rnw-integration

---
name: rnw-integration
description: 'Automate React Native Windows integration with upstream React Native nightly versions. Use when: upgrading RNW to a newer React Native nightly, finding target nightly versions, preparing integration PRs, updating package dependencies.'
argument-hint: 'Describe the integration task (e.g., "find next nightly version")'
---

# RNW Integration Automation

Automates the process of integrating React Native Windows with upstream React Native nightly builds.

## When to Use

- Finding the target React Native nightly version for integration
- Upgrading RNW dependencies to a new React Native nightly
- Preparing integration pull requests
- Validating nightly version availability on npm

## Procedure

### Step 1: Get Current React Native Version

Extract the current `react-native` version from `vnext/package.json`:

```powershell
$packageJson = Get-Content -Path "vnext/package.json" | ConvertFrom-Json
$currentVersion = $packageJson.devDependencies.'react-native'
Write-Host "Current version: $currentVersion"
```

Expected format: `0.XX.0-nightly-YYYYMMDD-<commit-hash>`

After completing this step, confirm: **Step 1 completed successfully.**

### Step 2: Parse the Current Version Date

Extract the date from the nightly version string:

```powershell
# Parse version like: 0.84.0-nightly-20260107-58bc6c3e3
$versionMatch = $currentVersion -match 'nightly-(\d{8})'
$currentDate = [DateTime]::ParseExact($matches[1], 'yyyyMMdd', $null)
Write-Host "Current nightly date: $($currentDate.ToString('yyyy-MM-dd'))"
```

After completing this step, confirm: **Step 2 completed successfully.**

### Step 3: Calculate Target Date (+7 days)

```powershell
$targetDate = $currentDate.AddDays(7)
$targetDateStr = $targetDate.ToString('yyyyMMdd')
Write-Host "Target date (+7 days): $($targetDate.ToString('yyyy-MM-dd'))"
```

After completing this step, confirm: **Step 3 completed successfully.**

### Step 4: Find Nightly Version on npm

Query npm for available nightly versions around the target date:

```powershell
# Get all nightly versions for the target month
$yearMonth = $targetDate.ToString('yyyyMM')
$nightlyVersions = npm view react-native versions --json 2>$null | 
    ConvertFrom-Json | 
    Where-Object { $_ -like "*nightly-$yearMonth*" }

# Find exact match or next available
$targetVersion = $nightlyVersions | Where-Object { $_ -like "*nightly-$targetDateStr*" } | Select-Object -First 1

if (-not $targetVersion) {
    Write-Host "No nightly for $targetDateStr, finding next available..."
    $targetVersion = $nightlyVersions | Where-Object { 
        $_ -match 'nightly-(\d{8})' -and [int]$matches[1] -gt [int]$targetDateStr 
    } | Select-Object -First 1
}

Write-Host "Target nightly version: $targetVersion"
```

After completing this step, confirm: **Step 4 completed successfully.**

### Step 5: Output Summary

```powershell
Write-Host ""
Write-Host "=== Integration Summary ==="
Write-Host "Current Version: $currentVersion"
Write-Host "Current Date:    $($currentDate.ToString('yyyy-MM-dd'))"
Write-Host "Target Date:     $($targetDate.ToString('yyyy-MM-dd'))"
Write-Host "Target Version:  $targetVersion"
```

After completing this step, confirm: **Step 5 completed successfully.**

### Step 6: Run Integration Script

Run the integration script with the target nightly version to update all dependencies:

```powershell
yarn integrate-rn $targetVersion
```

This command updates all `react-native` and `@react-native/*` package references across the monorepo to the target nightly version.

