Fix JSPI detection using runtime feature check by ivan-ottinger · Pull Request #2906 · Automattic/studio

ivan-ottinger · 2026-03-25T15:38:09Z

Related issues

Related to Disable Redis/memcached when JSPI is unavailable #2900
Related to STU-1366

How AI was used in this PR

Claude Code helped to investigate, reproduce, and fix the bug. I have reviewed the code, iterated over it and confirmed it works as expected.

Proposed Changes

Replace semver.gte(process.version, '24.0.0') with a runtime check for WebAssembly.promising to detect JSPI availability. The version check assumed Node 24+ has JSPI enabled by default, but it still requires the --experimental-wasm-jspi flag. This caused "Redis extension requires JSPI" errors when running CLI commands directly without the flag.
Remove unused semver imports from run-wp-cli-command.ts and wordpress-server-child.ts.

Testing Instructions

Build the CLI: npm run cli:build

Run without the JSPI flag (should succeed without Redis/memcached errors):

node apps/cli/dist/cli/main.js site set --wp=6.9.1 --path ~/Studio/<site>

Run with the JSPI flag (should succeed with Redis/memcached enabled):

node --experimental-wasm-jspi apps/cli/dist/cli/main.js site set --wp=6.9.1 --path ~/Studio/<site>

Try to reproduce the issue with the current trunk (the process should fail with an error):
```
node apps/cli/dist/cli/main.js site set --wp=6.9.1 --path ~/Studio/<site>
```

Pre-merge Checklist

Have you checked for TypeScript, React or other console errors?

Replace semver.gte(process.version, '24.0.0') with a runtime check for WebAssembly.promising to detect JSPI availability. The version check assumed Node 24+ has JSPI enabled by default, but it requires the --experimental-wasm-jspi flag. This caused "Redis extension requires JSPI" errors when running CLI commands directly without the flag. Extract the check into a shared isJspiAvailable helper in tools/common/lib/jspi.ts so there is a single source of truth.

…ection

fredrikekelund

Nice improvement. I think we should change some implementation details, but approving now to unblock you, @ivan-ottinger.

fredrikekelund · 2026-03-26T10:23:07Z

+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export const isJspiAvailable = typeof ( WebAssembly as any ).promising === 'function';


Suggested change

// eslint-disable-next-line @typescript-eslint/no-explicit-any

export const isJspiAvailable = typeof ( WebAssembly as any ).promising === 'function';

export const IS_JSPI_AVAILABLE = 'Suspending' in WebAssembly;

This is how they test it in Playground, apparently. Good to get rid of the type assertion, too.

Also, I'd rename the const in all caps.

fredrikekelund · 2026-03-26T10:37:41Z

I discovered an issue on this exact topic while smoke testing the new release: the bin wrapper script for the CLI didn't pass the --experimental-wasm-jspi flag to Node, which caused WP-CLI invocations to fail when the site wasn't started.

I took the opportunity of committing those changes to this PR, too.

* Fix JSPI detection using runtime feature check instead of Node version Replace semver.gte(process.version, '24.0.0') with a runtime check for WebAssembly.promising to detect JSPI availability. The version check assumed Node 24+ has JSPI enabled by default, but it requires the --experimental-wasm-jspi flag. This caused "Redis extension requires JSPI" errors when running CLI commands directly without the flag. Extract the check into a shared isJspiAvailable helper in tools/common/lib/jspi.ts so there is a single source of truth. * Remove unverified claim about JSPI proposal stage from comment * Fix linting * Address review suggestions * Pass `--experimental-wasm-jspi` to node in bin script --------- Co-authored-by: Fredrik Rombach Ekelund <fredrik.rombach.ekelund@automattic.com>

wpmobilebot · 2026-03-26T10:55:54Z

📊 Performance Test Results

Comparing 449d6e7 vs trunk

app-size

Metric	trunk	`449d6e7`	Diff	Change
App Size (Mac)	1247.24 MB	1247.24 MB	0.01 MB	⚪ 0.0%

site-editor

Metric	trunk	`449d6e7`	Diff	Change
load	1889 ms	1902 ms	+13 ms	⚪ 0.0%

site-startup

Metric	trunk	`449d6e7`	Diff	Change
siteCreation	8164 ms	8158 ms	6 ms	⚪ 0.0%
siteStartup	3928 ms	3938 ms	+10 ms	⚪ 0.0%

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)

ivan-ottinger · 2026-03-26T13:22:30Z

Nice! Thanks for bringing in the additional changes and merging the PR, Fredrik.

