Road to 0.83

[Saadnajmi]

Tracking issue for the merge-up from upstream 0.83-stable (facebook/react-native).
Work is happening on the 0.83-merge branch.

• Merge chore: merge up to 0.83-stable branch #2824 — Initial 0.83-stable merge into 0.83-merge branch
• CI for merge branches — Add *-merge to workflow triggers (microsoft-pr.yml, test-all.yml, publish-bumped-packages.yml, codeql-analysis.yml) so CI runs on 0.83-merge
• ** Verify focus changes ** - Added upstream in core, but we need to make sure macOS didn't regress
• Hermes V1 support — From 0.83+, Hermes is published separately (com/facebook/hermes/hermes-ios) with its own versioning. Add version.properties, update hermes-engine.podspec and hermes-utils.rb to support RCT_HERMES_V1_ENABLED env var and new Maven coordinates, with findMatchingHermesVersion() fallback
• RCTUIKit Swift module — RCTUIKit.h can't be imported from Swift (needed by RCTSwiftUIContainerView.swift). Already broken out into its own module on main, needs rebase into 0.83-merge
• Codegen package name constant — react-native.config.js:192 hardcodes 'react-native-macos' instead of using the REACT_NATIVE constant from constants.js. Follow up on core
• Audit upstream breaking changes — Review 0.83 release notes for breaking changes and update macOS-specific APIs as needed
• RNTester validation — Verify RNTester builds and runs on macOS, pod install works (both legacy and V1 Hermes)
• react-native-test-app integration — Test RNTA compatibility with 0.83 changes
• Merge 0.83-merge → main — Final review, all CI green, merge

[tvinhas]

I spent time validating 0.83-merge end-to-end (RNTester pod install cycle on macOS) and opened a batch of PRs against the unchecked items in this issue. Filing them together so the scope is visible at a glance.

PRs

• fix(codegen): use REACT_NATIVE constant for npmPackageName #2956 — fix(codegen): use REACT_NATIVE constant for npmPackageName
  Closes "Codegen package name constant".

• fix(hermes): pick static_h vs main branch by RCT_HERMES_V1_ENABLED in hermes-utils.rb #2957 — fix(hermes): pick static_h vs main branch by RCT_HERMES_V1_ENABLED in hermes-utils.rb
  Companion to your draft fix(ci): align Resolve Hermes with HermesV1 / hermesvm.xcframework #2952. Mirrors the JS-side static_h branch selection onto the Ruby hermes_commit_at_merge_base path, so the from-source fallback uses V1 Hermes source when RCT_HERMES_V1_ENABLED=1. With fix(ci): align Resolve Hermes with HermesV1 / hermesvm.xcframework #2952 + fix(hermes): pick static_h vs main branch by RCT_HERMES_V1_ENABLED in hermes-utils.rb #2957
  landed, the V1 producer (CI) and consumer (podspec from-source) paths are aligned.

• fix(macos): expose React-RCTUIKit module to RCTSwiftUI Swift consumers #2958 — fix(macos): expose React-RCTUIKit module to RCTSwiftUI Swift consumers
  Closes "RCTUIKit Swift module". The module-ification from refactor: move RCTUIKit into a separate module #2847 was already in 0.83-merge via the upstream pull; what was missing was the consumer-side wiring on RCTSwiftUI — s.dependency "React-RCTUIKit" in the podspec +
  import React_RCTUIKit in the Swift, dropping the now-redundant RCTPlatformView / RCTUIColor Swift typealiases.

• fix(macos): three Fabric focus regressions (blur, sendAccessibilityEvent, VirtualView) #2959 — fix(macos): three Fabric focus regressions (blur, sendAccessibilityEvent, VirtualView)
  Closes "Verify focus changes" for three concrete regressions:

  1. RCTViewComponentView.mm blur() was calling [[self window] resignFirstResponder] — silent no-op on NSWindow. Fixed to makeFirstResponder:nil, mirroring the working pattern in RCTTextInputComponentView.mm.
  2. RCTMountingManager.mm Fabric sendAccessibilityEvent("focus") had no #else branch on macOS — AccessibilityInfo.setAccessibilityFocus was silently dropped. Added the macOS path mirroring RCTAccessibilityManager.mm's
     old-arch implementation.
  3. RCTVirtualViewComponentView.mm had no macOS hook equivalent to iOS's focusItemsInRect: for keyboard nav reaching a hidden virtual view. Partial fix: acceptsFirstResponder + accessibilityHitTest: unhide on entry. Fully
     solving Tab-into-fully-hidden requires changing the hide strategy from self.hidden = YES to something that keeps the view in the responder chain — flagged as a follow-up.