After completing this step, confirm: **Step 6 completed successfully.**

### Step 7: Search and Update Remaining package.json Files

After running the integration script, search all `package.json` files for any remaining references to the previous nightly version and update them:

```powershell
# Find all package.json files containing the previous nightly version
$packageFiles = Get-ChildItem -Path . -Filter "package.json" -Recurse -File | 
    Where-Object { $_.FullName -notlike "*node_modules*" }

$updatedFiles = @()

foreach ($file in $packageFiles) {
    $content = Get-Content -Path $file.FullName -Raw
    if ($content -like "*$currentVersion*") {
        Write-Host "Found previous version in: $($file.FullName)"
        $newContent = $content -replace [regex]::Escape($currentVersion), $targetVersion
        Set-Content -Path $file.FullName -Value $newContent -NoNewline
        $updatedFiles += $file.FullName
    }
}

Write-Host ""
Write-Host "=== Updated $($updatedFiles.Count) package.json files ==="
$updatedFiles | ForEach-Object { Write-Host "  - $_" }
```

This ensures all references to the previous nightly version are updated, including:
- `dependencies`
- `devDependencies`
- `peerDependencies`
- `resolutions`

After completing this step, confirm: **Step 7 completed successfully.**

### Step 8: Clean node_modules and Reinstall Dependencies

After updating all package.json files, remove all `node_modules` directories across the repo and perform a fresh install to ensure the dependency tree is consistent with the new versions:

```powershell
# Delete all node_modules directories (excluding .git)
Get-ChildItem -Path . -Directory -Filter "node_modules" -Recurse |
    Where-Object { $_.FullName -notlike "*.git*" } |
    ForEach-Object {
        Write-Host "Removing: $($_.FullName)"
        Remove-Item -Recurse -Force $_.FullName
    }

Write-Host "All node_modules directories removed."
```

Then run a fresh install at the root of the repo:

```powershell
yarn install
```

If `yarn install` fails (e.g., due to peer dependency mismatches or build script errors), diagnose and fix the issue:
- **Peer dependency warnings**: These are typically non-blocking in Yarn 4. Check if the install actually completed.
- **Build script failures**: Check the build log path shown in the error output. Common issues include missing type declarations or renamed modules — fix the source files causing the build error and re-run `yarn install`.
- **Resolution conflicts**: If a resolution in the root `package.json` still points to an old version, update it to the target nightly version.

After completing this step, confirm: **Step 8 completed successfully.**

### Step 9: Upgrade Platform Overrides

Run the override upgrade tool to resolve conflicts in platform-specific override files:

```powershell
npx react-native-platform-override upgrade
```

This interactive tool helps resolve conflicts between upstream React Native changes and RNW platform overrides. It will:
- Show files with merge conflicts
- Allow you to accept upstream changes, keep local changes, or manually merge
- Update the overrides.json manifest files

After completing the upgrade, verify the overrides are valid:

```powershell
yarn validate-overrides
```

After completing this step, confirm: **Step 9 completed successfully.**

### Step 10: Commit All Changes

After completing all integration steps, commit the changes:

```powershell
git add -A
git commit -m "Integrate RN $targetVersion"
```

This creates a single commit with all the integration changes including:
- Updated package.json dependencies
- Override file upgrades
- Any auto-fixed lint issues

