refactor(tabs): split TabsNavState into state and update request

Mirrors the iOS split landed in PR #3950. `TabsNavState` previously
served as both the authoritative current state and the JS-driven update
request, with `provenance` doing double duty as both "current generation"
and "base provenance the request was derived from". Splits out
`TabsNavStateUpdateRequest(selectedScreenKey, baseProvenance,
actionOrigin)` as a sibling type.

Origin assignment moves from the container to the request-construction
site (`TabsHostViewManager.setNavStateRequest`). The container becomes
origin-agnostic on the JS-driven path: `onMenuItemSelected` reads
`actionOrigin` off the buffered `TabSelectOp.request` instead of
hardcoding `PROGRAMMATIC_JS`. Today only `PROGRAMMATIC_JS` flows through,
so runtime behavior is unchanged — but future native-programmatic
origins can land here without touching the container.

Also bundles a `TabsNavState.selectedKey -> selectedScreenKey` rename
for consistency with the JS contract and the new request type. JS-facing
WritableMap keys (`selectedScreenKey`, `rejectedScreenKey`) were already
named correctly; this only aligns the Kotlin-internal field name.

Author: kkafar

android/src/main/java/com/swmansion/rnscreens/gamma/tabs/container/TabsContainer.kt

@@ -77,7 +77,7 @@ internal class TabsContainer(
 
     internal val selectedTab: TabsScreenFragment
         get() =
-            checkNotNull(getFragmentForScreenKey(navState.selectedKey)) { "[RNScreens] No selected tab present" }
+            checkNotNull(getFragmentForScreenKey(navState.selectedScreenKey)) { "[RNScreens] No selected tab present" }
 
     internal val invalidationFlags = TabsContainerInvalidationFlags()
 
@@ -259,14 +259,14 @@ internal class TabsContainer(
         val tabSelectOp = pendingOperation as TabSelectOp
 
         val nextSelectedMenuItemId =
-            checkNotNull(getMenuItemIdForFragment(requireFragmentForScreenKey(tabSelectOp.navState.selectedKey))) {
-                "[RNScreens] Failed to find Menu Item for screenKey: ${tabSelectOp.navState.selectedKey}"
+            checkNotNull(getMenuItemIdForFragment(requireFragmentForScreenKey(tabSelectOp.request.selectedScreenKey))) {
+                "[RNScreens] Failed to find Menu Item for screenKey: ${tabSelectOp.request.selectedScreenKey}"
             }
 
-        if (rejectOpsWithStaleNavState && isNavStateStale(tabSelectOp.navState)) {
+        if (rejectOpsWithStaleNavState && isNavStateStale(tabSelectOp.request)) {
             delegate.onNavStateUpdateRejected(
                 navState,
-                tabSelectOp.navState,
+                tabSelectOp.request,
                 TabsNavStateUpdateRejectionReason.STALE,
             )
             pendingOperation = null
@@ -281,7 +281,7 @@ internal class TabsContainer(
         } else {
             delegate.onNavStateUpdateRejected(
                 navState,
-                tabSelectOp.navState,
+                tabSelectOp.request,
                 TabsNavStateUpdateRejectionReason.REPEATED,
             )
         }
@@ -328,7 +328,7 @@ internal class TabsContainer(
         val currentSelectedFragment = selectedTab
 
         if (nextSelectedFragment === currentSelectedFragment) {
-            progressNavigationState(navState.selectedKey)
+            progressNavigationState(navState.selectedScreenKey)
             return true
         }
 
@@ -343,8 +343,8 @@ internal class TabsContainer(
         return true
     }
 
-    private fun progressNavigationState(selectedKey: String) {
-        navState = TabsNavState(selectedKey, navState.provenance + 1)
+    private fun progressNavigationState(selectedScreenKey: String) {
+        navState = TabsNavState(selectedScreenKey, navState.provenance + 1)
         if (!isInExternalOperationContext) {
             lastUINavState = navState
         }
@@ -377,7 +377,12 @@ internal class TabsContainer(
                 navState,
                 isRepeated = isRepeated,
                 hasTriggeredSpecialEffect = hasTriggeredSpecialEffect,
-                actionOrigin = if (isInExternalOperationContext) TabsActionOrigin.PROGRAMMATIC_JS else TabsActionOrigin.USER,
+                actionOrigin =
+                    if (isInExternalOperationContext) {
+                        (pendingOperation as TabSelectOp).request.actionOrigin
+                    } else {
+                        TabsActionOrigin.USER
+                    },
             )
         }
 