• fix(rn-tester): restore RNTesterPods.xcodeproj/project.pbxproj on 0.83-merge #2960 — fix(rn-tester): restore RNTesterPods.xcodeproj/project.pbxproj on 0.83-merge
  Unblocks "RNTester validation". pod install on 0.83-merge currently fails with [!] The plist file at path .../project.pbxproj doesn't exist before reaching any install step. The file is tracked on main (blob 90e6c295…)
  but absent on 0.83-merge — most likely dropped during the upstream merge and then held out by the existing .gitignore rule on /packages/rn-tester/**/*.xcodeproj. PR restores it via force-add; nothing else changes. After this, pod install resolves 86 deps / 85 installed.

  Item that may already be done

"Audit upstream breaking changes" — a diff sweep of v0.82.0...v0.83.0 upstream cross-referenced with the current 0.83-merge tree suggests this is already absorbed:

• GenerateModuleCpp.js removal + tests + snapshots: no callsites remain in the fork.
• ReactFabricHostComponent.js consolidated into ReactFabricPublicInstance.js: standalone file already gone.
• AppDelegate header reorg + devMenuConfiguration parameter threading: RCTReactNativeFactory.h:120 has the property; RCTRootViewFactory.{h,mm} carries the new viewWithModuleName:...:devMenuConfiguration: signature;
  RCT_REMOVE_LEGACY_ARCH guards are in place across RCTAppSetupUtils.mm and RCTReactNativeFactory.mm.
• React 19.1 → 19.2 peer: packages/react-native/package.json already at "react": "^19.2.0".

The 8 JS files that carry [macOS] markers AND were also modified upstream (ViewNativeComponent.js, ScrollView.js, TextInput.js, AccessibilityInfo.js, ImageInjection.js, others) still warrant per-file three-way-merge spot
checks — happy to take that as a follow-up if useful.

Validation methodology

For each fix:

• syntax/parse of the touched file (ruby -c, node --check) clean
• pod install against packages/rn-tester on 0.83-merge (after fix(rn-tester): restore RNTesterPods.xcodeproj/project.pbxproj on 0.83-merge #2960's pbxproj restore lands locally) resolves cleanly with the new dependency edges
• new code paths cite an existing known-working pattern in the same codebase, per PR

xcodebuild of the RNTester-macOS scheme is the natural next validation step once #2960 (or an equivalent) lands.

Let me know if any of these want restructuring (split / narrowed scope / different framing) — happy to adapt.

[tvinhas]

Quick follow-up on Hermes V1 support — completed end-to-end validation locally.

Result: RCT_HERMES_V1_ENABLED=1 works on 0.83-merge for macOS through the full build pipeline.

• pod install resolves: Installing hermes-engine 250829098.0.2 (was 0.14.0) — V1 Maven artifact downloads cleanly
• Podfile.lock records hermes-engine (250829098.0.2) + hermes-engine/Pre-built (250829098.0.2)
• xcodebuild -scheme RNTester-macOS -configuration Debug completes with ** BUILD SUCCEEDED **
• The produced RNTester-macOS.app/Contents/Frameworks/hermesvm.framework is the V1-named binary (not legacy hermes.framework)

Validated with #2957 (Ruby static_h branch fix) + #2952 (your JS-side companion, still draft) + #2961 (fmt FMT_USE_CONSTEVAL=0 — required to get past the fmt compile on Xcode 26.x) + #2962 (RCTViewComponentView macOS guards — required
to get past the React-RCTFabric compile).

The remaining "from-source fallback" path (RCT_BUILD_HERMES_FROM_SOURCE=true with no Maven artifact) wasn't exercised since the Maven release was available. With #2952 + #2957 the branch logic is correct; the from-source build should
follow.

Suggest ticking "Hermes V1 support" on this issue once #2952 and #2957 land. The V1 plumbing in 0.83-merge is otherwise complete.