Form: standalone HTTP processing split into new StandaloneForm (BC break)

Form is now a detached base: it builds, validates and renders, but has
no access to submitted data (isAnchored() returns false, submission API
throws InvalidStateException pointing to StandaloneForm).

StandaloneForm extends Form and carries the standalone mechanics moved
from Form: $httpRequest, static initialize(), receiveHttpData() with
method/Sec-Fetch/tracker checks, the hidden '_form_' tracker and the
TrackerId constant. Form::initialize() is removed.

The base receiveHttpData() throws, making the isAnchored()/
receiveHttpData() pair contract loud in both directions. Descendants
providing their own source of submitted data must override both
(Nette\Application\UI\Form already does, it needs no change).

Internal neutralizing anonymous classes in Repeater::createTemplate()
and Blueprint::generateLatte() are simplified to plain `new Form`.

Author: dg

CLAUDE.md

@@ -63,11 +63,15 @@ npm run lint:fix
 ### Core PHP Structure
 
 **Class Hierarchy:**
-- `Form` (extends `Container`) - Main entry point for form creation
+- `Form` (extends `Container`) - Detached form: builds, validates and renders, but has no access to submitted data (`isAnchored()` returns `false`; submission API throws)
+- `StandaloneForm` (extends `Form`) - Detects submission and processes its own HTTP request (`$httpRequest`, static `initialize()`, `receiveHttpData()`, hidden `_form_` tracker); use outside Nette Application
+- `Nette\Application\UI\Form` (in nette/application, extends `Form`) - Anchored via presenter signals
 - `Container` - Holds controls and nested containers
 - `Control` (interface) - Contract for all form controls
 - `BaseControl` (abstract) - Base implementation for controls
 
+Subclasses providing their own source of submitted data must override `receiveHttpData()` together with `isAnchored()` (or extend `StandaloneForm`).
+
 **Form Controls** (in `src/Forms/Controls/`):
 - Abstract bases: `BaseControl`, `TextBase`, `ChoiceControl`, `MultiChoiceControl`
 - Text inputs: `TextInput` (also email/password/number via `addEmail()`, `addPassword()`, `addInteger()`, etc.), `TextArea`
@@ -169,6 +173,13 @@ testException('description', function () {
 - `addSubmit()` gained an `$onSubmit` parameter
 - Removed deprecated functionality and deprecated some magic properties (BC break)
 
+### Breaking Changes (v4.0)
+
+- Submitted data are accessed layer by layer via `getSubmittedData()` & `getSubmittedValue()`; `getHttpData()` is deprecated
+- Standalone HTTP processing split off `Form` into new `StandaloneForm`: `new Form` no longer autodetects submission (submission API throws `InvalidStateException`), `Form::initialize()` removed (use `StandaloneForm::initialize()`), `TrackerId`/`$httpRequest` moved to `StandaloneForm`, `Form::isAnchored()` returns `false`
+
+(Design rationale for both changes is recorded as ADRs 0001 and 0002 in the machine-local private `docs/decisions/`, which exists only in the primary working clone.)
+
 ### New Latte features (v3.3)
 
 - `{form scope name}` as an alternative to `{formContext name}`
@@ -527,8 +538,8 @@ $form->addPassword('passwordVerify')
 
 **Sec-Fetch/Origin header protection** (enabled by default):
 ```php
-// Create form before sending output to set _nss cookie
-$form = new Form;
+// standalone usage; POST submissions require the Sec-Fetch-Site: same-origin header
+$form = new StandaloneForm;
 ```
 
 **Cross-origin forms** (use carefully):

examples/basic-example.php

@@ -9,15 +9,15 @@
 	die('Install packages using `composer install`');
 }
 
-use Nette\Forms\Form;
+use Nette\Forms\StandaloneForm;
 use Nette\Utils\Html;
 use Tracy\Debugger;
 use Tracy\Dumper;
 
 Debugger::enable();
 
 
-$form = new Form;
+$form = new StandaloneForm;
 
