Deprecate dropping columns referenced by constraints

Author: morozov

UPGRADE.md

@@ -6,6 +6,12 @@ awareness about deprecated code.
 - Use of our low-overhead runtime deprecation API, details:
   https://github.com/doctrine/deprecations/
 
+# Upgrade to 4.3
+
+## Deprecated dropping columns referenced by constraints
+
+Dropping columns that are referenced by constraints is deprecated. The constraints should be dropped first.
+
 # Upgrade to 4.2
 
 ## Support for new PDO subclasses on PHP 8.4

src/Schema/Table.php

@@ -14,10 +14,14 @@
 use Doctrine\DBAL\Schema\Exception\PrimaryKeyAlreadyExists;
 use Doctrine\DBAL\Schema\Exception\UniqueConstraintDoesNotExist;
 use Doctrine\DBAL\Types\Type;
+use Doctrine\Deprecations\Deprecation;
 use LogicException;
 
 use function array_merge;
 use function array_values;
+use function count;
+use function implode;
+use function in_array;
 use function preg_match;
 use function sprintf;
 use function strtolower;
@@ -332,6 +336,30 @@ public function dropColumn(string $name): self
     {
         $name = $this->normalizeIdentifier($name);
 
+        $foreignKeyConstraintNames = $this->getForeignKeyConstraintNamesByLocalColumnName($name);
+        $uniqueConstraintNames     = $this->getUniqueConstraintNamesByColumnName($name);
+
+        if (count($foreignKeyConstraintNames) > 0 || count($uniqueConstraintNames) > 0) {
+            $constraints = [];
+
+            if (count($foreignKeyConstraintNames) > 0) {
+                $constraints[] = 'foreign key constraints: ' . implode(', ', $foreignKeyConstraintNames);
+            }
+
+            if (count($uniqueConstraintNames) > 0) {
+                $constraints[] = 'unique constraints: ' . implode(', ', $uniqueConstraintNames);
+            }
+
+            Deprecation::trigger(
+                'doctrine/dbal',
+                'https://github.com/doctrine/dbal/pull/6558',
+                'Dropping columns referenced by constraints is deprecated.'
+                    . 'Column %s is used by the following constraints: %s ',
+                $name,
+                implode(', ', $constraints),
+            );
+        }
+
         unset($this->_columns[$name]);
 
         return $this;
@@ -800,4 +828,36 @@ private function _createIndex(
 
         return new Index($indexName, $columns, $isUnique, $isPrimary, $flags, $options);
     }
+
+    /** @return list<string> */
+    private function getForeignKeyConstraintNamesByLocalColumnName(string $columnName): array
+    {
+        $names = [];
+
+        foreach ($this->_fkConstraints as $name => $constraint) {
+            if (! in_array($columnName, $constraint->getLocalColumns(), true)) {
+                continue;
+            }
+
+            $names[] = $name;
+        }
+
+        return $names;
+    }
+
+    /** @return list<string> */
+    private function getUniqueConstraintNamesByColumnName(string $columnName): array
+    {
+        $names = [];
+
+        foreach ($this->uniqueConstraints as $name => $constraint) {
+            if (! in_array($columnName, $constraint->getColumns(), true)) {
+                continue;
+            }
+
+            $names[] = $name;
+        }
+
+        return $names;
+    }
 }

tests/Schema/TableTest.php

@@ -15,6 +15,7 @@
 use Doctrine\DBAL\Schema\UniqueConstraint;
 use Doctrine\DBAL\Types\Type;
 use Doctrine\DBAL\Types\Types;
+use Doctrine\Deprecations\PHPUnit\VerifyDeprecations;
 use LogicException;
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
@@ -24,6 +25,8 @@
 
 class TableTest extends TestCase
 {
+    use VerifyDeprecations;
+
     public function testCreateWithInvalidTableName(): void
     {
         $this->expectException(Exception::class);
@@ -905,4 +908,33 @@ public function testRemoveUniqueConstraintUnknownNameThrowsException(): void
 
         $table->removeUniqueConstraint('unique_constraint');
     }
+
+    public function testDropColumnWithForeignKeyConstraint(): void
+    {
+        $table = new Table('t1');
+        $table->addColumn('id', Types::INTEGER);
+        $table->addForeignKeyConstraint('t2', ['id'], ['id']);
+
+        $this->expectDeprecationWithIdentifier('https://github.com/doctrine/dbal/pull/6558');
+        $table->dropColumn('id');
+    }
+
+    public function testDropColumnWithUniqueConstraint(): void
+    {
+        $table = new Table('t');
+        $table->addColumn('id', Types::INTEGER);
+        $table->addUniqueConstraint(['id']);
+
+        $this->expectDeprecationWithIdentifier('https://github.com/doctrine/dbal/pull/6558');
+        $table->dropColumn('id');
+    }
+
+    public function testDropColumnWithoutConstraints(): void
+    {
+        $table = new Table('t');
+        $table->addColumn('id', Types::INTEGER);
+
+        $this->expectNoDeprecationWithIdentifier('https://github.com/doctrine/dbal/pull/6558');
+        $table->dropColumn('id');
+    }
 }