Proposal: deprecate autovalidate parameter of the Form, FormField and TextFormField widget (#61648)

dev/integration_tests/flutter_gallery/lib/demo/material/text_form_field_demo.dart

@@ -95,7 +95,7 @@ class TextFormFieldDemoState extends State<TextFormFieldDemo> {
     ));
   }
 
-  bool _autovalidate = false;
+  AutovalidateMode _autovalidateMode = AutovalidateMode.disabled;
   bool _formWasEdited = false;
 
   final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
@@ -104,7 +104,7 @@ class TextFormFieldDemoState extends State<TextFormFieldDemo> {
   void _handleSubmitted() {
     final FormState form = _formKey.currentState;
     if (!form.validate()) {
-      _autovalidate = true; // Start validating on every change.
+      _autovalidateMode = AutovalidateMode.always; // Start validating on every change.
       showInSnackBar('Please fix the errors in red before submitting.');
     } else {
       form.save();
@@ -180,7 +180,7 @@ class TextFormFieldDemoState extends State<TextFormFieldDemo> {
         bottom: false,
         child: Form(
           key: _formKey,
-          autovalidate: _autovalidate,
+          autovalidateMode: _autovalidateMode,
           onWillPop: _warnUserAboutInvalidData,
           child: Scrollbar(
             child: SingleChildScrollView(

packages/flutter/lib/src/material/dropdown.dart

@@ -1468,6 +1468,11 @@ class DropdownButtonFormField<T> extends FormField<T> {
     InputDecoration decoration,
     FormFieldSetter<T> onSaved,
     FormFieldValidator<T> validator,
+    @Deprecated(
+      'Use autoValidateMode parameter which provide more specific '
+      'behaviour related to auto validation. '
+      'This feature was deprecated after v1.19.0.'
+    )
     bool autovalidate = false,
     AutovalidateMode autovalidateMode,
   }) : assert(items == null || items.isEmpty || value == null ||

packages/flutter/lib/src/material/text_form_field.dart

@@ -88,7 +88,7 @@ export 'package:flutter/services.dart' show SmartQuotesType, SmartDashesType;
 ///         },
 ///         child: FocusTraversalGroup(
 ///           child: Form(
-///             autovalidate: true,
+///             autovalidateMode: AutovalidateMode.always,
 ///             onChanged: () {
 ///               Form.of(primaryFocus.context).save();
 ///             },
@@ -158,6 +158,11 @@ class TextFormField extends FormField<String> {
     SmartDashesType smartDashesType,
     SmartQuotesType smartQuotesType,
     bool enableSuggestions = true,
+    @Deprecated(
+      'Use autoValidateMode parameter which provide more specific '
+      'behaviour related to auto validation. '
+      'This feature was deprecated after v1.19.0.'
+    )
     bool autovalidate = false,
     bool maxLengthEnforced = true,
     int maxLines = 1,

packages/flutter/lib/src/widgets/form.dart

@@ -78,7 +78,12 @@ class Form extends StatefulWidget {
   const Form({
     Key key,
     @required this.child,
-    this.autovalidate = false,
+    @Deprecated(
+      'Use autoValidateMode parameter which provide more specific '
+      'behaviour related to auto validation. '
+      'This feature was deprecated after v1.19.0.'
+    )
+    bool autovalidate = false,
     this.onWillPop,
     this.onChanged,
     AutovalidateMode autovalidateMode,
@@ -114,11 +119,6 @@ class Form extends StatefulWidget {
   /// {@macro flutter.widgets.child}
   final Widget child;
 
-  /// If true, form fields will validate and update their error text
-  /// immediately after every change. Otherwise, you must call
-  /// [FormState.validate] to validate.
-  final bool autovalidate;
-
   /// Enables the form to veto attempts by the user to dismiss the [ModalRoute]
   /// that contains the form.
   ///
@@ -319,7 +319,12 @@ class FormField<T> extends StatefulWidget {
     this.onSaved,
     this.validator,
     this.initialValue,
-    this.autovalidate = false,
+    @Deprecated(
+      'Use autoValidateMode parameter which provide more specific '
+      'behaviour related to auto validation. '
+      'This feature was deprecated after v1.19.0.'
+    )
+    bool autovalidate = false,
     this.enabled = true,
     AutovalidateMode autovalidateMode,
   }) : assert(builder != null),
@@ -360,12 +365,6 @@ class FormField<T> extends StatefulWidget {
   /// An optional value to initialize the form field to, or null otherwise.
   final T initialValue;
 
-  /// If true, this form field will validate and update its error text
-  /// immediately after every change. Otherwise, you must call
-  /// [FormFieldState.validate] to validate. If part of a [Form] that
-  /// auto-validates, this value will be ignored.
-  final bool autovalidate;
-
   /// Whether the form is able to receive user input.
   ///
   /// Defaults to true. If [autovalidateMode] is not [AutovalidateMode.disabled],
@@ -382,8 +381,8 @@ class FormField<T> extends StatefulWidget {
   /// will auto validate even without user interaction and
   /// if [AutovalidateMode.disabled] the auto validation will be disabled.
   ///
-  /// Defaults to [AutovalidateMode.disabled] if [autovalidate] is false which
-  /// means no auto validation will occur. If [autovalidate] is true then this
+  /// Defaults to [AutovalidateMode.disabled] if `autovalidate` is false which
+  /// means no auto validation will occur. If `autovalidate` is true then this
   /// is set to [AutovalidateMode.always] for backward compatibility.
   /// {@endtemplate}
   final AutovalidateMode autovalidateMode;