ADFA-3133 Bug fix for over-eager auto-save during onPause event

app/src/main/AndroidManifest.xml

@@ -93,7 +93,7 @@
             android:theme="@style/Theme.AndroidIDE" />
         <activity
             android:name=".activities.editor.EditorActivityKt"
-            android:configChanges="orientation|screenSize|screenLayout|smallestScreenSize"
+            android:configChanges="orientation|screenSize|screenLayout|smallestScreenSize|fontScale|density|uiMode"
             android:launchMode="singleTask"
             android:windowSoftInputMode="adjustResize" />
         <activity

app/src/main/java/com/itsaky/androidide/activities/editor/EditorHandlerActivity.kt

@@ -232,6 +232,10 @@ open class EditorHandlerActivity :
 		loadPluginTabs()
 	}
 
+	/**
+	 * Persists which tabs are open (preferences only). Does **not** write project file buffers to disk;
+	 * saving is explicit or prompted (e.g. close project).
+	 */
 	override fun onPause() {
 		super.onPause()
 		// Record timestamps for all currently open files before saving the cache
@@ -246,7 +250,6 @@ open class EditorHandlerActivity :
 		if (!isOpenedFilesSaved.get()) {
 			saveOpenedFiles()
 			saveOpenedPluginTabs()
-			saveAllAsync(notify = false)
 		}
 	}
 
@@ -271,26 +274,31 @@ open class EditorHandlerActivity :
 		invalidateOptionsMenu()
 	}
 
+	/**
+	 * Reloads disk content into an open editor only when the file changed on disk since the last
+	 * [onPause] snapshot **and** the in-memory buffer is still clean ([CodeEditorView.isModified] is
+	 * false). Never replaces buffers with unsaved edits or touches undo history for dirty files.
+	 */
 	private fun checkForExternalFileChanges() {
-		// Get the list of files currently managed by the ViewModel
 		val openFiles = editorViewModel.getOpenedFiles()
 		if (openFiles.isEmpty() || fileTimestamps.isEmpty()) return
 
 		lifecycleScope.launch(Dispatchers.IO) {
-			// Check each open file
 			openFiles.forEach { file ->
 				val lastKnownTimestamp = fileTimestamps[file.absolutePath] ?: return@forEach
 				val currentTimestamp = file.lastModified()
 
-				// If the file on disk is newer.
 				if (currentTimestamp > lastKnownTimestamp) {
 					val newContent = runCatching { file.readText() }.getOrNull() ?: return@forEach
 					withContext(Dispatchers.Main) {
-						// If the editor for the new file exists AND has no unsaved changes...
 						val editorView = getEditorForFile(file) ?: return@withContext
 						if (editorView.isModified) return@withContext
+						val ideEditor = editorView.editor ?: return@withContext
+						if (ideEditor.canUndo() || ideEditor.canRedo()) {
+							return@withContext
+						}
 
-						editorView.editor?.setText(newContent)
+						ideEditor.setText(newContent)
 						editorView.markAsSaved()
 						updateTabs()
 					}
@@ -341,12 +349,19 @@ open class EditorHandlerActivity :
 					prefs.getString(PREF_KEY_OPEN_FILES_CACHE, null)
 				} ?: return@launch
 
+				if (editorViewModel.getOpenedFileCount() > 0) {
+					// Returning to an in-memory session (e.g. after onPause/onStop). Replaying the
+					// snapshot would be redundant and could interfere with dirty buffers and undo.
+					withContext(Dispatchers.IO) { prefs.putString(PREF_KEY_OPEN_FILES_CACHE, null) }
+					return@launch
+				}
+
 				val cache = withContext(Dispatchers.Default) {
 					Gson().fromJson(jsonCache, OpenedFilesCache::class.java)
 				}
 				onReadOpenedFilesCache(cache)
 
-				// Clear the preference so it's only loaded once on startup
+				// Clear the preference so it's only loaded once per cold restore
 				withContext(Dispatchers.IO) { prefs.putString(PREF_KEY_OPEN_FILES_CACHE, null) }
 			} catch (err: Throwable) {
 				log.error("Failed to reopen recently opened files", err)
@@ -747,6 +762,11 @@ open class EditorHandlerActivity :
 	override fun onConfigurationChanged(newConfig: Configuration) {
 		super.onConfigurationChanged(newConfig)
 
+		val safeContent = contentOrNull ?: return
+		for (i in 0 until safeContent.editorContainer.childCount) {
+			(safeContent.editorContainer.getChildAt(i) as? CodeEditorView)?.reapplyEditorDisplayPreferences()
+		}
+
 		getCurrentEditor()?.editor?.apply {
 			doOnNextLayout {
 				cursor?.let { c -> ensurePositionVisible(c.leftLine, c.leftColumn, true) }
@@ -1069,17 +1089,20 @@ open class EditorHandlerActivity :
 				nameBuilder.addPath(it, it.path)
 			}
 
-			for (index in 0 until content.tabs.tabCount) {
-				val file = files.getOrNull(index) ?: continue
+			for (tabPos in 0 until content.tabs.tabCount) {
+				if (isPluginTab(tabPos)) continue
+				val fileIndex = getFileIndexForTabPosition(tabPos)
+				if (fileIndex < 0) continue
+				val file = files.getOrNull(fileIndex) ?: continue
 				val count = dupliCount[file.name] ?: 0
 