* [skip ci] Code freeze: Update translatable strings for 1.7.7 * [skip ci] Code freeze: Add draft release notes for 1.7.7 * Fix Prettier lint error in ipc-handlers import statement (#2893) * Update Studio CLI settings toggle copy and layout (#2855) * Update Studio CLI toggle copy and layout Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * Fix unit tests to follow UI change --------- Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Co-authored-by: Wojtek Naruniec <wojtek@naruniec.me> * Studio: Borders don't have correct colors in dark mode (#2885) * Add rule for buttons borders * Improve comment --------- Co-authored-by: Kateryna Kodonenko <kateryna@automattic.com> * [skip ci] Update translations * [skip ci] Bump version to 1.7.7-beta1 * Update CLI version * Preliminary release notes cleanup * Fix: CLI doesn't generate site thumbnails (#2850) * Consolidate thumbnail capture to shared CLI path Create a single thumbnail capture path through captureSiteThumbnail() that is used by both the desktop UI (loadThemeDetails) and CLI events subscriber. This eliminates duplication and uses pendingCaptures deduplication to prevent concurrent BrowserWindow creation when the same site is captured by multiple paths simultaneously. * remove comments * Use sequential util with deduplicateKey for thumbnail capture * Fix E2E copy-site test targeting wrong BrowserWindow The thumbnail capture feature creates hidden BrowserWindows for screenshots. The copy-site test used getAllWindows()[0] to send the IPC event, which could target the screenshot window instead of the main app window, causing the copy action to silently fail. Use getFocusedWindow() with a visible-window fallback instead. --------- Co-authored-by: katinthehatsite <katerynakodonenko@gmail.com> * Disable Redis/memcached when JSPI is unavailable (#2900) * Disable Redis and memcached PHP extensions when JSPI is unavailable These extensions require JSPI (JavaScript Promise Integration), which is only available in Node.js 24+. On Node <24, enabling them crashes the WordPress server at startup. This conditionally disables them when JSPI isn't available, matching the pattern in process-manager-daemon.ts. Also bumps the minimum engine version to >=24.0.0 since the production build strips asyncify binaries, making Node 24+ a de facto requirement. * Revert engine version bump to >=22.0.0 * Sort sites by sortOrder when loading from IPC (#2902) * Fix regressions around deleting preview sites (#2903) * Support deleting all preview sites from CLI and app * Update tests * Fix * Improve schemas and types * Tweak * Fix JSPI detection using runtime feature check (#2906) * Fix JSPI detection using runtime feature check instead of Node version Replace semver.gte(process.version, '24.0.0') with a runtime check for WebAssembly.promising to detect JSPI availability. The version check assumed Node 24+ has JSPI enabled by default, but it requires the --experimental-wasm-jspi flag. This caused "Redis extension requires JSPI" errors when running CLI commands directly without the flag. Extract the check into a shared isJspiAvailable helper in tools/common/lib/jspi.ts so there is a single source of truth. * Remove unverified claim about JSPI proposal stage from comment * Fix linting * Address review suggestions * Pass `--experimental-wasm-jspi` to node in bin script --------- Co-authored-by: Fredrik Rombach Ekelund <fredrik.rombach.ekelund@automattic.com> * [skip ci] Update translations * [skip ci] Bump version to 1.7.7-beta2 * Minuscule CLI README tweak (#2917) * Minuscule CLI README tweak * Fix tests * Address review comments * Rename `appdata-v1.json` to `appdata-v1.deprecated.json` (#2916) * Rename `appdata-v1.json` to `appdata-v1.deprecated.json` * Fix tests * Fix tests * Fix tests * Fix What's New current step icon color in dark mode (#2921) Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * Update release notes for 1.7.7 (#2905) * Update release notes for 1.7.7 * Address review suggestions * Ensure that language packs are bundled in `wp-files` (#2922) * Add phpMyAdmin to What's New dialog (#2920) * Add phpMyAdmin to What's New dialog Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> * Improve wording * Force What's New for next version * Update phpMyAdmin illustration with dot grid background Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> --------- Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com> Co-authored-by: Shaun Andrews <shaun@automattic.com> * Refactor and clean up site deletion logic in app (#2915) * Refactor site deletion in app * Nit fix * [skip ci] Bump version to 1.7.7-beta3 --------- Co-authored-by: Roberto Aranda <roberto.aranda@automattic.com> Co-authored-by: Shaun Andrews <shaun@automattic.com> Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Co-authored-by: Wojtek Naruniec <wojtek@naruniec.me> Co-authored-by: katinthehatsite <katerynakodonenko@gmail.com> Co-authored-by: Kateryna Kodonenko <kateryna@automattic.com> Co-authored-by: Fredrik Rombach Ekelund <fredrik.rombach.ekelund@automattic.com> Co-authored-by: Gergely Csécsey <gergely.csecsey@automattic.com> Co-authored-by: Ivan Ottinger <ivan.ottinger@automattic.com> Co-authored-by: Bernardo Cotrim <bmmcotrim@gmail.com> Co-authored-by: Fredrik Rombach Ekelund <fredrik@f26d.dev> Co-authored-by: Antonio Sejas <antonio.sejas@automattic.com> Co-authored-by: Wojtek Naruniec <wojtek.naruniec@automattic.com>