After completing this step, confirm: **Step 10 completed successfully.**

### Step 11: Update Failing Overrides from Upstream

Run `yarn validate-overrides` to identify which folders need to be replaced with upstream versions, then download and replace them:

```powershell
# Extract commit hash from target version (last 8 characters after final hyphen)
# Example: 0.85.0-nightly-20260114-f15985f4f -> f15985f4f
$commitHash = ($targetVersion -split '-')[-1]
Write-Host "Commit hash: $commitHash"

# Run validate-overrides and capture failing paths
$validateOutput = yarn validate-overrides 2>&1
$failingPaths = $validateOutput | Where-Object { $_ -match '^ - ' } | ForEach-Object { $_.Trim(' -') }

if ($failingPaths.Count -eq 0) {
    Write-Host "No failing overrides to update"
    return
}

Write-Host "Found $($failingPaths.Count) failing override paths to update"

# Create temp directory (outside git tracking)
$tempDir = "$env:TEMP\rn-upstream-$commitHash"
if (Test-Path $tempDir) { Remove-Item -Recurse -Force $tempDir }
New-Item -ItemType Directory -Path $tempDir | Out-Null

# Download react-native repo at the specific commit
Write-Host "Downloading react-native at commit $commitHash..."
git clone --depth 1 --filter=blob:none --sparse https://github.com/facebook/react-native.git $tempDir
Push-Location $tempDir
git sparse-checkout set packages/rn-tester
git fetch --unshallow
git checkout $commitHash
Pop-Location

# Replace each failing path with upstream version
foreach ($path in $failingPaths) {
    # Convert absolute path to relative
    $relativePath = $path -replace [regex]::Escape((Get-Location).Path + '\'), ''
    
    # Map RNW paths to upstream rn-tester paths
    $upstreamPath = $null
    
    if ($relativePath -like "packages\@react-native\tester\*") {
        # packages\@react-native\tester\X -> packages\rn-tester\X
        $subPath = $relativePath -replace '^packages\\@react-native\\tester\\', ''
        $upstreamPath = "$tempDir\packages\rn-tester\$subPath"
    }
    elseif ($relativePath -like "vnext\ReactCopies\*") {
        # vnext\ReactCopies\X -> packages\rn-tester\X
        $subPath = $relativePath -replace '^vnext\\ReactCopies\\', ''
        $upstreamPath = "$tempDir\packages\rn-tester\$subPath"
    }
    
    if ($upstreamPath -and (Test-Path $upstreamPath)) {
        Write-Host "Replacing $relativePath with upstream version..."
        Remove-Item -Recurse -Force $relativePath
        Copy-Item -Recurse -Force $upstreamPath $relativePath
    } else {
        Write-Host "WARNING: Could not find upstream path for $relativePath"
    }
}

# Cleanup temp directory
Remove-Item -Recurse -Force $tempDir
Write-Host "Overrides updated from upstream commit $commitHash"
```

Verify the overrides are valid after the update:

```powershell
yarn validate-overrides
```

After completing this step, confirm: **Step 11 completed successfully.**

### Step 12: Resolve Merge Conflicts (Human-in-the-Loop)

After Steps 9-11, some override files may still contain merge conflict markers (`<<<<<<<`, `=======`, `>>>>>>>`). This step resolves them safely with human approval for each hunk.

**NON-NEGOTIABLE CONSTRAINTS:**
- Conflicts are handled hunk-by-hunk (each `<<<<<<<` ... `=======` ... `>>>>>>>` region is one hunk)
- HUMAN-IN-THE-LOOP: Do NOT apply any change automatically — ask for explicit approval for EACH hunk
- Safety exceptions:
  - Some `>>>>>>>` markers are intentional (e.g., E2E `react-native-platform-override` files) — do not "fix" those
  - Leave conflicts in `flowconfig.windows.conflict` untouched

#### Phase 1 — Build RNW Conflict-Resolution Knowledge Base

Before resolving any conflicts, mine historical "good" RNW-fork commits for conflict-resolution patterns. Create or update [references/conflict-patterns.md](./references/conflict-patterns.md).

Reference commits to study:
```
ceeaddc0d19161e4fa0e01139a721b758d0269ce
9f26c15efab7b51dd8544f50d2a26905bb875223
1d7f44c4ad58a3ffa506cdc618c92d0dcebaf238
e5d505e43d47a7cc603cd1be3d875dc0e3ab6ab9
3e3b133fcb32f39f485b075858eaa7ff55d0d912
9b40dac70b27ec2e5c3d0449bca50c841764e413
d73784caa0d7e91a6c20fa485cf9ccb7923a1d40
b6315a67451f9a2526ba1a5f3814d4ca6564342c
bb50808b9f7e63da8af5511bf4b2faf064add19f
```

For each commit:
- Identify files where merge conflicts were resolved
- Extract BEFORE/AFTER snippets for each resolved hunk (summarise if large)
- Categorise into reusable patterns (name + signals + anti-signals)
- Include example references (commit + file path + short diff summary)
- Include safety notes: intentional markers, flowconfig rule, E2E override markers

