fix: main thread fix (#130)

* fix: main thread fix

* fix: adding test

Author: sattvikc

src/main/java/io/supertokens/storage/postgresql/ConnectionPool.java

@@ -133,9 +133,6 @@ static void initPool(Start start, boolean shouldWait) throws DbInitException {
         if (isAlreadyInitialised(start)) {
             return;
         }
-        if (Thread.currentThread() != start.mainThread) {
-            throw new DbInitException("Should not come here");
-        }
         Logging.info(start, "Setting up PostgreSQL connection pool.", true);
         boolean longMessagePrinted = false;
         long maxTryTime = System.currentTimeMillis() + getTimeToWaitToInit(start);

src/main/java/io/supertokens/storage/postgresql/Start.java

@@ -120,7 +120,7 @@ public class Start
     private static final String REFRESH_TOKEN_KEY_NAME = "refresh_token_key";
     public static boolean isTesting = false;
     boolean enabled = true;
-    Thread mainThread = Thread.currentThread();
+    static Thread mainThread = Thread.currentThread();
     private Thread shutdownHook;
 
     private boolean isBaseTenant = false;
@@ -2810,4 +2810,9 @@ public String[] getAllTablesInTheDatabaseThatHasDataForAppId(String appId) throw
             throw new StorageQueryException(e);
         }
     }
+
+    @TestOnly
+    public Thread getMainThread() {
+        return mainThread;
+    }
 }

src/test/java/io/supertokens/storage/postgresql/test/TestMainThread.java

@@ -0,0 +1,89 @@
+/*
+ *    Copyright (c) 2023, VRAI Labs and/or its affiliates. All rights reserved.
+ *
+ *    This software is licensed under the Apache License, Version 2.0 (the
+ *    "License") as published by the Apache Software Foundation.
+ *
+ *    You may not use this file except in compliance with the License. You may
+ *    obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ *    License for the specific language governing permissions and limitations
+ *    under the License.
+ */
+
+package io.supertokens.storage.postgresql.test;
+
+import com.google.gson.JsonObject;
+import io.supertokens.ProcessState;
+import io.supertokens.featureflag.EE_FEATURES;
+import io.supertokens.featureflag.FeatureFlagTestContent;
+import io.supertokens.pluginInterface.STORAGE_TYPE;
+import io.supertokens.pluginInterface.Storage;
+import io.supertokens.pluginInterface.multitenancy.TenantIdentifier;
+import io.supertokens.storage.postgresql.Start;
+import io.supertokens.storage.postgresql.test.httpRequest.HttpRequestForTesting;
+import io.supertokens.storageLayer.StorageLayer;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TestRule;
+
+import static org.junit.Assert.*;
+
+public class TestMainThread {
+    @Rule
+    public TestRule watchman = Utils.getOnFailure();
+
+    @AfterClass
+    public static void afterTesting() {
+        Utils.afterTesting();
+    }
+
+    @Before
+    public void beforeEach() {
+        Utils.reset();
+    }
+
+    @Test
+    public void testThatMainThreadIsSameThroughout() throws Exception {
+        String[] args = {"../"};
+
+        TestingProcessManager.TestingProcess process = TestingProcessManager.start(args);
+        FeatureFlagTestContent.getInstance(process.getProcess())
+                .setKeyValue(FeatureFlagTestContent.ENABLED_FEATURES, new EE_FEATURES[]{EE_FEATURES.MULTI_TENANCY});
+        process.startProcess();
+        assertNotNull(process.checkOrWaitForEvent(ProcessState.PROCESS_STATE.STARTED));
+
+        if (StorageLayer.getStorage(process.getProcess()).getType() != STORAGE_TYPE.SQL) {
+            return;
+        }
+
+        if (StorageLayer.isInMemDb(process.getProcess())) {
+            return;
+        }
+
+        Storage storage = StorageLayer.getBaseStorage(process.getProcess());
+        Thread mainThread = ((Start) storage).getMainThread();
+
+        // Create a new app
+        JsonObject config = new JsonObject();
+        storage.modifyConfigToAddANewUserPoolForTesting(config, 1);
+        JsonObject requestBody = new JsonObject();
+        requestBody.addProperty("appId", "a1");
+        requestBody.add("coreConfig", config);
+        HttpRequestForTesting.sendJsonPUTRequest(process.getProcess(), "", "http://localhost:3567/recipe/multitenancy/app",
+                requestBody, 1000, 2500, null,  "3.0", "multitenancy");
+
+        Storage storage2 = StorageLayer.getStorage(new TenantIdentifier(null, "a1", null), process.getProcess());
+
+        assertNotEquals(storage, storage2);
+        assertEquals(mainThread, ((Start) storage2).getMainThread());
+
+        process.kill();
+        assertNotNull(process.checkOrWaitForEvent(ProcessState.PROCESS_STATE.STOPPED));
+    }
+}