Resolve crash when changing orientation with settings open.

app/src/main/java/org/thoughtcrime/securesms/chats/ChatsNavigation.kt

@@ -30,6 +30,7 @@ import kotlinx.coroutines.launch
 import org.signal.core.ui.navigation.TransitionSpecs
 import org.thoughtcrime.securesms.MainNavigator
 import org.thoughtcrime.securesms.components.settings.conversation.ConversationSettingsNavHostFragment
+import org.thoughtcrime.securesms.compose.AndroidNavHostFragment
 import org.thoughtcrime.securesms.compose.FragmentBackHandler
 import org.thoughtcrime.securesms.compose.FragmentBackPressedState
 import org.thoughtcrime.securesms.conversation.ConversationIntents
@@ -141,7 +142,7 @@ private fun ConversationSettingsEntry(route: MainNavigationDetailLocation.Chats.
     val backPressedState = remember { FragmentBackPressedState() }
     FragmentBackHandler(backPressedState)
 
-    AndroidFragment(
+    AndroidNavHostFragment(
       clazz = ConversationSettingsNavHostFragment::class.java,
       fragmentState = fragmentState,
       arguments = args,

app/src/main/java/org/thoughtcrime/securesms/compose/AndroidNavHostFragment.kt

@@ -0,0 +1,107 @@
+/*
+ * Copyright 2026 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.thoughtcrime.securesms.compose
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Modifier
+import androidx.core.os.bundleOf
+import androidx.fragment.app.Fragment
+import androidx.fragment.app.FragmentContainerView
+import androidx.fragment.app.FragmentFactory
+import androidx.fragment.app.commitNow
+import androidx.fragment.compose.AndroidFragment
+import androidx.fragment.compose.FragmentState
+import androidx.fragment.compose.rememberFragmentState
+import androidx.navigation.fragment.NavHostFragment
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flowOf
+import org.thoughtcrime.securesms.R
+
+/**
+ * Hosts a [NavHostFragment] inside Compose.
+ *
+ * [AndroidFragment] cannot host a [NavHostFragment] directly. It gives its container a
+ * composition-derived id, and [NavHostFragment] reuses its own container id for the destinations it
+ * navigates to. That id is written into the saved child-fragment state, so once the screen is
+ * restored the child [androidx.fragment.app.FragmentManager] looks for a container id that no longer
+ * exists and throws "No view found for id ...".
+ *
+ * Interposing [NavHostWrapperFragment] gives the nav host a container with a stable resource id,
+ * which survives configuration changes and process death.
+ */
+@Composable
+fun AndroidNavHostFragment(
+  clazz: Class<out NavHostFragment>,
+  modifier: Modifier = Modifier,
+  fragmentState: FragmentState = rememberFragmentState(),
+  arguments: Bundle = Bundle.EMPTY,
+  onUpdate: (Fragment) -> Unit = {}
+) {
+  val wrapperArguments = remember(clazz, arguments) { NavHostWrapperFragment.createArgs(clazz, arguments) }
+
+  AndroidFragment(
+    clazz = NavHostWrapperFragment::class.java,
+    modifier = modifier,
+    fragmentState = fragmentState,
+    arguments = wrapperArguments,
+    onUpdate = onUpdate
+  )
+}
+
+/**
+ * Hosts a [NavHostFragment] in a container with a stable id. Use via [AndroidNavHostFragment].
+ */
+class NavHostWrapperFragment : Fragment(), FragmentBackPressedInfoProvider {
+
+  companion object {
+    private const val ARG_NAV_HOST_CLASS_NAME = "nav_host_wrapper.class_name"
+    private const val ARG_NAV_HOST_ARGUMENTS = "nav_host_wrapper.arguments"
+
+    fun createArgs(clazz: Class<out NavHostFragment>, arguments: Bundle): Bundle {
+      return bundleOf(
+        ARG_NAV_HOST_CLASS_NAME to clazz.name,
+        ARG_NAV_HOST_ARGUMENTS to arguments
+      )
+    }
+  }
+
+  private val navHostFragment: NavHostFragment?
+    get() = childFragmentManager.findFragmentById(R.id.nav_host_wrapper_container) as? NavHostFragment
+
+  override fun onCreate(savedInstanceState: Bundle?) {
+    super.onCreate(savedInstanceState)
+
+    if (navHostFragment != null) {
+      return
+    }
+
+    val args = requireArguments()
+    val className = requireNotNull(args.getString(ARG_NAV_HOST_CLASS_NAME)) { "No nav host class name in arguments." }
+    val navHostClass = FragmentFactory.loadFragmentClass(requireContext().classLoader, className)
+
+    childFragmentManager.commitNow {
+      setReorderingAllowed(true)
+      add(R.id.nav_host_wrapper_container, navHostClass, args.getBundle(ARG_NAV_HOST_ARGUMENTS))
+    }
+  }
+
+  override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
+    return FragmentContainerView(inflater.context).apply {
+      id = R.id.nav_host_wrapper_container
+      layoutParams = ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)
+    }
+  }
+
+  override fun getFragmentBackPressedInfo(): Flow<FragmentBackPressedInfo> {
+    val provider = navHostFragment as? FragmentBackPressedInfoProvider
+    return provider?.getFragmentBackPressedInfo() ?: flowOf(FragmentBackPressedInfo.Disabled)
+  }
+}

app/src/main/res/values/ids.xml

@@ -32,4 +32,6 @@
     <item name="edittext_monospace" type="id" />
     <item name="edittext_spoiler" type="id" />
     <item name="edittext_clear_formatting" type="id" />
+
+    <item name="nav_host_wrapper_container" type="id" />
 </resources>