-11310-firefox-19764655675

[github-actions]

📊 Playwright Test Report

Download Full E2E Report

This report contains test results, including videos of failing tests.

[github-actions]

⚡️ Editor Performance Report

Updated Fri, 28 Nov 2025 13:22:49 GMT

Benchmark	reference latency of sanity@latest	experiment latency of this branch	Δ (%) latency difference
article (title)	28.6 efps (35ms)	27.0 efps (37ms)	+2ms (+5.7%)	✅
article (body)	38.8 efps (26ms)	37.2 efps (27ms)	+1ms (+4.3%)	✅
article (string inside object)	29.9 efps (34ms)	28.2 efps (36ms)	+2ms (+6.0%)	✅
article (string inside array)	24.4 efps (41ms)	24.4 efps (41ms)	+0ms (-/-%)	✅
recipe (name)	52.6 efps (19ms)	50.0 efps (20ms)	+1ms (+5.3%)	✅
recipe (description)	64.5 efps (16ms)	69.0 efps (15ms)	-1ms (-/-%)	✅
recipe (instructions)	99.9+ efps (7ms)	99.9+ efps (7ms)	-0ms (-/-%)	✅
singleString (stringField)	71.4 efps (14ms)	66.7 efps (15ms)	+1ms (-/-%)	✅
synthetic (title)	17.2 efps (58ms)	18.2 efps (55ms)	-3ms (-5.2%)	✅
synthetic (string inside object)	17.2 efps (58ms)	17.9 efps (56ms)	-2ms (-3.4%)	✅

efps — editor "frames per second". The number of updates assumed to be possible within a second.

Derived from input latency. efps = 1000 / input_latency

Detailed information

🏠 Reference result

The performance result of sanity@latest

Benchmark	latency	p75	p90	p99	blocking time	test duration
article (title)	35ms	38ms	41ms	98ms	26ms	9.9s
article (body)	26ms	31ms	67ms	239ms	281ms	6.3s
article (string inside object)	34ms	38ms	40ms	130ms	41ms	6.0s
article (string inside array)	41ms	45ms	50ms	138ms	40ms	6.2s
recipe (name)	19ms	21ms	24ms	44ms	0ms	7.7s
recipe (description)	16ms	18ms	24ms	36ms	0ms	4.1s
recipe (instructions)	7ms	10ms	12ms	57ms	11ms	3.1s
singleString (stringField)	14ms	16ms	20ms	37ms	0ms	6.0s
synthetic (title)	58ms	62ms	65ms	175ms	375ms	14.8s
synthetic (string inside object)	58ms	61ms	82ms	159ms	309ms	7.5s

🧪 Experiment result

The performance result of this branch

Benchmark	latency	p75	p90	p99	blocking time	test duration
article (title)	37ms	41ms	71ms	128ms	52ms	10.2s
article (body)	27ms	31ms	82ms	198ms	192ms	6.2s
article (string inside object)	36ms	40ms	44ms	175ms	106ms	5.8s
article (string inside array)	41ms	44ms	69ms	124ms	57ms	6.3s
recipe (name)	20ms	22ms	23ms	50ms	1ms	7.5s
recipe (description)	15ms	18ms	24ms	52ms	0ms	4.2s
recipe (instructions)	7ms	10ms	11ms	15ms	0ms	3.1s
singleString (stringField)	15ms	17ms	20ms	39ms	0ms	6.6s
synthetic (title)	55ms	57ms	66ms	163ms	267ms	15.9s
synthetic (string inside object)	56ms	57ms	59ms	134ms	189ms	7.2s

📚 Glossary

column definitions

• benchmark — the name of the test, e.g. "article", followed by the label of the field being measured, e.g. "(title)".
• latency — the time between when a key was pressed and when it was rendered. derived from a set of samples. the median (p50) is shown to show the most common latency.
• p75 — the 75th percentile of the input latency in the test run. 75% of the sampled inputs in this benchmark were processed faster than this value. this provides insight into the upper range of typical performance.
• p90 — the 90th percentile of the input latency in the test run. 90% of the sampled inputs were faster than this. this metric helps identify slower interactions that occurred less frequently during the benchmark.
• p99 — the 99th percentile of the input latency in the test run. only 1% of sampled inputs were slower than this. this represents the worst-case scenarios encountered during the benchmark, useful for identifying potential performance outliers.
• blocking time — the total time during which the main thread was blocked, preventing user input and UI updates. this metric helps identify performance bottlenecks that may cause the interface to feel unresponsive.
• test duration — how long the test run took to complete.

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	44.75%	63947 / 142892
🔵	Statements	44.75%	63947 / 142892
🔵	Functions	48.37%	3416 / 7061
🔵	Branches	79.42%	13036 / 16414

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
packages/@sanity/schema/src/descriptors/convert.ts	93.45%	88.81%	96.29%	93.45%	105, 423-424, 516-517, 525-533, 553-554, 567-574, 630-631, 645-646, 664, 674, 684, 692, 704, 718, 726, 736, 742, 744, 770-771
packages/@sanity/schema/src/descriptors/scheduler.ts	21.73%	80%	75%	21.73%	16-84
packages/sanity/src/core/config/uploadSchema.ts	38.96%	41.66%	100%	38.96%	21-22, 76-81, 87-135

Generated in workflow #46668 for commit 24cc74c by the Vitest Coverage Report Action

[judofyr]

I've now slightly tweaked it:

• Adding a "scheduler" interface so that outside of the browser (i.e. sanity schema validate) we don't unnecessarily use idle callbacks.
• Add more higher level methods for "doing work" instead of "pausing".
• Avoid pausing when it's been too short since the last pause.
• Fixed a bug with the duration recording.