#### Phase 2 — Discover Conflicts and Split into Hunks

Scan the repository for conflict markers:

```powershell
# Find all files with conflict markers (excluding node_modules, intentional files)
$conflictFiles = Get-ChildItem -Path . -Recurse -File |
    Where-Object { $_.FullName -notlike "*node_modules*" -and $_.Name -ne "flowconfig.windows.conflict" } |
    ForEach-Object {
        $content = Get-Content -Path $_.FullName -Raw -ErrorAction SilentlyContinue
        if ($content -match '<<<<<<<') { $_.FullName }
    }

Write-Host "=== Files with conflict markers ==="
$conflictFiles | ForEach-Object { Write-Host "  - $_" }
Write-Host "Total: $($conflictFiles.Count) files"
```

Split each conflicted file into individual hunks for review.

#### Phase 3 — Propose Resolution (Pattern-First, No Auto-Apply)

**IMPORTANT: Guard against "previously-intentionally-skipped" upstream changes.**

In some prior RNW integrations, certain upstream changes were intentionally NOT taken for specific files (e.g., because RNW has a divergent Windows copy, platform overrides, or intentional conflict markers). In later integrations, those same upstream changes may reappear and must NOT be automatically accepted.

**Before resolving any conflict hunk**, you MUST first inspect the actual upstream change using the compare URL:

- **Compare URL format:** `https://github.com/facebook/react-native/compare/<previous-commit>...<target-commit>`
  - LEFT = previous nightly version commit hash (from `$currentVersion`)
  - RIGHT = target nightly version commit hash (from `$targetVersion`)
  - Example: `https://github.com/facebook/react-native/compare/58bc6c3e3...f15985f4f`

**Required steps for each hunk:**

1. **Inspect upstream changes** via the compare URL:
   - Identify the exact files changed upstream
   - Determine what lines/sections changed and why (intent)
2. **Compare against the RNW Windows-copy** of the file:
   - If the RNW file is a direct copy → upstream changes usually apply (unless conflict-patterns indicates otherwise)
   - If RNW contains Windows-only edits (often marked with `// [Windows`) or is substantially different → upstream changes may be intentionally NOT applicable
3. **Check references/conflict-patterns.md** for a matching "intentional skip / divergence" pattern and apply that guidance first
4. **Only THEN** propose a hunk resolution using the structured prompt system (merge prompt + file-type prompts + source-folder instructions) and run validation to output confidence (`Low`/`Medium`/`High`)
5. **If the upstream change was intentionally skipped in a previous integration**, do NOT accept it automatically even if it reappears now:
   - Prefer the documented RNW pattern ("skip/retain RNW version") and explain the rationale
   - Set confidence to `Low` or `Medium` as appropriate and request human approval

**Output requirement for each hunk proposal:**
- The compare URL used
- A 1-2 line summary of what upstream changed
- Why we should or should not take it in RNW
- Confidence level (`Low`/`Medium`/`High`)
- Request for approval before applying

**CRITICAL: Separate upstream changes — do NOT bundle unrelated changes into one resolution.**

When the THEIRS (upstream) side contains MULTIPLE independent changes (e.g., a syntax rename `$ReadOnly` → `Readonly` AND a semantic change like adding `Omit<>`), treat each change independently:
- Only apply the change that directly caused the conflict (usually the syntax/formatting change)
- Do NOT silently adopt additional semantic changes (new props, `Omit<>`, added/removed parameters) from THEIRS unless they are explicitly part of the same conflict region AND you have confirmed via the compare URL that the semantic change is safe for RNW
- If THEIRS has both a syntax change and a semantic change, propose ONLY the syntax change merged with OURS content, and separately flag the semantic change for review
- When in doubt, keep OURS content and only apply the minimal syntax fix from THEIRS

Example of what NOT to do:
```
THEIRS: Readonly<{ ...Omit<ViewProps, 'experimental_accessibilityOrder'>,
OURS:   $ReadOnly<{ ...ViewProps,

WRONG resolution:  Readonly<{ ...Omit<ViewProps, 'experimental_accessibilityOrder'>,  ← silently adopted Omit from upstream
CORRECT resolution: Readonly<{ ...ViewProps,  ← only took the syntax change, kept OURS content
```

