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.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Preview	Comments	Updated (UTC)
page-building-studio	Ready	Preview	Comment	Dec 1, 2025 2:54pm
test-studio	Ready	Preview	Comment	Dec 1, 2025 2:54pm

3 Skipped Deployments

Project	Deployment	Preview	Comments	Updated (UTC)
e2e-studio	Ignored			Dec 1, 2025 2:54pm
studio-workshop	Ignored	Preview		Dec 1, 2025 2:54pm
test-next-studio	Ignored			Dec 1, 2025 2:54pm

[judofyr]

• 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

This stack of pull requests is managed by Graphite. Learn more about stacking.

[github-actions]

🧪 E2E Preview environment

🔑 Environment Variables for Local Testing

This is the preview URL for the E2E tests: https://e2e-studio-1ga9prpa2.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-1ga9prpa2.sanity.dev
  SANITY_E2E_DATASET="update depending the project you want to test (pr-11310-chromium-19826878628 || pr-11310-firefox-19826878628 )"
  SANITY_E2E_DATASET_CHROMIUM=pr-11310-chromium-19826878628
  SANITY_E2E_DATASET_FIREFOX=pr-11310-firefox-19826878628

[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 Mon, 01 Dec 2025 15:08:27 GMT

Benchmark	reference latency of sanity@latest	experiment latency of this branch	Δ (%) latency difference
article (title)	23.8 efps (42ms)	21.1 efps (48ms)	+6ms (+13.1%)	✅
article (body)	24.1 efps (42ms)	29.0 efps (35ms)	-7ms (-17.0%)	✅
article (string inside object)	26.0 efps (39ms)	22.2 efps (45ms)	+7ms (+16.9%)	✅
article (string inside array)	21.7 efps (46ms)	19.2 efps (52ms)	+6ms (+13.0%)	✅
recipe (name)	41.7 efps (24ms)	39.2 efps (26ms)	+2ms (+6.3%)	✅
recipe (description)	55.6 efps (18ms)	55.6 efps (18ms)	+0ms (-/-%)	✅
recipe (instructions)	99.9+ efps (7ms)	90.9 efps (11ms)	+4ms (-/-%)	✅
singleString (stringField)	50.0 efps (20ms)	52.6 efps (19ms)	-1ms (-5.0%)	✅
synthetic (title)	15.9 efps (63ms)	15.7 efps (64ms)	+1ms (+0.8%)	✅
synthetic (string inside object)	16.4 efps (61ms)	15.4 efps (65ms)	+4ms (+6.6%)	✅

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)	42ms	49ms	58ms	105ms	30ms	10.5s
article (body)	42ms	66ms	106ms	159ms	242ms	7.6s
article (string inside object)	39ms	41ms	55ms	117ms	0ms	6.4s
article (string inside array)	46ms	54ms	87ms	121ms	55ms	6.9s
recipe (name)	24ms	27ms	30ms	46ms	0ms	7.1s
recipe (description)	18ms	21ms	23ms	27ms	0ms	4.3s
recipe (instructions)	7ms	13ms	15ms	44ms	0ms	3.4s
singleString (stringField)	20ms	22ms	24ms	48ms	0ms	6.6s
synthetic (title)	63ms	65ms	72ms	204ms	432ms	16.1s
synthetic (string inside object)	61ms	68ms	118ms	277ms	637ms	8.2s

🧪 Experiment result

The performance result of this branch

Benchmark	latency	p75	p90	p99	blocking time	test duration
article (title)	48ms	54ms	87ms	139ms	60ms	10.3s
article (body)	35ms	40ms	93ms	175ms	161ms	7.3s
article (string inside object)	45ms	52ms	67ms	127ms	31ms	6.8s
article (string inside array)	52ms	57ms	67ms	159ms	52ms	7.1s
recipe (name)	26ms	31ms	44ms	102ms	9ms	7.4s
recipe (description)	18ms	22ms	27ms	40ms	0ms	4.4s
recipe (instructions)	11ms	12ms	15ms	28ms	0ms	3.3s
singleString (stringField)	19ms	22ms	30ms	46ms	0ms	6.4s
synthetic (title)	64ms	68ms	119ms	175ms	603ms	14.5s
synthetic (string inside object)	65ms	69ms	121ms	138ms	435ms	8.1s

📚 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	44.46%	64004 / 143945
🔵	Statements	44.46%	64004 / 143945
🔵	Functions	48.35%	3416 / 7065
🔵	Branches	79.28%	13000 / 16397

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 #46803 for commit 316b1e2 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.

[dcilke]

Personally, I think having just the scheduler as an option is a cleaner API

The base branch was changed.