 // group Personal data
 $form->addGroup('Personal data')

examples/bootstrap4-rendering.php

@@ -10,6 +10,7 @@
 }
 
 use Nette\Forms\Form;
+use Nette\Forms\StandaloneForm;
 use Tracy\Debugger;
 use Tracy\Dumper;
 
@@ -53,7 +54,7 @@ function makeBootstrap4(Form $form): void
 }
 
 
-$form = new Form;
+$form = new StandaloneForm;
 $form->onRender[] = 'makeBootstrap4';
 
 $form->addGroup('Personal data');

examples/bootstrap5-rendering.php

@@ -10,6 +10,7 @@
 }
 
 use Nette\Forms\Form;
+use Nette\Forms\StandaloneForm;
 use Tracy\Debugger;
 use Tracy\Dumper;
 
@@ -53,7 +54,7 @@ function makeBootstrap5(Form $form): void
 }
 
 
-$form = new Form;
+$form = new StandaloneForm;
 $form->onRender[] = 'makeBootstrap5';
 
 $form->addGroup('Personal data');

examples/containers.php

@@ -9,14 +9,14 @@
 	die('Install packages using `composer install`');
 }
 
-use Nette\Forms\Form;
+use Nette\Forms\StandaloneForm;
 use Tracy\Debugger;
 use Tracy\Dumper;
 
 Debugger::enable();
 
 
-$form = new Form;
+$form = new StandaloneForm;
 
 // group First person
 $form->addGroup('First person');

examples/custom-control.php

@@ -10,6 +10,7 @@
 }
 
 use Nette\Forms\Form;
+use Nette\Forms\StandaloneForm;
 use Nette\Forms\Helpers;
 use Nette\Utils\Html;
 
@@ -106,7 +107,7 @@ public static function validateDate(Nette\Forms\Control $control): bool
 
 Tracy\Debugger::enable();
 
-$form = new Form;
+$form = new StandaloneForm;
 
 $form['date'] = new DateInput('Date:');
 $form['date']->setDefaultValue(new DateTime);

examples/custom-rendering.php

@@ -9,15 +9,15 @@
 	die('Install packages using `composer install`');
 }
 
-use Nette\Forms\Form;
+use Nette\Forms\StandaloneForm;
 use Nette\Utils\Html;
 use Tracy\Debugger;
 use Tracy\Dumper;
 
 Debugger::enable();
 
 
-$form = new Form;
+$form = new StandaloneForm;
 // setup custom rendering
 $renderer = $form->getRenderer();
 $renderer->wrappers['form']['container'] = Html::el('div')->id('form');

examples/custom-validator.php

@@ -9,7 +9,7 @@
 	die('Install packages using `composer install`');
 }
 
-use Nette\Forms\Form;
+use Nette\Forms\StandaloneForm;
 use Tracy\Debugger;
 use Tracy\Dumper;
 
@@ -26,7 +26,7 @@ public static function divisibilityValidator($item, $arg): bool
 }
 
 
-$form = new Form;
+$form = new StandaloneForm;
 
 $form->addText('num1', 'Multiple of 8:')
 	->setDefaultValue(5)

examples/html5.php

@@ -9,14 +9,14 @@
 	die('Install packages using `composer install`');
 }
 
-use Nette\Forms\Form;
+use Nette\Forms\StandaloneForm;
 use Tracy\Debugger;
 use Tracy\Dumper;
 
 Debugger::enable();
 
 
-$form = new Form;
+$form = new StandaloneForm;
 
 $form->addGroup();
 

examples/latte.php

@@ -9,14 +9,14 @@
 	die('Install packages using `composer install`');
 }
 
-use Nette\Forms\Form;
+use Nette\Forms\StandaloneForm;
 use Tracy\Debugger;
 use Tracy\Dumper;
 
 Debugger::enable();
 
 
-$form = new Form;
+$form = new StandaloneForm;
 $form->addText('name', 'Your name')
 	->setRequired('Enter your name')
 	->setOption('description', 'Name and surname');