**CRITICAL: Line-by-line diff the OURS and THEIRS blocks before proposing.**

Before proposing any resolution, explicitly diff the OURS and THEIRS blocks line by line:
1. Identify EVERY difference between OURS and THEIRS (not just the obvious one like `$ReadOnly` → `Readonly`)
2. Classify each difference as either:
   - **Syntax-only** (e.g., `$ReadOnly` → `Readonly`, `$FlowFixMe[incompatible-return]` → `$FlowFixMe[incompatible-type]`) — safe to take from THEIRS
   - **Content addition in THEIRS** (e.g., new props, `Omit<>` additions, new parameters) — do NOT take unless confirmed safe
   - **Content in OURS not in THEIRS** (e.g., Windows-specific types, `// [Windows` blocks) — ALWAYS keep
3. The proposed resolution MUST be: OURS content + only syntax-only fixes from THEIRS
4. If OURS had no wrapper (e.g., `type Props = {` without `$ReadOnly`) and THEIRS adds one (`Readonly<{`), keep OURS as-is — do NOT add wrappers that OURS didn't have
5. If OURS uses exact objects (`{||}`, `{|`) and THEIRS uses inexact (`{}`, `{`), keep OURS exact syntax

---

For each hunk, generate a PROPOSAL:

1. **Analysis**: Show OURS (RNW fork side) vs THEIRS (upstream side) with surrounding context
2. **Pattern match**: Attempt to match against patterns in [references/conflict-patterns.md](./references/conflict-patterns.md)
3. **Proposed merged output**: Apply merge prompt + file-type rules + folder-specific bias
4. **Validation**: Judge correctness + risk, assign confidence: `Low` / `Medium` / `High`
5. **Approval request** (REQUIRED for each hunk):
   - Present: file path, hunk index, "what changed" summary, confidence, exact replacement text
   - Ask: "Approve applying this hunk? (Yes/No)"
   - If No: propose alternative OR provide manual steps
   - If Low confidence: do NOT propose auto-application; provide manual-resolution plan instead

#### Phase 3b — Present Detailed Per-Hunk Proposals

After generating the batch summary table, present EACH hunk individually for review. For every hunk show:

1. **Header**: File path, hunk index (e.g., "Hunk 1/2"), line numbers
2. **OURS block**: The exact `=======` to `>>>>>>>` content (RNW Override side)
3. **THEIRS block**: The exact `<<<<<<<` to `=======` content (Upstream side)
4. **Surrounding context**: 3-5 lines before `<<<<<<<` and after `>>>>>>>`
5. **Pattern matched**: Which pattern from `references/conflict-patterns.md` applies (P1-P7)
6. **Compare URL**: The upstream compare link used
7. **Upstream intent**: 1-2 line summary of what upstream changed and why
8. **Proposed resolution**: The exact replacement text that would replace the entire conflict block (from `<<<<<<<` through `>>>>>>>` inclusive)
9. **Confidence**: `Low` / `Medium` / `High`
10. **Approval prompt**: "Approve applying this hunk? (Yes/No)"

Wait for the user's response before proceeding to the next hunk. If the user says:
- **Yes**: Apply the replacement immediately, confirm, then show next hunk
- **No**: Ask if they want an alternative proposal, manual steps, or to skip
- **Skip**: Leave conflict markers in place, move to next hunk
- **Yes to all remaining**: Apply all remaining hunks without further prompts (only if all are High confidence)

**File-type specific rules:**
- `.js`/`.ts`/`.tsx`: Preserve `// [Windows` sections; prefer upstream for pure formatting changes
- `.cpp`/`.h`: Check for `#ifdef WINDOWS` / platform-specific guards; upstream-first for shared code
- `.flowconfig`/config files: Keep RNW-specific entries, add new upstream entries
- `package.json`: Use target nightly version for all RN-related deps

