Fix for errors on a non scrollable editor (580) (#620)

lib/src/widgets/editor.dart

@@ -721,6 +721,7 @@ class RenderEditor extends RenderEditableContainerBox
     required TextDirection textDirection,
     required bool hasFocus,
     required this.selection,
+    required this.scrollable,
     required LayerLink startHandleLayerLink,
     required LayerLink endHandleLayerLink,
     required EdgeInsetsGeometry padding,
@@ -750,6 +751,7 @@ class RenderEditor extends RenderEditableContainerBox
 
   final CursorCont _cursorController;
   final bool floatingCursorDisabled;
+  final bool scrollable;
 
   Document document;
   TextSelection selection;
@@ -1125,17 +1127,18 @@ class RenderEditor extends RenderEditableContainerBox
   @override
   void performLayout() {
     assert(() {
-      if (!constraints.hasBoundedHeight) return true;
+      if (!scrollable || !constraints.hasBoundedHeight) return true;
       throw FlutterError.fromParts(<DiagnosticsNode>[
         ErrorSummary('RenderEditableContainerBox must have '
-            'unlimited space along its main axis.'),
+            'unlimited space along its main axis when it is scrollable.'),
         ErrorDescription('RenderEditableContainerBox does not clip or'
             ' resize its children, so it must be '
             'placed in a parent that does not constrain the main '
             'axis.'),
         ErrorHint(
             'You probably want to put the RenderEditableContainerBox inside a '
-            'RenderViewport with a matching main axis.')
+            'RenderViewport with a matching main axis or disable the '
+            'scrollable property.')
       ]);
     }());
     assert(() {

lib/src/widgets/raw_editor.dart

@@ -295,6 +295,7 @@ class RawEditorState extends EditorState
           document: _doc,
           selection: widget.controller.selection,
           hasFocus: _hasFocus,
+          scrollable: widget.scrollable,
           cursorController: _cursorCont,
           textDirection: _textDirection,
           startHandleLayerLink: _startHandleLayerLink,
@@ -333,6 +334,7 @@ class RawEditorState extends EditorState
               document: _doc,
               selection: widget.controller.selection,
               hasFocus: _hasFocus,
+              scrollable: widget.scrollable,
               textDirection: _textDirection,
               startHandleLayerLink: _startHandleLayerLink,
               endHandleLayerLink: _endHandleLayerLink,
@@ -934,6 +936,7 @@ class _Editor extends MultiChildRenderObjectWidget {
     required this.document,
     required this.textDirection,
     required this.hasFocus,
+    required this.scrollable,
     required this.selection,
     required this.startHandleLayerLink,
     required this.endHandleLayerLink,
@@ -951,6 +954,7 @@ class _Editor extends MultiChildRenderObjectWidget {
   final Document document;
   final TextDirection textDirection;
   final bool hasFocus;
+  final bool scrollable;
   final TextSelection selection;
   final LayerLink startHandleLayerLink;
   final LayerLink endHandleLayerLink;
@@ -969,6 +973,7 @@ class _Editor extends MultiChildRenderObjectWidget {
         document: document,
         textDirection: textDirection,
         hasFocus: hasFocus,
+        scrollable: scrollable,
         selection: selection,
         startHandleLayerLink: startHandleLayerLink,
         endHandleLayerLink: endHandleLayerLink,

lib/src/widgets/raw_editor/raw_editor_state_selection_delegate_mixin.dart

@@ -63,7 +63,9 @@ mixin RawEditorStateSelectionDelegateMixin on EditorState
     final localRect = renderEditor.getLocalRectForCaret(position);
     final targetOffset = _getOffsetToRevealCaret(localRect, position);
 
-    scrollController.jumpTo(targetOffset.offset);
+    if (scrollController.hasClients) {
+      scrollController.jumpTo(targetOffset.offset);
+    }
     renderEditor.showOnScreen(rect: targetOffset.rect);
   }
 
@@ -77,7 +79,9 @@ mixin RawEditorStateSelectionDelegateMixin on EditorState
   // `renderEditable.preferredLineHeight`, before the target scroll offset is
   // calculated.
   RevealedOffset _getOffsetToRevealCaret(Rect rect, TextPosition position) {
-    if (!scrollController.position.allowImplicitScrolling) {
+    // Make sure scrollController is attached
+    if (scrollController.hasClients &&
+        !scrollController.position.allowImplicitScrolling) {
       return RevealedOffset(offset: scrollController.offset, rect: rect);
     }
 
@@ -102,12 +106,17 @@ mixin RawEditorStateSelectionDelegateMixin on EditorState
 
     // No overscrolling when encountering tall fonts/scripts that extend past
     // the ascent.
-    final targetOffset = (additionalOffset + scrollController.offset).clamp(
-      scrollController.position.minScrollExtent,
-      scrollController.position.maxScrollExtent,
-    );
+    var targetOffset = additionalOffset;
+    if (scrollController.hasClients) {
+      targetOffset = (additionalOffset + scrollController.offset).clamp(
+        scrollController.position.minScrollExtent,
+        scrollController.position.maxScrollExtent,
+      );
+    }
 
-    final offsetDelta = scrollController.offset - targetOffset;
+    final offsetDelta =
+        (scrollController.hasClients ? scrollController.offset : 0) -
+            targetOffset;
     return RevealedOffset(
         rect: rect.shift(unitOffset * offsetDelta), offset: targetOffset);
   }