Synapse Server Crash: TypeError Fix Guide

Dec 2, 2025 by Admin 42 views

Hey guys! Running into a frustrating TypeError when trying to fire up your Synapse server? Specifically, seeing the error unsupported operand type(s) for |: 'InterfaceClass' and 'NoneType'? Don't worry, this guide is here to help you troubleshoot and get your server back online. We'll break down what this error means, what might be causing it, and how to fix it, so let's dive right in!

Understanding the TypeError

This TypeError is a common issue that can arise when using Python, especially with type hinting and union types. In simpler terms, it means you're trying to perform an operation (in this case, the | operator, often used to define union types) between two incompatible types: an InterfaceClass and NoneType. Let's try to explain this a bit more, so you get what is happening under the hood.

Breaking Down the Error Message

TypeError: This indicates that you are attempting an operation on incompatible data types.
unsupported operand type(s) for |: This specifies that the | operator (used for creating a union of types) is the culprit.
'InterfaceClass' and 'NoneType': This clearly shows the conflicting types involved. You're trying to combine an interface class with None, which isn't a valid operation in this context.

What Causes This Error in Synapse?

In the context of Synapse, this error often surfaces after an update or when there are inconsistencies in the installed packages or their dependencies. It usually happens because of changes in the code where a variable is expected to be of a certain type (an InterfaceClass), but it can sometimes be None. This can occur due to various reasons, such as:

Incompatible Package Versions: Synapse depends on numerous packages, and if some of these are not compatible with each other, it can lead to such type errors.
Upgrade Issues: Sometimes, during an upgrade, not all dependencies are correctly updated, leaving the system in an inconsistent state.
Code Changes: A recent update to Synapse (as the original issue reporter suspected with #19111) might have introduced a change that exposed this type incompatibility.

Troubleshooting Steps

Okay, now that we understand the error, let's get our hands dirty and try to fix it. Here’s a systematic approach to troubleshooting this TypeError: unsupported operand type(s) for |: 'InterfaceClass' and 'NoneType'.

1. Check Your Python Version

Synapse has specific Python version requirements. The original reporter was using Python 3.11, which should be compatible, but it's always good to double-check.

Verify: Ensure your Python version meets the minimum requirements for your Synapse version. Refer to the Synapse documentation for compatibility information. Run python3 --version to check.
Action: If your Python version is outdated, consider upgrading to a compatible version. However, be cautious when upgrading Python, as it can affect other applications on your system. Always test in a development environment first.

2. Verify Synapse Version

Confirm the exact version of Synapse you are running. The reporter mentioned using version 1.143.0. Knowing this will help in identifying version-specific issues.

Verify: Check the Synapse version using pip show matrix-synapse.
Action: If you've recently upgraded, consider downgrading to the previous version to see if the issue persists. This can help determine if the upgrade caused the problem.

3. Update Synapse and its Dependencies

Outdated packages are a common cause of such errors. Ensure that Synapse and all its dependencies are up to date.

Update: Run pip install --upgrade matrix-synapse[postgres] to update Synapse and its PostgreSQL dependencies. Make sure to include any extra dependencies you use (like [ldap], etc).
Tip: Consider using a virtual environment to manage your Synapse installation. This isolates it from other Python projects and can prevent dependency conflicts. Use python3 -m venv .venv to create a virtual environment and then activate it with source .venv/bin/activate.

4. Clean Install

Sometimes, upgrading isn't enough, and a clean install is necessary to resolve dependency issues.

Uninstall: First, uninstall Synapse using pip uninstall matrix-synapse.
Clean: Manually remove any remaining Synapse-related files from your Python environment.
Reinstall: Reinstall Synapse using pip install matrix-synapse[postgres]. Again, remember any extra dependencies.

5. Check for Conflicting Packages

Conflicting packages can cause unexpected errors. Check for any packages that might be interfering with Synapse.

List: Use pip list to see all installed packages.
Identify: Look for any packages that might conflict with Synapse or its dependencies. Pay special attention to versions.
Resolve: If you find any conflicting packages, try uninstalling or downgrading them.

6. Review the Synapse Configuration

Although the reporter didn't provide configuration details, it's essential to ensure that your Synapse configuration is correct.

Check: Review your homeserver.yaml file for any misconfigurations.
Validate: Use the synapse.config tool to validate your configuration file.

7. Examine the Logs

The log output provides valuable clues about what's going wrong. The original report included a snippet, but more context might be needed.

Location: Check the Synapse log file (usually located in /var/log/synapse/) for detailed error messages.
Analyze: Look for any error messages or warnings that might indicate the cause of the problem.
Context: Pay attention to the lines leading up to the TypeError to understand the sequence of events.

8. Database Considerations

Since the reporter is using PostgreSQL, there might be database-related issues.

Check: Ensure that your PostgreSQL server is running and accessible.
Validate: Verify that the Synapse database user has the necessary permissions.
Inspect: Look for any database-related error messages in the Synapse logs.

9. Check Operating System and Platform Compatibility

The reporter is using Opensuse Leap 15.6. Ensure that your operating system is fully compatible with the version of Synapse you're running.

Verify: Check the Synapse documentation for any known issues with your operating system.
Update: Make sure your operating system is up to date with the latest patches and updates.

10. Python Virtual Environment

It seems they are not using a virtual environment, it is very important that you use it, to avoid global package conflicts.

Create: create a virtual environment with python3 -m venv .venv
Activate: activate the virtual environment with source .venv/bin/activate
Install: install the dependencies inside the virtual environment with pip install matrix-synapse[postgres]

Example Scenario and Solution

Let's imagine a scenario where this error occurs after upgrading Synapse from version 1.142.0 to 1.143.0. After the upgrade, the server fails to start with the dreaded TypeError. Here’s how you might approach the problem:

Downgrade: Downgrade back to version 1.142.0 using pip install matrix-synapse==1.142.0.
Test: Start the server to confirm that the downgrade resolves the issue.
Investigate: If the downgrade works, investigate the release notes for version 1.143.0 to see if there are any known issues or breaking changes related to the TypeError. Review the changes in https://github.com/matrix-org/synapse/releases
Report: If you can't find a solution, report the issue to the Synapse development team, providing detailed information about your environment, steps to reproduce the error, and any relevant log output.

Final Thoughts

The TypeError: unsupported operand type(s) for |: 'InterfaceClass' and 'NoneType' can be a bit tricky, but by systematically checking your environment, dependencies, and configuration, you should be able to identify and resolve the issue. Remember to consult the Synapse documentation and community resources for additional help. Good luck, and happy Synapsing!