**Folder-specific bias:**
- `vnext/src-win/`: Bias toward RNW (OURS) — these are Windows-specific overrides
- `packages/@office-iss/`: Bias toward RNW (OURS) — Win32-specific
- `packages/@react-native/tester/`: Bias toward upstream (THEIRS) — should match upstream
- `vnext/ReactCopies/`: Bias toward upstream (THEIRS) — should be exact copies

#### Phase 4 — Apply (Only After Per-Hunk Approval)

After explicit approval for a hunk:
- Replace the original conflict block with the validated "Resolved Hunk"
- Never touch intentional markers (E2E platform override files)
- Never remove the `flowconfig.windows.conflict` conflict

After all hunks are resolved:

```powershell
# Verify no unintentional conflict markers remain
$remaining = Get-ChildItem -Path . -Recurse -File |
    Where-Object { $_.FullName -notlike "*node_modules*" -and $_.Name -ne "flowconfig.windows.conflict" } |
    ForEach-Object {
        $content = Get-Content -Path $_.FullName -Raw -ErrorAction SilentlyContinue
        if ($content -match '<<<<<<<') { $_.FullName }
    }

if ($remaining.Count -eq 0) {
    Write-Host "All conflicts resolved!"
} else {
    Write-Host "WARNING: $($remaining.Count) files still have conflict markers"
    $remaining | ForEach-Object { Write-Host "  - $_" }
}

# Commit resolved conflicts
git add -A
git commit -m "Resolve merge conflicts for RN $targetVersion integration"
```

After completing this step, confirm: **Step 12 completed successfully.**

### Step 13: Post-Merge RNW Playground Validation (Mandatory)

After resolving merge conflicts, perform an initial functional smoke check by building and running RNW Playground locally.

#### Build and Run Playground

First, ensure the yarn lockfile is up to date (upstream dependency changes during integration may have introduced new packages):

```powershell
yarn install
```

If the lockfile changed, commit it before building:

```powershell
git add yarn.lock
git diff --cached --quiet yarn.lock || git commit -m "Update yarn.lock for RN $targetVersion integration"
```

Then build the Playground:

```powershell
# Find MSBuild path
$msbuild = & "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe" -latest -requires Microsoft.Component.MSBuild -find MSBuild\**\Bin\MSBuild.exe
Write-Host "MSBuild: $msbuild"

# Build the Playground composition via the solution (required for SolutionPath property)
# Target only the playground-composition.Package project
& $msbuild packages/playground/windows/playground-composition.sln /t:playground-composition_Package /p:Configuration=Debug /p:Platform=x64 /p:RestoreLockedMode=false /m

# If build succeeds, launch the app to verify runtime behavior
```

The solution file is at: `packages/playground/windows/playground-composition.sln`
The target project is: `playground-composition.Package` (built via `/t:playground-composition_Package`)

#### If Playground Fails to Build or Run

Some integration failures are caused by upstream changes that were previously fixed during earlier RNW integrations via patches applied in the RNW forked repository. The following commits contain known previous integration build/runtime fixes:

```
885aa5b51f1b4493a4bed16fce846270adb44d70
01bfeefcb58a0688713c42b5c5b867319a25029e
76a133e7ff81e148db6a9cd1d7d4c7a7aca86cb6
477ea4915576235f82e2b6349917f345ce929180
21285f1247cec3bb9667859c5698d10930eefd1b
9a2e17697526ed219a33d96f7acf0903669f7585
aabe43e85e3e201ab99e0ac71ef6ee7dcf442110
5a6fdb82771e9cbc6ee019dab5766f03761df6d0
48e7a08931a59be27cc8709a511b7c6aea3d6900
61392d901dd036b3abe456de1f5ace8571954811
9fb535e0285883ba95b39018d26ff2ba7b876d53
cf1e9188c391c0411205657bbdcd8feb5d851fc4
```

#### Recovery Workflow

For EACH commit listed above:

1. **Inspect the commit** in the RNW forked repository:
   - Identify which files were changed
   - Determine what build/runtime issue the change addressed
   - Check whether the affected code paths exist in the current merged state

