[Backport 26.7] Fixed migration failure when dropping a legacy index that backs a foreign key on MySQL

lib/Maho/Db/Schema/Canonicalizer.php

@@ -11,6 +11,7 @@
 
 use Doctrine\DBAL\Schema\DefaultExpression\CurrentTimestamp;
 use Doctrine\DBAL\Schema\Index;
+use Doctrine\DBAL\Schema\Index\IndexType;
 use Doctrine\DBAL\Schema\Table;
 use Doctrine\DBAL\Types\FloatType;
 use Doctrine\DBAL\Types\SmallFloatType;
@@ -38,7 +39,9 @@
  *   - index names: introspected names vs DBAL's autogenerated ones;
  *   - phantom FK indexes: introspection synthesizes a single-column index for a
  *     foreign key backed only by a composite prefix, with no physical
- *     counterpart (see stripPhantomIndexes()).
+ *     counterpart (see stripPhantomIndexes());
+ *   - index column names: introspection marks them quoted, the declarative
+ *     schema leaves them bare (see unquoteIndexColumns()).
  *
  * The equivalence applied here is purely representational, so it never hides a
  * genuine structural difference. Methods mutate the passed tables in place;
@@ -56,6 +59,7 @@ final class Canonicalizer
     public static function reconcile(Table $live, Table $target, array $physicalLiveIndexNames): void
     {
         self::stripPhantomIndexes($live, $physicalLiveIndexNames);
+        self::unquoteIndexColumns($live);
         self::alignIndexNames($live, $target);
         self::alignTableCharset($live, $target);
         self::stripColumnComments($live);
@@ -103,6 +107,68 @@ private static function stripPhantomIndexes(Table $table, array $physicalIndexNa
         }
     }
 
+    /**
+     * Re-express every live index with bare column names.
+     *
+     * DBAL 4.4 introspection marks an index's column names as quoted, so the
+     * same index reads as ["customer_id"] live and [customer_id] in the target.
+     * The Comparator sees through that, but AbstractMySQLPlatform does not: it
+     * folds an index drop and an index creation over the same columns into one
+     * `ALTER TABLE ... DROP INDEX a, ADD INDEX b (...)` only when the two raw
+     * column lists match, read through Index::getColumns(), the same legacy
+     * accessor that leaked introspection quoting in doctrine/dbal#7392. Unfolded,
+     * the drop runs on its own, and MySQL refuses to drop the index backing a
+     * foreign key: "needed in a foreign key constraint" (error 1553, which
+     * FOREIGN_KEY_CHECKS=0 does not lift). That is every legacy install whose
+     * composite UNIQUE key the declarative target re-declares as a plain index.
+     *
+     * Each index keeps its own name, spelled exactly as introspected: that
+     * quoting is load-bearing on Postgres, where a legacy index named as a bare
+     * hex hash may start with a digit and is only valid quoted.
+     *
+     * @todo Drop this method (and its call in reconcile()) once
+     *       https://github.com/doctrine/dbal/pull/7475 (the upstream fix, which
+     *       compares the same column lists through Index::getIndexedColumns())
+     *       is released and composer.json requires a version carrying it. The
+     *       fold then matches on unquoted values on its own, and the quoting
+     *       becomes representation the Comparator already sees through.
+     */
+    private static function unquoteIndexColumns(Table $table): void
+    {
+        foreach ($table->getIndexes() as $index) {
+            if (self::isPrimaryIndex($table, $index)) {
+                continue;
+            }
+
+            $columns = [];
+            $lengths = [];
+            $quoted = false;
+            foreach ($index->getIndexedColumns() as $indexedColumn) {
+                $identifier = $indexedColumn->getColumnName()->getIdentifier();
+                $columns[] = $identifier->getValue();
+                $lengths[] = $indexedColumn->getLength();
+                $quoted = $quoted || $identifier->isQuoted();
+            }
+            if (!$quoted) {
+                continue;
+            }
+
+            $name = $index->getObjectName()->toString();
+            $type = $index->getType();
+            $table->dropIndex($name);
+            if ($type === IndexType::UNIQUE) {
+                $table->addUniqueIndex($columns, $name, ['lengths' => $lengths]);
+            } else {
+                $flags = match ($type) {
+                    IndexType::FULLTEXT => ['fulltext'],
+                    IndexType::SPATIAL => ['spatial'],
+                    default => [],
+                };
+                $table->addIndex($columns, $name, $flags, ['lengths' => $lengths]);
+            }
+        }
+    }
+
     /**
      * Rename each live index that matches a target index by structure to the
      * target's name, so the Comparator treats the pair as identical and emits

tests/Backend/Unit/Maho/Db/Schema/CanonicalizerTest.php

@@ -113,6 +113,35 @@ function canonTable(string $name): Table
     expect($live->hasIndex('LEGACY_HASH_NAME'))->toBeFalse();
 });
 
+it('re-expresses quoted live index columns as bare names', function () {
+    // What introspection produces: index name and column names marked quoted.
+    $live = canonTable('t');
+    $live->addColumn('customer_id', Types::INTEGER, ['unsigned' => true]);
+    $live->addColumn('product_id', Types::INTEGER, ['unsigned' => true]);
+    $live->addUniqueIndex(['"customer_id"', '"product_id"'], '"UNQ_LEGACY"');
+
+    $target = canonTable('t');
+    $target->addColumn('customer_id', Types::INTEGER, ['unsigned' => true]);
+    $target->addColumn('product_id', Types::INTEGER, ['unsigned' => true]);
+    $target->addIndex(['customer_id', 'product_id'], 'IDX_TARGET');
+
+    Canonicalizer::reconcile($live, $target, ['"UNQ_LEGACY"']);
+
+    // The bare column names let AbstractMySQLPlatform match this drop against
+    // the target's creation and fold both into a single ALTER TABLE.
+    $index = $live->getIndex('UNQ_LEGACY');
+    $columns = array_map(
+        static fn($indexedColumn): string => $indexedColumn->getColumnName()->getIdentifier()->getValue(),
+        $index->getIndexedColumns(),
+    );
+    expect($columns)->toBe(['customer_id', 'product_id']);
+    foreach ($index->getIndexedColumns() as $indexedColumn) {
+        expect($indexedColumn->getColumnName()->getIdentifier()->isQuoted())->toBeFalse();
+    }
+    // Uniqueness survives the rewrite: it is what makes this a real change.
+    expect($index->getType())->toBe(Doctrine\DBAL\Schema\Index\IndexType::UNIQUE);
+});
+
 it('drops a phantom index that has no physical counterpart', function () {
     $live = canonTable('t');
     $live->addColumn('a', Types::INTEGER, ['unsigned' => true]);