DiffGenerator: fixes circular references for removed tables

Author: janpecha

src/DiffGenerator.php

@@ -91,6 +91,7 @@ private function prepareChanges()
 			$this->updatedTables = $this->prepareUpdatedTables();
 			$this->removedTables = $this->prepareRemovedTables();
 			$this->fixCreatedCircularReferences();
+			$this->fixRemovedCircularReferences();
 			$this->prepared = TRUE;
 		}
 
@@ -501,6 +502,59 @@ private function fixCreatedCircularReferences()
 		}
 
 
+		/**
+		 * @return void
+		 */
+		private function fixRemovedCircularReferences()
+		{
+			$sortedTables = $this->sortTables($this->old->getTables(), $this->removedTables);
+			$exists = [];
+
+			foreach ($sortedTables as $sortedTable) {
+				$exists[$sortedTable->getTableName()] = TRUE;
+			}
+
+			$removedNames = [];
+
+			foreach ($sortedTables as $removedTable) {
+				$tableName = $removedTable->getTableName();
+
+				if (!isset($exists[$tableName])) {
+					$removedNames[$tableName] = [];
+					continue;
+				}
+
+				$definition = $this->old->getTable($removedTable->getTableName());
+
+				if ($definition === NULL) {
+					continue;
+				}
+
+				$updates = [];
+
+				foreach ($definition->getForeignKeys() as $foreignKey) {
+					$targetTable = $foreignKey->getTargetTable();
+
+					if (!isset($exists[$targetTable])) {
+						continue;
+					}
+
+					if (!isset($removedNames[$targetTable])) { // circular reference
+						$updates[] = new Diffs\RemovedForeignKey($tableName, $foreignKey->getName());
+					}
+				}
+
+				$removedNames[$tableName] = $updates;
+			}
+
+			foreach ($removedNames as $tableName => $updates) {
+				if (count($updates) > 0) {
+					$this->updatedTables[] = new Diffs\UpdatedTable($tableName, $updates);
+				}
+			}
+		}
+
+
 		private function sortTables(array $allTables, array $tablesToSort)
 		{
 			$tableOrder = $this->resolveOrder($allTables);

tests/SchemaGenerator/diffs/removed-table.phpt

@@ -17,3 +17,52 @@ test(function () {
 	$generator->generator->generate();
 	Assert::same("DROP TABLE `book`;\n", $generator->dumper->getSql());
 });
+
+
+test(function () { // circular dependency
+	$old = new SqlSchema\Schema;
+	$new = new SqlSchema\Schema;
+
+	$oldGallery = $old->addTable('gallery');
+	$oldGallery->addColumn('id', 'INT');
+	$oldGallery->addColumn('primaryPhoto_id', 'INT');
+	$oldGallery->addForeignKey('fk_primaryPhoto', 'primaryPhoto_id', 'photo', 'id');
+
+	$oldPhoto = $old->addTable('photo');
+	$oldPhoto->addColumn('id', 'INT');
+	$oldPhoto->addColumn('gallery_id', 'INT');
+	$oldPhoto->addForeignKey('fk_gallery', 'gallery_id', 'gallery', 'id');
+
+	$newGallery = $new->addTable('gallery');
+	$newGallery->addColumn('id', 'INT');
+
+	$generator = Test\TestGenerator::create($old, $new);
+	$generator->generator->generate();
+	Assert::same(implode("\n", [
+		'ALTER TABLE `gallery`',
+		'DROP FOREIGN KEY `fk_primaryPhoto`,',
+		'DROP COLUMN `primaryPhoto_id`;',
+		'',
+		"DROP TABLE `photo`;",
+	]) . "\n", $generator->dumper->getSql());
+});
+
+
+test(function () { // circular dependency - self reference
+	$old = new SqlSchema\Schema;
+	$new = new SqlSchema\Schema;
+
+	$oldGallery = $old->addTable('gallery');
+	$oldGallery->addColumn('id', 'INT');
+	$oldGallery->addColumn('parent_id', 'INT');
+	$oldGallery->addForeignKey('fk_parent', 'parent_id', 'gallery', 'id');
+
+	$generator = Test\TestGenerator::create($old, $new);
+	$generator->generator->generate();
+	Assert::same(implode("\n", [
+		'ALTER TABLE `gallery`',
+		'DROP FOREIGN KEY `fk_parent`;',
+		'',
+		"DROP TABLE `gallery`;",
+	]) . "\n", $generator->dumper->getSql());
+});