fix: reject damaged migration sources

bin/migrate

@@ -67,7 +67,10 @@ $ids      = $srcstore->getAllPastes();
 
 foreach ($ids as $id) {
     debug("Reading document ID " . $id);
-    $paste    = $srcstore->read($id);
+    $paste = $srcstore->read($id);
+    if (!is_array($paste)) {
+        dieerr("Unable to read document ID " . $id);
+    }
     $comments = $srcstore->readComments($id);
 
     savePaste($force_overwrite, $dryrun, $id, $paste, $dststore);

tst/MigrateTest.php

@@ -81,4 +81,35 @@ class MigrateTest extends TestCase
         $this->assertTrue($this->_model_1->exists(Helper::getPasteId()), 'paste migrated back');
         $this->assertTrue($this->_model_1->existsComment(Helper::getPasteId(), Helper::getPasteId(), Helper::getCommentId()), 'comment migrated back');
     }
+
+    public function testDamagedSourcePasteIsPreserved()
+    {
+        $this->_model_1->delete(Helper::getPasteId());
+        $paste = Helper::getPaste();
+        $this->_model_1->create(Helper::getPasteId(), $paste);
+        file_put_contents(
+            $this->_path_instance_1 . DIRECTORY_SEPARATOR . 'data' . DIRECTORY_SEPARATOR .
+            substr(Helper::getPasteId(), 0, 2) . DIRECTORY_SEPARATOR .
+            substr(Helper::getPasteId(), 2, 2) . DIRECTORY_SEPARATOR .
+            Helper::getPasteId() . '.php',
+            Filesystem::PROTECTION_LINE . PHP_EOL . '{'
+        );
+
+        $output    = null;
+        $exit_code = 0;
+        exec(
+            'php ' . PATH . 'bin' . DIRECTORY_SEPARATOR . 'migrate --delete-after ' .
+            $this->_path_instance_1 . DIRECTORY_SEPARATOR . 'cfg ' .
+            $this->_path_instance_2 . DIRECTORY_SEPARATOR . 'cfg 2>&1',
+            $output,
+            $exit_code
+        );
+
+        $this->assertSame(1, $exit_code, implode(PHP_EOL, $output));
+        $this->assertStringContainsString(
+            'ERROR: Unable to read document ID ' . Helper::getPasteId(),
+            implode(PHP_EOL, $output)
+        );
+        $this->assertTrue($this->_model_1->exists(Helper::getPasteId()));
+    }
 }