* [skip ci] Code freeze: Update translatable strings for 1.7.7 * [skip ci] Code freeze: Add draft release notes for 1.7.7 * Fix Prettier lint error in ipc-handlers import statement (#2893) * Update Studio CLI settings toggle copy and layout (#2855) * Update Studio CLI toggle copy and layout Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * Fix unit tests to follow UI change --------- Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Co-authored-by: Wojtek Naruniec <wojtek@naruniec.me> * Studio: Borders don't have correct colors in dark mode (#2885) * Add rule for buttons borders * Improve comment --------- Co-authored-by: Kateryna Kodonenko <kateryna@automattic.com> * [skip ci] Update translations * [skip ci] Bump version to 1.7.7-beta1 * Update CLI version * Preliminary release notes cleanup * Fix: CLI doesn't generate site thumbnails (#2850) * Consolidate thumbnail capture to shared CLI path Create a single thumbnail capture path through captureSiteThumbnail() that is used by both the desktop UI (loadThemeDetails) and CLI events subscriber. This eliminates duplication and uses pendingCaptures deduplication to prevent concurrent BrowserWindow creation when the same site is captured by multiple paths simultaneously. * remove comments * Use sequential util with deduplicateKey for thumbnail capture * Fix E2E copy-site test targeting wrong BrowserWindow The thumbnail capture feature creates hidden BrowserWindows for screenshots. The copy-site test used getAllWindows()[0] to send the IPC event, which could target the screenshot window instead of the main app window, causing the copy action to silently fail. Use getFocusedWindow() with a visible-window fallback instead. --------- Co-authored-by: katinthehatsite <katerynakodonenko@gmail.com> * Disable Redis/memcached when JSPI is unavailable (#2900) * Disable Redis and memcached PHP extensions when JSPI is unavailable These extensions require JSPI (JavaScript Promise Integration), which is only available in Node.js 24+. On Node <24, enabling them crashes the WordPress server at startup. This conditionally disables them when JSPI isn't available, matching the pattern in process-manager-daemon.ts. Also bumps the minimum engine version to >=24.0.0 since the production build strips asyncify binaries, making Node 24+ a de facto requirement. * Revert engine version bump to >=22.0.0 * Sort sites by sortOrder when loading from IPC (#2902) * Fix regressions around deleting preview sites (#2903) * Support deleting all preview sites from CLI and app * Update tests * Fix * Improve schemas and types * Tweak * Fix JSPI detection using runtime feature check (#2906) * Fix JSPI detection using runtime feature check instead of Node version Replace semver.gte(process.version, '24.0.0') with a runtime check for WebAssembly.promising to detect JSPI availability. The version check assumed Node 24+ has JSPI enabled by default, but it requires the --experimental-wasm-jspi flag. This caused "Redis extension requires JSPI" errors when running CLI commands directly without the flag. Extract the check into a shared isJspiAvailable helper in tools/common/lib/jspi.ts so there is a single source of truth. * Remove unverified claim about JSPI proposal stage from comment * Fix linting * Address review suggestions * Pass `--experimental-wasm-jspi` to node in bin script --------- Co-authored-by: Fredrik Rombach Ekelund <fredrik.rombach.ekelund@automattic.com> * [skip ci] Update translations * [skip ci] Bump version to 1.7.7-beta2 * Minuscule CLI README tweak (#2917) * Minuscule CLI README tweak * Fix tests * Address review comments * Rename `appdata-v1.json` to `appdata-v1.deprecated.json` (#2916) * Rename `appdata-v1.json` to `appdata-v1.deprecated.json` * Fix tests * Fix tests * Fix tests * Fix What's New current step icon color in dark mode (#2921) Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * Update release notes for 1.7.7 (#2905) * Update release notes for 1.7.7 * Address review suggestions * Ensure that language packs are bundled in `wp-files` (#2922) * Add phpMyAdmin to What's New dialog (#2920) * Add phpMyAdmin to What's New dialog Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> * Improve wording * Force What's New for next version * Update phpMyAdmin illustration with dot grid background Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> --------- Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com> Co-authored-by: Shaun Andrews <shaun@automattic.com> * Refactor and clean up site deletion logic in app (#2915) * Refactor site deletion in app * Nit fix * [skip ci] Bump version to 1.7.7-beta3 * Emit `deleted` site event when removing empty site (#2929) * Bump CLI version * [skip ci] Update translations * [skip ci] Bump version to 1.7.7 * [skip ci] Bump CLI version to 1.7.7 --------- Co-authored-by: Roberto Aranda <roberto.aranda@automattic.com> Co-authored-by: Shaun Andrews <shaun@automattic.com> Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com> Co-authored-by: Wojtek Naruniec <wojtek@naruniec.me> Co-authored-by: katinthehatsite <katerynakodonenko@gmail.com> Co-authored-by: Kateryna Kodonenko <kateryna@automattic.com> Co-authored-by: Fredrik Rombach Ekelund <fredrik.rombach.ekelund@automattic.com> Co-authored-by: Gergely Csécsey <gergely.csecsey@automattic.com> Co-authored-by: Ivan Ottinger <ivan.ottinger@automattic.com> Co-authored-by: Bernardo Cotrim <bmmcotrim@gmail.com> Co-authored-by: Fredrik Rombach Ekelund <fredrik@f26d.dev> Co-authored-by: Antonio Sejas <antonio.sejas@automattic.com> Co-authored-by: Wojtek Naruniec <wojtek.naruniec@automattic.com>

