FIX Attempt to rebuild the schema if a schema file is missing

src/Schema/Storage/AbstractTypeRegistry.php

@@ -9,6 +9,10 @@
 use GraphQL\Type\Definition\ListOfType;
 use Exception;
 use SilverStripe\Core\Injector\Injector;
+use SilverStripe\GraphQL\Schema\SchemaBuilder;
+use SilverStripe\GraphQL\Schema\Exception\EmptySchemaException;
+use SilverStripe\Control\Controller;
+use SilverStripe\GraphQL\Controller as GraphQLController;
 
 abstract class AbstractTypeRegistry
 {
@@ -21,7 +25,30 @@ abstract class AbstractTypeRegistry
      */
     public static function get(string $typename)
     {
-        return static::fromCache($typename);
+        try {
+            return static::fromCache($typename);
+        } catch (Exception $e) {
+            if (!Controller::has_curr() ||
+                !(Controller::curr() instanceof GraphQLController) ||
+                !Controller::curr()->autobuildEnabled()
+            ) {
+                throw $e;
+            }
+            // Try to rebuild the whole schema as fallback.
+            // This is to solve mysterious edge cases where schema files do not exist when they should.
+            // These edge cases are more likely on multi-server environments
+            $dirParts = explode(DIRECTORY_SEPARATOR, static::getSourceDirectory());
+            $key = $dirParts[count($dirParts) - 1];
+            $builder = SchemaBuilder::singleton();
+            $schema = $builder->boot($key);
+            try {
+                $builder->build($schema, true);
+            } catch (EmptySchemaException $e) {
+                // noop
+            }
+            // Attempt to return again now the schema has been rebuilt.
+            return static::fromCache($typename);
+        }
     }
 
     abstract protected static function getSourceDirectory(): string;

tests/Schema/IntegrationTest.php

@@ -1215,6 +1215,12 @@ private function createSchema(TestSchemaBuilder $factory): Schema
 
         $factory->build($schema, true);
 
+        // Register as the default SchemaBuilder so that any calls to
+        // SchemaBuidler::singleton() get this TestSchemaBuilder
+        // This is important for the call in AbstractTypeRegisty::get() because
+        // otherwise a duplicate .graphql-generated folder will be created
+        Injector::inst()->registerService($factory, SchemaBuilder::class);
+
         return $schema;
     }