@@ -413,7 +418,7 @@ internal class TabsContainer(
 
     private fun getSelectedTabsScreenFragmentId(): Int? =
         tabsModel
-            .indexOfFirst { it.requireScreenKey == navState.selectedKey }
+            .indexOfFirst { it.requireScreenKey == navState.selectedScreenKey }
             .takeIf { it != -1 }
 
     private fun getMenuItemForTabsScreen(tabsScreen: TabsScreen): MenuItem? =
@@ -544,9 +549,9 @@ internal class TabsContainer(
         fragmentManager = null
     }
 
-    private fun isNavStateStale(state: TabsNavState): Boolean {
+    private fun isNavStateStale(request: TabsNavStateUpdateRequest): Boolean {
         if (navState.isEmpty() || lastUINavState.isEmpty()) return false
-        return state.provenance < lastUINavState.provenance
+        return request.baseProvenance < lastUINavState.provenance
     }
 
     companion object {

android/src/main/java/com/swmansion/rnscreens/gamma/tabs/container/TabsContainerDelegate.kt

@@ -24,12 +24,12 @@ internal interface TabsContainerDelegate {
      * Called when the container rejects a navigation state update.
      *
      * @param currentNavState The currently active navigation state that was kept.
-     * @param rejectedNavState The navigation state update that was rejected.
+     * @param rejectedRequest The navigation state update request that was rejected.
      * @param reason Why the update was rejected.
      */
     fun onNavStateUpdateRejected(
         currentNavState: TabsNavState,
-        rejectedNavState: TabsNavState,
+        rejectedRequest: TabsNavStateUpdateRequest,
         reason: TabsNavStateUpdateRejectionReason,
     )
 

android/src/main/java/com/swmansion/rnscreens/gamma/tabs/container/TabsContainerOps.kt

@@ -3,5 +3,5 @@ package com.swmansion.rnscreens.gamma.tabs.container
 internal sealed class TabsContainerOp
 
 internal data class TabSelectOp(
-    val navState: TabsNavState,
+    val request: TabsNavStateUpdateRequest,
 ) : TabsContainerOp()

android/src/main/java/com/swmansion/rnscreens/gamma/tabs/container/TabsNavState.kt

@@ -6,13 +6,13 @@ import com.swmansion.rnscreens.gamma.tabs.container.TabsNavStateUpdateRejectionR
 /**
  * Describes navigation state of a tabs container.
  *
- * @property selectedKey Screen key of the currently selected tab.
+ * @property selectedScreenKey Screen key of the currently selected tab.
  * @property provenance Monotonically increasing number describing the history (generation) of the state.
  *   State with provenance `N + 1` is derived from state with provenance `N`.
  *   This allows detecting stale updates.
  */
 data class TabsNavState(
-    val selectedKey: String,
+    val selectedScreenKey: String,
     val provenance: Int,
 ) {
     internal fun isEmpty(): Boolean = this === EMPTY
@@ -24,6 +24,23 @@ data class TabsNavState(
     }
 }
 
+/**
+ * A request to change navigation state.
+ *
+ * Carries the target [selectedScreenKey], the [baseProvenance] of the state the request was derived from,
+ * and the [actionOrigin] (actor) that initiated it. Mirrors the public `TabsHostNavStateRequest` TS type
+ * plus an [actionOrigin] carried internally.
+ *
+ * @property selectedScreenKey Screen key of the requested tab.
+ * @property baseProvenance Provenance of the state this request was derived from. Used for staleness detection.
+ * @property actionOrigin Origin (actor) that initiated this request.
+ */
+data class TabsNavStateUpdateRequest(
+    val selectedScreenKey: String,
+    val baseProvenance: Int,
+    val actionOrigin: TabsActionOrigin,
+)
+
 /**
  * Reason why a navigation state update was rejected by the container.
  *

