Squash core migrations (#2842)

Data migrations (seed default groups, seed default permissions) are deliberately excluded.
This also allows us to remove a lot of now unnecessary public API from the migrator and migration repository.

src/Database/Console/GenerateDumpCommand.php

@@ -0,0 +1,87 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Database\Console;
+
+use Flarum\Console\AbstractCommand;
+use Flarum\Foundation\Paths;
+use Illuminate\Database\Connection;
+
+class GenerateDumpCommand extends AbstractCommand
+{
+    /**
+     * @var Connection
+     */
+    protected $connection;
+
+    /**
+     * @var Paths
+     */
+    protected $paths;
+
+    /**
+     * @param Connection $connection
+     * @param Paths $paths
+     */
+    public function __construct(Connection $connection, Paths $paths)
+    {
+        $this->connection = $connection;
+        $this->paths = $paths;
+
+        parent::__construct();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function configure()
+    {
+        $this
+            ->setName('schema:dump')
+            ->setDescription('Dump DB schema');
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function fire()
+    {
+        $dumpPath = __DIR__.'/../../../migrations/install.dump';
+        /** @var Connection */
+        $connection = resolve('db.connection');
+
+        $connection
+            ->getSchemaState()
+            ->withMigrationTable($connection->getTablePrefix().'migrations')
+            ->handleOutputUsing(function ($type, $buffer) {
+                $this->output->write($buffer);
+            })
+            ->dump($connection, $dumpPath);
+
+        // We need to remove any data migrations, as those won't be captured
+        // in the schema dump, and must be run separately.
+        $coreDataMigrations = [
+            '2018_07_21_000000_seed_default_groups',
+            '2018_07_21_000100_seed_default_group_permissions',
+        ];
+
+        $newDump = [];
+        $dump = file($dumpPath);
+        foreach ($dump as $line) {
+            foreach ($coreDataMigrations as $excludeMigrationId) {
+                if (strpos($line, $excludeMigrationId) !== false) {
+                    continue 2;
+                }
+            }
+            $newDump[] = $line;
+        }
+
+        file_put_contents($dumpPath, implode($newDump));
+    }
+}