ivan-ottinger self-assigned this Mar 25, 2026

ivan-ottinger added 3 commits March 25, 2026 16:39

Remove unverified claim about JSPI proposal stage from comment

54f9104

Fix linting

31e27b2

Merge remote-tracking branch 'origin/trunk' into fix-jspi-runtime-det…

e84ed1d

…ection

ivan-ottinger marked this pull request as ready for review March 25, 2026 15:54

ivan-ottinger requested review from a team and fredrikekelund March 25, 2026 15:54

fredrikekelund approved these changes Mar 26, 2026

View reviewed changes

fredrikekelund added 2 commits March 26, 2026 11:35

Address review suggestions

b6077ad

Pass --experimental-wasm-jspi to node in bin script

449d6e7

fredrikekelund merged commit 2198b21 into trunk Mar 26, 2026
8 of 10 checks passed

fredrikekelund deleted the fix-jspi-runtime-detection branch March 26, 2026 10:50

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Fix JSPI detection using runtime feature check - #2906

Fix JSPI detection using runtime feature check#2906
fredrikekelund merged 6 commits into
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ivan-ottinger commented Mar 25, 2026 •

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		// eslint-disable-next-line @typescript-eslint/no-explicit-any
		export const isJspiAvailable = typeof ( WebAssembly as any ).promising === 'function';

	// eslint-disable-next-line @typescript-eslint/no-explicit-any
	export const isJspiAvailable = typeof ( WebAssembly as any ).promising === 'function';
	export const IS_JSPI_AVAILABLE = 'Suspending' in WebAssembly;

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Related issues

How AI was used in this PR

Proposed Changes

Testing Instructions

Pre-merge Checklist

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wpmobilebot commented Mar 26, 2026

📊 Performance Test Results

app-size

site-editor

site-startup

ivan-ottinger commented Mar 26, 2026

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3 participants

ivan-ottinger commented Mar 25, 2026 •

edited

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