FormNode: deprecate missing comma before {form} arguments

The {form name attr=val} syntax (no comma between the name and the
attributes) was tolerated. Trigger E_USER_DEPRECATED when a token
follows the name without a comma, pointing to the offending column.
The form still compiles — this only nudges users toward the canonical
{form name, attr=val} so future syntax extensions can use bare
keywords next to the name unambiguously.

Author: dg

src/Bridges/FormsLatte/Nodes/FormNode.php

@@ -41,7 +41,10 @@ public static function create(Tag $tag): \Generator
 		$tag->expectArguments();
 		$node = $tag->node = new static;
 		$node->name = $tag->parser->parseUnquotedStringOrExpression();
-		$tag->parser->stream->tryConsume(',');
+		if (!$tag->parser->stream->tryConsume(',') && !$tag->parser->isEnd()) {
+			$position = $tag->parser->stream->peek()->position;
+			trigger_error("Missing comma before arguments in {{$tag->name}} tag $position.", E_USER_DEPRECATED);
+		}
 		$node->attributes = $tag->parser->parseArguments();
 		$node->print = $tag->name === 'form';
 

tests/Forms.Latte/forms.commaWarning.phpt

@@ -0,0 +1,44 @@
+<?php declare(strict_types=1);
+
+use Nette\Bridges\FormsLatte\FormsExtension;
+use Nette\Forms\Form;
+use Tester\Assert;
+
+require __DIR__ . '/../bootstrap.php';
+
+
+$form = new Form;
+$form->addText('name');
+
+$latte = new Latte\Engine;
+$latte->setLoader(new Latte\Loaders\StringLoader);
+$latte->addExtension(new FormsExtension);
+$latte->addProvider('uiControl', ['myForm' => $form]);
+
+
+test('no warning when only the form name is given', function () use ($latte) {
+	Assert::noError(fn() => $latte->compile("{form myForm}{/form}\n"));
+});
+
+
+test('no warning when comma separates name and arguments', function () use ($latte) {
+	Assert::noError(fn() => $latte->compile("{form myForm, class => 'a'}{/form}\n"));
+});
+
+
+test('deprecation warning when comma is missing before arguments', function () use ($latte) {
+	Assert::error(
+		fn() => $latte->compile("{form myForm class => 'a'}{/form}\n"),
+		E_USER_DEPRECATED,
+		'Missing comma before arguments in {form} tag on line 1 at column 14.',
+	);
+});
+
+
+test('deprecation warning also fires for {formContext}', function () use ($latte) {
+	Assert::error(
+		fn() => $latte->compile("{formContext myForm extra}{/formContext}\n"),
+		E_USER_DEPRECATED,
+		'Missing comma before arguments in {formContext} tag on line 1 at column 21.',
+	);
+});

tests/Forms.Latte/templates/forms.latte

@@ -1,4 +1,4 @@
-{form myForm id => myForm, class=>"ajax"}
+{form myForm, id => myForm, class=>"ajax"}
 	{foreach [id, username, select, area, send] as $name}
 		{label $name /}
 		{input $name title => Hello, size => 10}