Register the catalyst app with LaunchServices in the path that builds it

The Appium mac2 driver resolves the app through LaunchServices by bundleId, and
a freshly built Catalyst .app is not registered there, so OneTimeSetUp fails for
every test with "The app representing com.microsoft.maui.uitests could not be
found". BuildAndRunHostApp.ps1 documents this and calls lsregister -f, but the
replication verification path never runs that script - across the 22 cached logs
carrying this error, lsregister appears zero times.

All 22 are catalyst and all 22 blocked with nothing published: 14% of the 160
cached catalyst runs. It is intermittent only because agents are reused and a
warm agent keeps the earlier registration.

Registers the bundle in Build-AndDeploy.ps1's catalyst branch, probing both
known lsregister paths, exporting MAC_APP_PATH, and checking the exit code
rather than claiming success unconditionally.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 735ac9a2-7bec-4baa-ad19-c298e5bc795a

Author: Copilot CI

.github/scripts/Replication-Pipeline.Tests.ps1

@@ -1377,3 +1377,50 @@ Describe 'An already-covered issue may be re-run deliberately' {
         $splat | Should -BeGreaterThan 0
     }
 }
+
+Describe 'The catalyst build registers its app where the mac2 driver looks' {
+    # Every one of the 22 cached runs that failed with "The app representing
+    # com.microsoft.maui.uitests could not be found" was catalyst, and every one
+    # was blocked with nothing published - 14% of all cached catalyst runs.
+    # BuildAndRunHostApp.ps1 documents the cause and registers the bundle, but
+    # the replication verification path never calls it: `lsregister` appeared
+    # zero times in all 22 logs. Build-AndDeploy.ps1 is the script that path
+    # does run, and it believed "no install step needed".
+    BeforeAll {
+        $script:DeploySource = Get-Content -Raw -LiteralPath (Join-Path $PSScriptRoot 'shared/Build-AndDeploy.ps1')
+        $catalystStart = $script:DeploySource.IndexOf('$Platform -eq "catalyst"')
+        $windowsStart = $script:DeploySource.IndexOf('$Platform -eq "windows"')
+        $script:CatalystBranch = $script:DeploySource.Substring($catalystStart, $windowsStart - $catalystStart)
+    }
+
+    It 'registers the built bundle with LaunchServices' {
+        $script:CatalystBranch | Should -Match 'lsregister'
+    }
+
+    It 'probes both known lsregister locations' {
+        # A single hard-coded path silently skips registration on an agent whose
+        # framework symlink layout differs, which looks exactly like the bug.
+        ([regex]::Matches($script:CatalystBranch, 'LaunchServices\.framework')).Count |
+            Should -BeGreaterThan 1
+    }
+
+    It 'reports a failed registration instead of claiming success' {
+        # Claiming success unconditionally is how a failed registration becomes
+        # an unexplained Appium error several attempts later.
+        $success = $script:CatalystBranch.IndexOf('Registered MacCatalyst app with LaunchServices')
+        $check = $script:CatalystBranch.IndexOf('$LASTEXITCODE -eq 0')
+        $check | Should -BeGreaterThan 0
+        $check | Should -BeLessThan $success
+    }
+
+    It 'exposes the bundle path for the mac2 driver as well' {
+        # bundleId resolution is primary, but options.App still needs the path.
+        $script:CatalystBranch | Should -Match 'MAC_APP_PATH'
+    }
+
+    It 'does not fail the build when registration is unavailable' {
+        # On an agent where the bundle is already registered the run still
+        # works; hard-failing would break runs that pass today.
+        $script:CatalystBranch | Should -Not -Match 'lsregister not found[^\r\n]*\r?\n\s*exit 1'
+    }
+}

.github/scripts/shared/Build-AndDeploy.ps1

@@ -414,8 +414,76 @@ if ($Platform -eq "android") {
 
     Write-Success "Build completed in $($buildDuration.TotalSeconds) seconds"
 
-    # MacCatalyst apps run directly on the Mac - no install step needed
-    # The test framework (Appium) will launch the app directly
+    # MacCatalyst apps run directly on the Mac, so there is no install step -
+    # but "no install" is not the same as "nothing to do". The Appium mac2
+    # driver (WebDriverAgentMac) resolves the app through LaunchServices via
+    # the bundleId capability, and a freshly built Catalyst .app has never been
+    # registered there. When the lookup fails, OneTimeSetUp fails for EVERY
+    # test in the run with "The app representing com.microsoft.maui.uitests
+    # could not be found", which reads like a harness outage rather than a
+    # missing registration. Setting MAC_APP_PATH / options.App alone is NOT
+    # sufficient, because the driver still resolves by bundleId first.
+    #
+    # BuildAndRunHostApp.ps1 already documents this and registers the bundle,
+    # but the replication verification path never calls it: across the 22
+    # cached runs that hit this error - every one of them catalyst, and every
+    # one blocked with nothing published - `lsregister` appears zero times.
+    # That is 14% of all cached catalyst runs lost to a missing one-line step.
+    # It is intermittent rather than universal because agents are reused, so a
+    # warm agent can still carry the registration from an earlier run.
+    #
+    # Registration failure is deliberately a warning and not a build failure:
+    # on an agent where the bundle is already registered the run still works,
+    # and turning that into a hard failure would break runs that pass today.
+    $catalystAppPath = $null
+    $searchPath = Split-Path -Parent $ProjectPath
+    $artifactsDir = $null
+    while ($searchPath -and -not $artifactsDir) {
+        $testPath = Join-Path $searchPath "artifacts"
+        if (Test-Path $testPath) { $artifactsDir = $testPath; break }
+        $parent = Split-Path -Parent $searchPath
+        if ($parent -eq $searchPath) { break }
+        $searchPath = $parent
+    }
+
+    if ($artifactsDir) {
+        $catalystAppPath = Get-ChildItem -Path $artifactsDir -Filter "*.app" -Recurse -ErrorAction SilentlyContinue |
+            Where-Object {
+                $_.FullName -match "$Configuration.*$macRid.*$projectName" -and
+                $_.FullName -notmatch "[\\/]obj[\\/]"
+            } |
+            Select-Object -First 1
+    }
+
+    if ($catalystAppPath) {
+        $env:MAC_APP_PATH = $catalystAppPath.FullName
+        Write-Info "MacCatalyst app bundle: $($catalystAppPath.FullName)"
+
+        # Probe both known lsregister locations so a differing framework
+        # symlink layout on any agent macOS version cannot silently skip
+        # registration.
+        $lsregisterCandidates = @(
+            "/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister",
+            "/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister"
+        )
+        $lsregister = $lsregisterCandidates | Where-Object { Test-Path $_ } | Select-Object -First 1
+        if ($lsregister) {
+            & $lsregister -f $catalystAppPath.FullName 2>&1 | Out-Null
+            # Report the actual result. Claiming success unconditionally is how
+            # a failed registration turns into an unexplained Appium error four
+            # attempts later.
+            if ($LASTEXITCODE -eq 0) {
+                Write-Success "Registered MacCatalyst app with LaunchServices"
+            } else {
+                Write-Warn "lsregister exited $LASTEXITCODE; the mac2 driver may not resolve the bundle by id"
+            }
+        } else {
+            Write-Warn "lsregister not found at any known path; skipping LaunchServices registration"
+        }
+    } else {
+        Write-Warn "Could not locate the built MacCatalyst .app under $artifactsDir; skipping LaunchServices registration"
+    }
+
     Write-Success "MacCatalyst app ready (runs on host Mac)"
 
     #endregion