fix(mobile): accept three packaged documents and drop stale generations on close

Codex review of the native store: Swift and Kotlin both accept the mermaid
frame as a third document, remove superseded generations once their last
session closes, and the session hook retries once per build id so a
desktop upgrade gets its own recovery.

Claude-Session: https://claude.ai/code/session_01JNnE9qzUZMMnqpZWCqM3nb

mobile/packages/expo-mobile-web-shell/android/src/main/java/expo/modules/mobilewebshell/MobileWebPackageStore.kt

@@ -173,7 +173,11 @@ internal class MobileWebPackageStore internal constructor(
 
   @Synchronized
   fun closeSession(sessionId: String) {
-    sessions.remove(sessionId)
+    val session = sessions.remove(sessionId) ?: return
+    runCatching {
+      val generations = File(File(cacheRoot, session.hostKey), "generations")
+      removeOtherGenerations(generations, session.hostKey, requestedBuildId(generations, null))
+    }
   }
 
   @Synchronized
@@ -329,7 +333,7 @@ internal class MobileWebPackageStore internal constructor(
     val assets = parsedAssets(assetValues)
     require(
       assets.values.sumOf { it.byteLength } == declaredTotalBytes &&
-        assets.values.count { it.role == "document" } in 1..2 &&
+        assets.values.count { it.role == "document" } in 1..MOBILE_WEB_DOCUMENT_PATHS.size &&
         entrypoint == "index.html" &&
         assets[entrypoint]?.role == "document"
     ) { "mobile_web_manifest_invalid" }

mobile/packages/expo-mobile-web-shell/android/src/test/java/expo/modules/mobilewebshell/MobileWebPackageStoreTest.kt

@@ -51,6 +51,31 @@ class MobileWebPackageStoreTest {
     )
   }
 
+  @Test
+  fun commitsAllPackagedDocuments() {
+    val store = jvmMobileWebPackageStore(temporary.newFolder())
+    val paths = listOf("index.html", "markdown-editor.html", "mermaid-frame.html")
+    val fixture = mobileWebStoreFixture { manifest ->
+      val asset = manifest.getJSONArray("assets").getJSONObject(0)
+      manifest.put("assets", org.json.JSONArray(paths.map { path ->
+        JSONObject(asset.toString()).put("path", path)
+      }))
+      manifest.put("totalBytes", manifest.getInt("totalBytes") * paths.size)
+    }
+    paths.forEach { path ->
+      store.writeStagedAsset(
+        "paired-host", fixture.buildId, path, Base64.getEncoder().encodeToString(fixture.bytes)
+      )
+    }
+    store.commitGeneration("paired-host", fixture.buildId, fixture.manifestJson)
+    val session = store.openSession("paired-host", fixture.buildId, 1)
+    paths.forEach { path ->
+      val asset = store.readAsset(session.getValue("sessionId"), path)
+      assertArrayEquals(fixture.bytes, asset.bytes)
+      assertTrue(asset.isDocument)
+    }
+  }
+
   @Test
   fun rejectsManifestsThatDoNotHashToTheBuildId() {
     val root = temporary.newFolder()
@@ -363,7 +388,6 @@ class MobileWebPackageStoreTest {
 
     store.closeSession(previousSession.getValue("sessionId"))
     store.closeSession(active.getValue("sessionId"))
-    store.commitFixture("paired-host", current)
 
     assertEquals(
       listOf(current.buildId),

mobile/packages/expo-mobile-web-shell/ios-tests/MobileWebPackageStoreTests.swift

@@ -11,6 +11,7 @@ enum MobileWebPackageStoreTests {
     defer { try? FileManager.default.removeItem(at: root) }
 
     try commitsAndReadsExactGeneration(root: root.appendingPathComponent("verified"))
+    try commitsAllPackagedDocuments(root: root.appendingPathComponent("all-documents"))
     try rejectsMalformedManifests(root: root.appendingPathComponent("manifests"))
     acceptsOnlyExactCanonicalAssetPaths()
     acceptsOnlyExactSha256Tokens()
@@ -94,6 +95,36 @@ enum MobileWebPackageStoreTests {
     precondition(staged?.isEmpty != false)
   }
 
+  private static func commitsAllPackagedDocuments(root: URL) throws {
+    let store = MobileWebPackageStore(cacheRoot: root)
+    let paths = ["index.html", "markdown-editor.html", "mermaid-frame.html"]
+    let fixture = try mobileWebStoreFixture { manifest in
+      let asset = (manifest["assets"] as! [[String: Any]])[0]
+      manifest["assets"] = paths.map { path in
+        var document = asset
+        document["path"] = path
+        return document
+      }
+      manifest["totalBytes"] = (manifest["totalBytes"] as! Int) * paths.count
+    }
+    for path in paths {
+      try store.writeStagedAsset(
+        hostIdentity: "paired-host", buildId: fixture.buildId, path: path,
+        dataBase64: fixture.bytes.base64EncodedString()
+      )
+    }
+    try store.commitGeneration(
+      hostIdentity: "paired-host", buildId: fixture.buildId, manifestJson: fixture.manifestJson
+    )
+    let session = try store.openSession(
+      hostIdentity: "paired-host", buildId: fixture.buildId, bridgeVersion: 1
+    )
+    for path in paths {
+      let asset = try store.readAsset(sessionId: session["sessionId"]!, path: path)
+      precondition(asset.data == fixture.bytes && asset.isDocument)
+    }
+  }
+
   private static func rejectsMalformedManifests(root: URL) throws {
     let store = MobileWebPackageStore(cacheRoot: root)
     let valid = try mobileWebStoreFixture()
@@ -526,7 +557,6 @@ enum MobileWebPackageStoreTests {
 
     store.closeSession(sessionId: previousSession["sessionId"]!)
     store.closeSession(sessionId: active["sessionId"]!)
-    try mobileWebStoreCommit(store: store, host: "paired-host", fixture: current)
 
     let generations = mobileWebStoreHostRoot(cacheRoot: root, host: "paired-host")
       .appendingPathComponent("generations")

mobile/packages/expo-mobile-web-shell/ios/MobileWebPackageStore.swift

@@ -210,7 +210,15 @@ final class MobileWebPackageStore {
 
   func closeSession(sessionId: String) {
     locked {
-      _ = sessions.removeValue(forKey: sessionId)
+      guard let session = sessions.removeValue(forKey: sessionId),
+        let root = try? cacheRoot()
+      else { return }
+      let generations = root.appendingPathComponent(session.hostKey, isDirectory: true)
+        .appendingPathComponent("generations", isDirectory: true)
+      guard let newest = try? requestedBuildId(generations: generations, buildId: nil) else { return }
+      try? removeOtherGenerations(
+        generations: generations, hostKey: session.hostKey, keeping: newest, cacheRoot: root
+      )
     }
   }
 
@@ -403,7 +411,7 @@ final class MobileWebPackageStore {
     }
     guard
       totalBytes == declaredTotalBytes,
-      (1...2).contains(documentCount),
+      (1...mobileWebDocumentPaths.count).contains(documentCount),
       entrypoint == "index.html",
       records[entrypoint]?.role == "document"
     else {