android: do not stop running on login, and edit prefs after startLogi… (#659)

android: do not stop running on login, and edit prefs after startLoginInteractive

Previously: start, edit prefs with wantRunning=false, then startLoginInteractive
Now: 1. editPrefs() with WantRunning=true, LoggedOut=false if AuthKey != null
     2. start() -> boots tailscaled
     3. startLoginInteractive()
Do not call wantRunning=false; the route clearing issue requiring that is resolved.

This also:
-add deepCopy function which copies MaskedPrefs. Note that .copy() does not copy the non-constructor parameters
-removes InternalExitNodePriorSet in MaskedPrefs, since this can't be set on the client

Updates tailscale/corp#24002

Signed-off-by: kari-ts <kari@tailscale.com>

android/src/main/java/com/tailscale/ipn/ui/model/Ipn.kt

@@ -4,9 +4,9 @@
 package com.tailscale.ipn.ui.model
 
 import android.net.Uri
-import java.util.UUID
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.Transient
+import java.util.UUID
 
 class Ipn {
 
@@ -95,11 +95,11 @@ class Ipn {
       var ExitNodeIDSet: Boolean? = null,
       var ExitNodeAllowLANAccessSet: Boolean? = null,
       var WantRunningSet: Boolean? = null,
+      var LoggedOutSet: Boolean? = null,
       var ShieldsUpSet: Boolean? = null,
       var AdvertiseRoutesSet: Boolean? = null,
       var ForceDaemonSet: Boolean? = null,
       var HostnameSet: Boolean? = null,
-      var InternalExitNodePriorSet: Boolean? = null,
   ) {
 
     var ControlURL: String? = null
@@ -126,12 +126,6 @@ class Ipn {
         ExitNodeIDSet = true
       }
 
-    var InternalExitNodePrior: String? = null
-      set(value) {
-        field = value
-        InternalExitNodePriorSet = true
-      }
-
     var ExitNodeAllowLANAccess: Boolean? = null
       set(value) {
         field = value
@@ -144,6 +138,12 @@ class Ipn {
         WantRunningSet = true
       }
 
+    var LoggedOut: Boolean? = null
+      set(value) {
+        field = value
+        LoggedOutSet = true
+      }
+
     var ShieldsUp: Boolean? = null
       set(value) {
         field = value
@@ -238,3 +238,20 @@ class Persist {
       var Provider: String = "",
   )
 }
+
+fun Ipn.MaskedPrefs.deepCopy(): Ipn.MaskedPrefs {
+  return Ipn.MaskedPrefs().also {
+    if (this.ControlURLSet == true) it.ControlURL = this.ControlURL
+    if (this.RouteAllSet == true) it.RouteAll = this.RouteAll
+    if (this.CorpDNSSet == true) it.CorpDNS = this.CorpDNS
+    if (this.ExitNodeIDSet == true) it.ExitNodeID = this.ExitNodeID
+    if (this.ExitNodeAllowLANAccessSet == true)
+        it.ExitNodeAllowLANAccess = this.ExitNodeAllowLANAccess
+    if (this.WantRunningSet == true) it.WantRunning = this.WantRunning
+    if (this.LoggedOutSet == true) it.LoggedOut = this.LoggedOut
+    if (this.ShieldsUpSet == true) it.ShieldsUp = this.ShieldsUp
+    if (this.AdvertiseRoutesSet == true) it.AdvertiseRoutes = this.AdvertiseRoutes
+    if (this.ForceDaemonSet == true) it.ForceDaemon = this.ForceDaemon
+    if (this.HostnameSet == true) it.Hostname = this.Hostname
+  }
+}

android/src/main/java/com/tailscale/ipn/ui/viewModel/IpnViewModel.kt

@@ -11,6 +11,7 @@ import com.tailscale.ipn.ui.localapi.Client
 import com.tailscale.ipn.ui.model.Ipn
 import com.tailscale.ipn.ui.model.IpnLocal
 import com.tailscale.ipn.ui.model.UserID
+import com.tailscale.ipn.ui.model.deepCopy
 import com.tailscale.ipn.ui.notifier.Notifier
 import com.tailscale.ipn.ui.util.AdvertisedRoutesHelper
 import com.tailscale.ipn.ui.util.LoadingIndicator
@@ -144,52 +145,54 @@ open class IpnViewModel : ViewModel() {
 
