[ric-oliv]

The macOS build job builds the Cocoa SDK from the sentry-cocoa submodule on every run. In the binlog of run 39921957359, that's 12.2 of the 23.7 minutes in the Build step, on one of the three MSBuild nodes. The other two run out of work by minute 10 and wait for the Cocoa bindings. The iOS device tests build it too.

version7 has cached it since #5746, and this PR brings the same steps to main:

• A cocoa-cache-key action keyed on the selected Xcode, build-sentry-cocoa.sh, sentry-cocoa.xcconfig and the submodule commit.
• Restore before the build, and save after a build that wrote the stamp, in the macOS leg and in the iOS device tests.
• Release branches skip the restore and build it from source, because it ships in the Sentry.Bindings.Cocoa package.

I left out the warm-up workflow, because pushes to main already run build.yml and save the cache for every PR. I also left out the pin-xcode action, which only the warm-up uses, and the verify-api change, which I'll send separately. The Cocoa steps match version7 line for line, so the next merge between the branches stays clean.

Measured against the median of 7 main runs from October 22 and 23:

	main	First run, cache miss	Reruns, cache hit
iOS Device Tests job	42.5 min	31.4	21.9
Build iOS Test App	6.1 to 12.6	6.7	1.7
macOS Build step	23.7	19.9	22.3 and 17.2

• On the reruns, both jobs restored the cache and skipped saving it.
• The iOS job gains the most, because its app build was waiting for the Cocoa SDK.
• The macOS Build step gains less than the 12 minutes the Cocoa build took, because the rest of the step keeps all three cores busy and the app samples become its tail. ci: build the app samples in their own job #5783 moves those samples into their own job, and with both changes the step took 6.6 minutes.
• I didn't compare the whole workflow, because the second rerun's time came from a linux-x64 runner that spent 28 minutes in Setup Environment.

#skip-changelog

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.13%. Comparing base (f080ba4) to head (09c2c55).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5781      +/-   ##
==========================================
+ Coverage   76.12%   76.13%   +0.01%     
==========================================
  Files         528      528              
  Lines       19579    19579              
  Branches     3829     3829              
==========================================
+ Hits        14904    14906       +2     
+ Misses       3792     3791       -1     
+ Partials      883      882       -1     

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[bitsandfoxes]

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