New rule: No footnotes (#1494)

docs/rules.md

@@ -56,6 +56,7 @@
 * [no_directive_after_shorthand](#no_directive_after_shorthand)
 * [no_duplicate_use_statements](#no_duplicate_use_statements)
 * [no_explicit_use_of_code_block_php](#no_explicit_use_of_code_block_php)
+* [no_footnotes](#no_footnotes)
 * [no_inheritdoc_in_code_examples](#no_inheritdoc_in_code_examples)
 * [no_merge_conflict](#no_merge_conflict)
 * [no_namespace_after_use_statements](#no_namespace_after_use_statements)
@@ -654,6 +655,18 @@ It's an example
 
 #### Groups [`@Symfony`]
 
+## `no_footnotes`
+
+  > _Make sure there is no footnotes_
+
+#### Groups [`@Symfony`]
+
+##### Invalid Examples :-1:
+
+```rst
+.. [5] A numerical footnote. Note
+```
+
 ## `no_inheritdoc_in_code_examples`
 
 #### Groups [`@Sonata`, `@Symfony`]

src/Rule/NoFootnotes.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * This file is part of DOCtor-RST.
+ *
+ * (c) Oskar Stark <oskarstark@googlemail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Rule;
+
+use App\Attribute\Rule\Description;
+use App\Attribute\Rule\InvalidExample;
+use App\Rst\RstParser;
+use App\Value\Lines;
+use App\Value\NullViolation;
+use App\Value\RuleGroup;
+use App\Value\Violation;
+use App\Value\ViolationInterface;
+#[Description('Make sure there is no footnotes')]
+#[InvalidExample('.. [5] A numerical footnote. Note')]
+class NoFootnotes extends AbstractRule implements LineContentRule
+{
+    public static function getGroups(): array
+    {
+        return [
+            RuleGroup::Symfony(),
+        ];
+    }
+
+    public function check(Lines $lines, int $number, string $filename): ViolationInterface
+    {
+        $lines->seek($number);
+        $line = $lines->current();
+
+        if (RstParser::isFootnote($lines->current())) {
+            return Violation::from(
+                "Please don't use footnotes as they are not supported",
+                $filename,
+                $number + 1,
+                $line,
+            );
+        }
+
+        return NullViolation::create();
+    }
+}

tests/Rule/NoFootnotesTest.php

@@ -0,0 +1,55 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * This file is part of DOCtor-RST.
+ *
+ * (c) Oskar Stark <oskarstark@googlemail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Tests\Rule;
+
+use App\Rule\NoFootnotes;
+use App\Tests\RstSample;
+use App\Value\NullViolation;
+use App\Value\Violation;
+use App\Value\ViolationInterface;
+
+final class NoFootnotesTest extends \App\Tests\UnitTestCase
+{
+    /**
+     * @test
+     *
+     * @dataProvider checkProvider
+     */
+    public function check(ViolationInterface $expected, RstSample $sample): void
+    {
+        self::assertEquals(
+            $expected,
+            (new NoFootnotes())->check($sample->lines(), $sample->lineNumber(), 'filename'),
+        );
+    }
+
+    public static function checkProvider(): array
+    {
+        return [
+            [
+                Violation::from(
+                    "Please don't use footnotes as they are not supported",
+                    'filename',
+                    1,
+                    '.. [5] A numerical footnote. Note',
+                ),
+                new RstSample('.. [5] A numerical footnote. Note'),
+            ],
+            [
+                NullViolation::create(),
+                new RstSample('.. _`Symfony`: https://symfony.com'),
+            ],
+        ];
+    }
+}