fix: Improve Big Sur browser detection performance

[chrisbreiding]

• Closes Detection of browsers take a long time on Mac OS Big Sur #17773

User facing changelog

• Projects will now open much faster on MacOS Big Sur with improved browser detection performance.

Additional details

The root of the issue is this bug in Electron, which causes spawning child processes to take 300-1000ms instead of the usual <30ms when using MacOS Big Sur and Electron 12+. We spawn a child process for each binary of each browser, plus potential fallback lookups if any of the standard ones fail. This causes the browser detection on Big Sur to take upwards of 10 seconds.

We considered using the Electron patch in that issue, but it's not a perfect solution (it was reverted in libuv due to failing tests), and would require us to build Electron ourselves, which is a large amount of work and responsibility.

As a workaround, we spawn a single child process (only incurring the performance penalty once instead of N+ times), and use it to call into our browser detection code from the user's Node.js. Since it's outside Electron, it doesn't suffer from the same bug and performs quickly. This reduces the time taken for browser detection from ~10s to ~1s.

How has the user experience changed?

Users on Big Sur will see projects open much quicker.

PR Tasks

• Have tests been added/updated?
• Has the original issue or this PR been tagged with a release in ZenHub?
• N/A Has a PR for user-facing changes been opened in cypress-documentation?
• N/A Have API changes been updated in the type definitions?
• N/A Have new configuration options been added to the cypress.schema.json?

[cypress-bot]

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[bahmutov]

👏 👏 👏

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[cypress]

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Test summary

18458 • 0 • 214 • 7 • 8

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Run details

Project	cypress
Status	Passed
Commit	891f2ec
Started	Aug 19, 2021 6:20 PM
Ended	Aug 19, 2021 6:31 PM
Duration	10:47 💡
OS	Linux Debian - 10.9
Browser	Multiple

View run in Cypress Dashboard ➡️

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Flakiness

	commands/net_stubbing_spec.ts		1
1	network stubbing > intercepting request > can intercept utf-8 request bodies without crashing
	commands/xhr_spec.js		2
1	... > can alias a route without stubbing it
2	src/cy/commands/xhr > abort > aborts xhrs currently in flight
	dom/visibility_spec.ts		1
1	... > has `opacity: 0`
	cypress/proxy-logging-spec.ts		1
1	Proxy Logging > request logging > fetch log shows resource type, url, method, and status code and has expected snapshots and consoleProps
This comment includes only the first 5 flaky tests. See all 8 flaky tests in the Cypress Dashboard.

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[JessicaSachs]

Nice. Thank you!

[flotwig]

We do what we can because we must. LGTM

[flotwig]

BTW, was not able to test this on an actual Big Sur install as part of my review, my VM is stuck on Catalina.

[flotwig]

An upstream fix is coming: electron/electron#26143 (comment)