Cache mobile typechecks and overlap CI setup (#28192)

* ci: run mobile runtime test groups on separate runners

* ci: use a lightweight runner for the mobile result gate

* ci: distribute Bun tests across both mobile runners

* ci: reuse mobile compiler state without adding runner queues

* test: verify eviction of source variants in one cache bucket

* test: baseline existing serializer limits in the capacity capture

config/scripts/ci-dependency-download-cache.test.mjs

@@ -26,6 +26,7 @@ describe('CI dependency download caches', () => {
     const mobile = workflow('mobile').jobs.verify.steps.find((step) =>
       step.uses?.includes('install-node-dependencies')
     )
+    expect(mobile.with['cache-pnpm-store']).toBe('false')
     expect(mobile.with['cache-dependency-path'].trim().split('\n')).toEqual([
       'pnpm-lock.yaml',
       'mobile/pnpm-lock.yaml'

config/scripts/mobile-test-change-scope.test.mjs

@@ -91,11 +91,11 @@ it('overlaps both typechecks with tests and collects their failures before the s
   const waits = steps.filter((step) => step.wait !== undefined)
   expect(waits).toHaveLength(1)
   const [wait] = waits
-  expect(wait.wait).toEqual(['production-types', 'test-types'])
+  expect(wait.wait).toEqual(['production-types', 'test-types', 'ruby-tools'])
   expect(wait.if).toBeUndefined()
   expect(steps.indexOf(wait)).toBeGreaterThan(test)
   expect(steps.indexOf(wait)).toBeLessThan(summary)
-  for (const id of wait.wait) {
+  for (const id of ['production-types', 'test-types']) {
     const step = steps.find((candidate) => candidate.id === id)
     expect(step.background).toBe(true)
     expect(step['continue-on-error']).toBeUndefined()
@@ -104,4 +104,10 @@ it('overlaps both typechecks with tests and collects their failures before the s
     expect(steps.indexOf(step)).toBeLessThan(test)
     expect(step.run).toMatch(/^node /)
   }
+  const ruby = steps.find((step) => step.id === 'ruby-tools')
+  expect(ruby.uses).toBe('ruby/setup-ruby@v1')
+  expect(ruby.background).toBe(true)
+  expect(ruby.if).toBe("steps.ruby-scope.outputs.should_run != 'false'")
+  expect(ruby['continue-on-error']).toBeUndefined()
+  expect(steps.indexOf(ruby)).toBeLessThan(install)
 })

config/scripts/mobile-typecheck-cache.test.mjs

@@ -0,0 +1,41 @@
+import { readFileSync } from 'node:fs'
+import { expect, it } from 'vitest'
+import { parse } from 'yaml'
+
+it('reuses compiler state without skipping validation, and seeds it from main', () => {
+  const workflow = parse(readFileSync('.github/workflows/mobile.yml', 'utf8'))
+  for (const job of [workflow.jobs.verify, workflow.jobs['main-tests']]) {
+    expect(job.env.ORCA_MOBILE_TYPECHECK_CACHE_DIR).toBe(
+      '${{ github.workspace }}/mobile/.cache/typechecks'
+    )
+    const steps = job.steps
+    const cache = steps.find((step) => step.name === 'Cache mobile typecheck state')
+    expect(cache.uses).toBe('actions/cache@v5')
+    expect(cache.with.path).toBe('mobile/.cache/typechecks/*.tsbuildinfo')
+    expect(cache.with.key).toBe(`${cache.with['restore-keys']}${'${{ github.sha }}'}`)
+    for (const input of [
+      'runner.os',
+      'runner.arch',
+      'pnpm-lock.yaml',
+      'mobile/pnpm-lock.yaml',
+      'mobile/tsconfig*.json'
+    ]) {
+      expect(cache.with['restore-keys']).toContain(input)
+    }
+    const install = steps.findIndex((step) => step.name === 'Install dependencies')
+    const wait = steps.find((step) => step.wait)
+    for (const id of ['production-types', 'test-types']) {
+      const check = steps.find((step) => step.id === id)
+      expect(check.if).toBeUndefined()
+      expect(check.background).toBe(true)
+      expect(check['continue-on-error']).toBeUndefined()
+      expect(steps.indexOf(cache)).toBeGreaterThan(install)
+      expect(steps.indexOf(cache)).toBeLessThan(steps.indexOf(check))
+      expect(wait.wait).toContain(id)
+      expect(steps.indexOf(wait)).toBeGreaterThan(steps.indexOf(check))
+    }
+    expect(steps.find((step) => step.id === 'production-types').run).toContain(
+      '--incremental --tsBuildInfoFile "$ORCA_MOBILE_TYPECHECK_CACHE_DIR/production.tsbuildinfo"'
+    )
+  }
+})