android/src/main/java/com/swmansion/rnscreens/gamma/tabs/host/TabsHost.kt

@@ -18,6 +18,7 @@ import com.swmansion.rnscreens.gamma.tabs.container.TabsContainer
 import com.swmansion.rnscreens.gamma.tabs.container.TabsContainerDelegate
 import com.swmansion.rnscreens.gamma.tabs.container.TabsNavState
 import com.swmansion.rnscreens.gamma.tabs.container.TabsNavStateUpdateRejectionReason
+import com.swmansion.rnscreens.gamma.tabs.container.TabsNavStateUpdateRequest
 import com.swmansion.rnscreens.gamma.tabs.screen.TabsScreen
 import com.swmansion.rnscreens.utils.RNSLog
 import kotlin.properties.Delegates
@@ -30,7 +31,7 @@ class TabsHost(
     TabsContainerDelegate,
     UIManagerListener {
     private val renderedScreens: ArrayList<TabsScreen> = arrayListOf()
-    private var jsNavStateRequest: TabsNavState = TabsNavState.EMPTY
+    private var jsNavStateRequest: TabsNavStateUpdateRequest? = null
 
     private val container: TabsContainer =
         TabsContainer(reactContext, this).apply {
@@ -110,9 +111,9 @@ class TabsHost(
         container.removeAllTabsScreens()
     }
 
-    internal fun updateJSNavStateRequest(navStateRequest: TabsNavState) {
+    internal fun updateJSNavStateRequest(navStateRequest: TabsNavStateUpdateRequest) {
         jsNavStateRequest = navStateRequest
-        container.setContainerOperation(TabSelectOp(jsNavStateRequest.copy()))
+        container.setContainerOperation(TabSelectOp(navStateRequest.copy()))
     }
 
     private val layoutCallback =
@@ -163,7 +164,7 @@ class TabsHost(
         actionOrigin: TabsActionOrigin,
     ) {
         eventEmitter.emitOnTabSelectedEvent(
-            navState.selectedKey,
+            navState.selectedScreenKey,
             navState.provenance,
             isRepeated,
             hasTriggeredSpecialEffect,
@@ -173,12 +174,12 @@ class TabsHost(
 
     override fun onNavStateUpdateRejected(
         currentNavState: TabsNavState,
-        rejectedNavState: TabsNavState,
+        rejectedRequest: TabsNavStateUpdateRequest,
         reason: TabsNavStateUpdateRejectionReason,
     ) {
         eventEmitter.emitOnTabSelectionRejectedEvent(
             currentNavState,
-            rejectedNavState,
+            rejectedRequest,
             reason,
         )
     }

android/src/main/java/com/swmansion/rnscreens/gamma/tabs/host/TabsHostEventEmitter.kt

@@ -5,6 +5,7 @@ import com.swmansion.rnscreens.gamma.common.event.BaseEventEmitter
 import com.swmansion.rnscreens.gamma.tabs.container.TabsActionOrigin
 import com.swmansion.rnscreens.gamma.tabs.container.TabsNavState
 import com.swmansion.rnscreens.gamma.tabs.container.TabsNavStateUpdateRejectionReason
+import com.swmansion.rnscreens.gamma.tabs.container.TabsNavStateUpdateRequest
 import com.swmansion.rnscreens.gamma.tabs.host.event.TabsHostTabSelectedEvent
 import com.swmansion.rnscreens.gamma.tabs.host.event.TabsHostTabSelectionPreventedEvent
 import com.swmansion.rnscreens.gamma.tabs.host.event.TabsHostTabSelectionRejectedEvent
@@ -42,15 +43,15 @@ internal class TabsHostEventEmitter(
      */
     fun emitOnTabSelectionRejectedEvent(
         currentNavState: TabsNavState,
-        rejectedNavState: TabsNavState,
+        rejectedRequest: TabsNavStateUpdateRequest,
         rejectionReason: TabsNavStateUpdateRejectionReason,
     ) {
         reactEventDispatcher.dispatchEvent(
             TabsHostTabSelectionRejectedEvent(
                 surfaceId,
                 viewTag,
                 currentNavState,
-                rejectedNavState,
+                rejectedRequest,
                 rejectionReason,
             ),
         )

android/src/main/java/com/swmansion/rnscreens/gamma/tabs/host/TabsHostViewManager.kt