-				val isModified = getEditorAtIndex(index)?.isModified ?: false
+				val isModified = getEditorAtIndex(fileIndex)?.isModified ?: false
 				var name = if (count > 1) nameBuilder.getShortPath(file) else file.name
 				if (isModified) {
 					name = "*$name"
 				}
 
-				names[index] = name to FileExtension.Factory.forFile(file, file.isDirectory).icon
+				names[tabPos] = name to FileExtension.Factory.forFile(file, file.isDirectory).icon
 			}
 
 			withContext(Dispatchers.Main) {

app/src/main/java/com/itsaky/androidide/fragments/RecyclerViewFragment.kt

@@ -20,12 +20,15 @@ package com.itsaky.androidide.fragments
 import android.annotation.SuppressLint
 import android.os.Bundle
 import android.view.GestureDetector
+import android.view.LayoutInflater
 import android.view.MotionEvent
 import android.view.View
+import android.view.ViewGroup
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import androidx.recyclerview.widget.RecyclerView.LayoutManager
-import com.itsaky.androidide.databinding.FragmentRecyclerviewBinding
+import androidx.viewbinding.ViewBinding
+import com.itsaky.androidide.R
 import com.itsaky.androidide.idetooltips.TooltipManager
 
 /**
@@ -34,7 +37,7 @@ import com.itsaky.androidide.idetooltips.TooltipManager
  * @author Akash Yadav
  */
 abstract class RecyclerViewFragment<A : RecyclerView.Adapter<*>> :
-	EmptyStateFragment<FragmentRecyclerviewBinding>(FragmentRecyclerviewBinding::inflate) {
+	EmptyStateFragment<FragmentRecyclerviewManualBinding>(FragmentRecyclerviewManualBinding::inflate) {
 	protected abstract val fragmentTooltipTag: String?
 
 	private var unsavedAdapter: A? = null
@@ -86,7 +89,7 @@ abstract class RecyclerViewFragment<A : RecyclerView.Adapter<*>> :
 	 * Sets up the recycler view in the fragment.
 	 */
 	protected open fun onSetupRecyclerView() {
-		binding.root.apply {
+		binding.list.apply {
 			layoutManager = onCreateLayoutManager()
 			adapter = unsavedAdapter ?: onCreateAdapter()
 		}
@@ -107,7 +110,7 @@ abstract class RecyclerViewFragment<A : RecyclerView.Adapter<*>> :
 
 		onSetupRecyclerView()
 
-		binding.root.addOnItemTouchListener(touchListener)
+		binding.list.addOnItemTouchListener(touchListener)
 
 		unsavedAdapter = null
 
@@ -123,7 +126,7 @@ abstract class RecyclerViewFragment<A : RecyclerView.Adapter<*>> :
 	 * Set the adapter for the [RecyclerView].
 	 */
 	fun setAdapter(adapter: A) {
-		_binding?.root?.let { list -> list.adapter = adapter } ?: run { unsavedAdapter = adapter }
+		_binding?.list?.let { list -> list.adapter = adapter } ?: run { unsavedAdapter = adapter }
         if (isAdded && view != null) {
             checkIsEmpty()
         }
@@ -142,6 +145,33 @@ abstract class RecyclerViewFragment<A : RecyclerView.Adapter<*>> :
 
 	private fun checkIsEmpty() {
         if (!isAdded || isDetached) return
-        isEmpty = _binding?.root?.adapter?.itemCount == 0
+        isEmpty = _binding?.list?.adapter?.itemCount == 0
+	}
+}
+
+/**
+ * Manual [ViewBinding] for [R.layout.fragment_recyclerview] so annotation processors (kapt) do not
+ * depend on generated `FragmentRecyclerviewBinding` during stub analysis.
+ *
+ * Public (not internal/file-private): [RecyclerViewFragment] is public and Kotlin forbids a public
+ * class from using a non-public type as a [EmptyStateFragment] type argument.
+ *
+ * [getRoot] returns [RecyclerView] (covariant override), matching generated view binding so
+ * subclasses can use `binding.root.adapter` and other [RecyclerView] APIs.
+ */
+class FragmentRecyclerviewManualBinding(
+	val list: RecyclerView,
+) : ViewBinding {
+	override fun getRoot(): RecyclerView = list
+
+	companion object {
+		fun inflate(
+			inflater: LayoutInflater,
+			parent: ViewGroup?,
+			attachToParent: Boolean,
+		): FragmentRecyclerviewManualBinding {
+			val root = inflater.inflate(R.layout.fragment_recyclerview, parent, false) as RecyclerView
+			return FragmentRecyclerviewManualBinding(root)
+		}
 	}
 }

app/src/main/java/com/itsaky/androidide/ui/CodeEditorView.kt

@@ -567,6 +567,15 @@ class CodeEditorView(
 		onPinLineNumbersPrefChanged()
 	}
 
+	/**
+	 * Re-applies display-related preferences (font size, typeface, flags) after a configuration change
+	 * such as system font scale, so the editor activity can handle `fontScale` without being recreated.
+	 */
+	fun reapplyEditorDisplayPreferences() {
+		if (_binding == null) return
+		configureEditorIfNeeded()
+	}
+
 	private fun onMagnifierPrefChanged() {
 		binding.editor.getComponent(Magnifier::class.java).isEnabled =
 			EditorPreferences.useMagnifier