Remove code compensating for a schema comparison flaw

This code was relevant before the improvement in
#4746 was implemented. The new
comparator API is enforced in
#4771.

Now, the comparator will not produce a false-positive diff which is
enforced by the new test.

Author: morozov

src/Platforms/OraclePlatform.php

@@ -15,7 +15,6 @@
 use Doctrine\DBAL\Schema\Sequence;
 use Doctrine\DBAL\Schema\TableDiff;
 use Doctrine\DBAL\TransactionIsolationLevel;
-use Doctrine\DBAL\Types\BinaryType;
 use InvalidArgumentException;
 
 use function array_merge;
@@ -573,17 +572,6 @@ public function getAlterTableSQL(TableDiff $diff): array
 
             $column = $columnDiff->column;
 
-            // Do not generate column alteration clause if type is binary and only fixed property has changed.
-            // Oracle only supports binary type columns with variable length.
-            // Avoids unnecessary table alteration statements.
-            if (
-                $column->getType() instanceof BinaryType &&
-                $columnDiff->hasChanged('fixed') &&
-                count($columnDiff->changedProperties) === 1
-            ) {
-                continue;
-            }
-
             $columnHasChangedComment = $columnDiff->hasChanged('comment');
 
             /**

tests/Functional/Schema/Oracle/ComparatorTest.php

@@ -0,0 +1,63 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\DBAL\Tests\Functional\Schema\Oracle;
+
+use Doctrine\DBAL\Platforms\OraclePlatform;
+use Doctrine\DBAL\Schema\AbstractSchemaManager;
+use Doctrine\DBAL\Schema\Comparator;
+use Doctrine\DBAL\Schema\Table;
+use Doctrine\DBAL\Tests\Functional\Schema\ComparatorTestUtils;
+use Doctrine\DBAL\Tests\FunctionalTestCase;
+use Doctrine\DBAL\Types\Types;
+
+final class ComparatorTest extends FunctionalTestCase
+{
+    private AbstractSchemaManager $schemaManager;
+
+    private Comparator $comparator;
+
+    protected function setUp(): void
+    {
+        if (! $this->connection->getDatabasePlatform() instanceof OraclePlatform) {
+            self::markTestSkipped('This test covers Oracle-specific schema comparison scenarios.');
+        }
+
+        $this->schemaManager = $this->connection->createSchemaManager();
+        $this->comparator    = $this->schemaManager->createComparator();
+    }
+
+    /**
+     * Oracle does not support fixed length binary columns. The DBAL will map the {@see Types::BINARY} type
+     * to the variable-length RAW column type regardless of the "fixed" attribute.
+     *
+     * There should not be a diff when comparing a variable-length and a fixed-length column
+     * that are otherwise the same.
+     *
+     * @see OraclePlatform::getBinaryTypeDeclarationSQLSnippet()
+     */
+    public function testChangeBinaryColumnFixed(): void
+    {
+        $table  = new Table('comparator_test');
+        $column = $table->addColumn('id', Types::BINARY, [
+            'length' => 32,
+            'fixed' => true,
+        ]);
+        $this->dropAndCreateTable($table);
+
+        $column->setFixed(false);
+
+        self::assertNull(ComparatorTestUtils::diffFromActualToDesiredTable(
+            $this->schemaManager,
+            $this->comparator,
+            $table
+        ));
+
+        self::assertNull(ComparatorTestUtils::diffFromDesiredToActualTable(
+            $this->schemaManager,
+            $this->comparator,
+            $table
+        ));
+    }
+}