   // Login/Logout
 
+  /**
+   * Order of operations:
+   * 1. editPrefs() with maskedPrefs (to allow ControlURL override), WantRunning=true, LoggedOut=false if AuthKey != null  
+   * 2. start() starts the LocalBackend state machine
+   * 3. startLoginInteractive() is currently required for bother interactive and non-interactive (using auth key) login
+   *
+   * Any failure short‑circuits the chain and invokes completionHandler once.
+   */
   fun login(
       maskedPrefs: Ipn.MaskedPrefs? = null,
       authKey: String? = null,
       completionHandler: (Result<Unit>) -> Unit = {}
   ) {
+    val client = Client(viewModelScope)
 
-    val loginAction = {
-      Client(viewModelScope).startLoginInteractive { result ->
-        result
-            .onSuccess { TSLog.d(TAG, "Login started: $it") }
-            .onFailure { TSLog.e(TAG, "Error starting login: ${it.message}") }
-        completionHandler(result)
-      }
+    val finalMaskedPrefs = maskedPrefs?.deepCopy() ?: Ipn.MaskedPrefs()
+    finalMaskedPrefs.WantRunning = true
+    if (authKey != null) {
+      finalMaskedPrefs.LoggedOut = false
     }
 
-    // Need to stop running before logging in to clear routes:
-    // https://linear.app/tailscale/issue/ENG-3441/routesdns-is-not-cleared-when-switching-profiles-or-reauthenticating
-    val stopThenLogin = {
-      Client(viewModelScope).editPrefs(Ipn.MaskedPrefs().apply { WantRunning = false }) { result ->
-        result
-            .onSuccess { loginAction() }
-            .onFailure { TSLog.e(TAG, "Error setting wantRunning to false: ${it.message}") }
+    client.editPrefs(finalMaskedPrefs) { editResult ->
+      editResult
+          .onFailure {
+            TSLog.e(TAG, "editPrefs() failed: ${it.message}")
+            completionHandler(Result.failure(it))
           }
+          .onSuccess {
+            val opts = Ipn.Options(UpdatePrefs = editResult.getOrThrow(), AuthKey = authKey)
+            client.start(opts) { startResult ->
+              startResult
+                  .onFailure {
+                    TSLog.e(TAG, "start() failed: ${it.message}")
+                    completionHandler(Result.failure(it))
+                  }
+                  .onSuccess {
+                    client.startLoginInteractive { loginResult ->
+                      loginResult
+                          .onFailure {
+                            TSLog.e(TAG, "startLoginInteractive() failed: ${it.message}")
+                            completionHandler(Result.failure(it))
+                          }
+                          .onSuccess { completionHandler(Result.success(Unit)) }
                     }
-
-    val startAction = {
-      Client(viewModelScope).start(Ipn.Options(AuthKey = authKey)) { start ->
-        start.onFailure { completionHandler(Result.failure(it)) }.onSuccess { stopThenLogin() }
                   }
             }
-
-    // If an MDM control URL is set, we will always use that in lieu of anything the user sets.
-    var prefs = maskedPrefs
-    val mdmControlURL = MDMSettings.loginURL.flow.value.value
-
-    if (mdmControlURL != null) {
-      prefs = prefs ?: Ipn.MaskedPrefs()
-      prefs.ControlURL = mdmControlURL
-      TSLog.d(TAG, "Overriding control URL with MDM value: $mdmControlURL")
           }
-
-    prefs?.let {
-      Client(viewModelScope).editPrefs(it) { result ->
-        result.onFailure { completionHandler(Result.failure(it)) }.onSuccess { startAction() }
     }
-    } ?: run { startAction() }
   }
 
   fun loginWithAuthKey(authKey: String, completionHandler: (Result<Unit>) -> Unit = {}) {