2. **Validate relevance** BEFORE applying any change:
   - Confirm the same issue is occurring in the current Playground failure
   - Check if the fix is still relevant in the current upstream context
   - Validate the compare diff
   - Ensure the fix does not conflict with:
     - RNW Windows-specific adaptations
     - Intentionally skipped upstream changes
     - Entries documented in `references/conflict-patterns.md`

3. **Prepare a FIX PROPOSAL and request approval:**

   Present:
   - Commit hash being considered
   - Files impacted
   - Short description of the original issue the fix addressed
   - Why this fix is applicable to the current failure
   - Exact proposed patch/diff to apply
   - Confidence level (`Low` / `Medium` / `High`)

   Ask explicitly: **"Approve applying this fix? (Yes/No)"**

4. **Apply ONLY after explicit approval.**

   If confidence is `Low`:
   - Do NOT apply automatically
   - Provide manual investigation guidance instead
   - Request further direction

#### Recovery Log

Maintain a recovery log for each evaluated commit:

| Commit | Issue Matched | Confidence | Approval | Applied/Skipped |
|--------|--------------|------------|----------|-----------------|
| `885aa5b...` | (description) | High/Med/Low | Yes/No | Applied/Skipped |
| ... | ... | ... | ... | ... |

After all fixes are applied and Playground builds successfully:

```powershell
git add -A
git commit -m "Apply build fixes for RN $targetVersion integration"
```

After completing this step, confirm: **Step 13 completed successfully.**

### Step 14: Deploy and Launch Playground

After the build succeeds, deploy and launch the Playground app to verify runtime behavior.

**IMPORTANT: Debug builds are NOT signed.** Do NOT attempt to install via MSIX (`Add-AppxPackage -Path *.msix`) — it will fail with `0x800B0100: No signature was present`. Instead, use **loose layout registration** via `Add-AppxPackage -Register <AppxManifest.xml>`, which does not require signing or certificates.

```powershell
# Register the app from the loose layout (no signing needed for debug builds)
$appxManifest = "packages\playground\windows\playground-composition.Package\bin\x64\Debug\AppX\AppxManifest.xml"

if (Test-Path $appxManifest) {
    Write-Host "Registering app from: $appxManifest"
    Add-AppxPackage -Register $appxManifest -ForceApplicationShutdown
} else {
    # Fallback: search for AppxManifest.xml in build output
    $appxManifest = Get-ChildItem -Path "packages\playground\windows" -Filter "AppxManifest.xml" -Recurse -ErrorAction SilentlyContinue |
        Where-Object { $_.FullName -like "*bin*Debug*AppX*" } |
        Select-Object -First 1 -ExpandProperty FullName
    if ($appxManifest) {
        Write-Host "Registering app from: $appxManifest"
        Add-AppxPackage -Register $appxManifest -ForceApplicationShutdown
    } else {
        Write-Host "ERROR: No AppxManifest.xml found. Build may have failed."
    }
}

# Launch the app
$appPackage = Get-AppxPackage -Name "*playground*" | Select-Object -First 1
if ($appPackage) {
    $appId = (Get-AppxPackageManifest $appPackage).Package.Applications.Application.Id
    $fullName = $appPackage.PackageFamilyName
    Write-Host "Launching: $fullName!$appId"
    Start-Process "shell:AppsFolder\$fullName!$appId"
    Write-Host "Playground launched successfully. Verify the app renders correctly."
} else {
    Write-Host "WARNING: Could not find installed Playground package. Try deploying from Visual Studio."
}
```

After verifying the app launches and renders correctly:
- Check that the main screen loads without crashes
- Verify basic component rendering (text, buttons, views)
- Check the debug console for any runtime errors

After completing this step, confirm: **Step 14 completed successfully.**

## Key Files to Update

When integrating a new nightly version, these files typically need updates:

| File | Dependencies to Update |
|------|----------------------|
| `vnext/package.json` | `react-native`, `@react-native/*` packages |
| `package.json` (root) | `react-native` in resolutions |
| Various app `package.json` files | Peer dependencies |

## Notes

- The major version (e.g., 0.84 → 0.85) may change between nightlies
- Always verify the target version exists before updating dependencies