@@ -11,7 +11,8 @@ import com.facebook.react.viewmanagers.RNSTabsHostAndroidManagerDelegate
 import com.facebook.react.viewmanagers.RNSTabsHostAndroidManagerInterface
 import com.swmansion.rnscreens.gamma.common.colorscheme.ColorScheme
 import com.swmansion.rnscreens.gamma.helpers.makeEventRegistrationInfo
-import com.swmansion.rnscreens.gamma.tabs.container.TabsNavState
+import com.swmansion.rnscreens.gamma.tabs.container.TabsActionOrigin
+import com.swmansion.rnscreens.gamma.tabs.container.TabsNavStateUpdateRequest
 import com.swmansion.rnscreens.gamma.tabs.host.event.TabsHostTabSelectedEvent
 import com.swmansion.rnscreens.gamma.tabs.host.event.TabsHostTabSelectionPreventedEvent
 import com.swmansion.rnscreens.gamma.tabs.host.event.TabsHostTabSelectionRejectedEvent
@@ -79,7 +80,13 @@ class TabsHostViewManager :
         val navStateRequestMap = requireNotNull(value) { "[RNScreens] navStateRequest must not be nullish" }
         val selectedScreenKey = requireNotNull(navStateRequestMap.getString("selectedScreenKey"))
         val baseProvenance = requireNotNull(navStateRequestMap.getInt("baseProvenance"))
-        view.updateJSNavStateRequest(TabsNavState(selectedScreenKey, baseProvenance))
+        view.updateJSNavStateRequest(
+            TabsNavStateUpdateRequest(
+                selectedScreenKey = selectedScreenKey,
+                baseProvenance = baseProvenance,
+                actionOrigin = TabsActionOrigin.PROGRAMMATIC_JS,
+            ),
+        )
     }
 
     override fun setRejectStaleNavStateUpdates(

android/src/main/java/com/swmansion/rnscreens/gamma/tabs/host/event/TabsHostTabSelectionPreventedEvent.kt

@@ -27,7 +27,7 @@ class TabsHostTabSelectionPreventedEvent(
 
     override fun getEventData(): WritableMap? =
         Arguments.createMap().apply {
-            putString(EK_SELECTED_KEY, currentNavState.selectedKey)
+            putString(EK_SELECTED_KEY, currentNavState.selectedScreenKey)
             putInt(EK_PROVENANCE, currentNavState.provenance)
             putString(EK_PREVENTED_KEY, preventedScreenKey)
         }

android/src/main/java/com/swmansion/rnscreens/gamma/tabs/host/event/TabsHostTabSelectionRejectedEvent.kt

@@ -6,19 +6,20 @@ import com.facebook.react.uimanager.events.Event
 import com.swmansion.rnscreens.gamma.common.event.NamingAwareEventType
 import com.swmansion.rnscreens.gamma.tabs.container.TabsNavState
 import com.swmansion.rnscreens.gamma.tabs.container.TabsNavStateUpdateRejectionReason
+import com.swmansion.rnscreens.gamma.tabs.container.TabsNavStateUpdateRequest
 
 /**
  * React Native event dispatched to JS when a tab selection request is rejected by the container.
  *
- * Carries the currently active navigation state ([currentNavState]), the rejected update
- * ([rejectedNavState]), and the [rejectionReason]. This event is never coalesced — every
+ * Carries the currently active navigation state ([currentNavState]), the rejected request
+ * ([rejectedRequest]), and the [rejectionReason]. This event is never coalesced — every
  * rejection is delivered individually so the JS side has a complete picture of state transitions.
  */
 class TabsHostTabSelectionRejectedEvent(
     surfaceId: Int,
     viewId: Int,
     val currentNavState: TabsNavState,
-    val rejectedNavState: TabsNavState,
+    val rejectedRequest: TabsNavStateUpdateRequest,
     val rejectionReason: TabsNavStateUpdateRejectionReason,
 ) : Event<TabsHostTabSelectionRejectedEvent>(surfaceId, viewId),
     NamingAwareEventType {
@@ -31,10 +32,10 @@ class TabsHostTabSelectionRejectedEvent(
 
     override fun getEventData(): WritableMap? =
         Arguments.createMap().apply {
-            putString(EK_SELECTED_KEY, currentNavState.selectedKey)
+            putString(EK_SELECTED_KEY, currentNavState.selectedScreenKey)
             putInt(EK_PROVENANCE, currentNavState.provenance)
-            putString(EK_REJECTED_KEY, rejectedNavState.selectedKey)
-            putInt(EK_REJECTED_PROVENANCE, rejectedNavState.provenance)
+            putString(EK_REJECTED_KEY, rejectedRequest.selectedScreenKey)
+            putInt(EK_REJECTED_PROVENANCE, rejectedRequest.baseProvenance)
             putString(EK_REJECTION_REASON, rejectionReason.toString())
         }