Verify DAP Server Configuration

Oct 13, 2025 by talynt.org 31 views

Introduction

The TestDAP_breakpointEvents.py test case in the lldb-dap project has been experiencing flakiness issues on macOS. This article aims to investigate the root cause of this flakiness and provide potential solutions to resolve the issue.

Background

The TestDAP_breakpointEvents.py test case is designed to test the breakpoint events functionality in the lldb-dap project. The test sets a breakpoint in a shared library and runs and stops the program to verify that the breakpoint events are correctly received by the DAP server.

Flakiness Issues

The flakiness issues with TestDAP_breakpointEvents.py have been observed on multiple occasions, with the test failing to run successfully. The failure reports from the Green Lab test results indicate that the test fails with an assertion error, stating that the number of breakpoint events received by the DAP server is not equal to 1.

Example Failure Report

The following is an example failure report from the Green Lab test results:

FAIL: test_breakpoint_events (TestDAP_breakpointEvents.TestDAP_breakpointEvents)
   This test sets a breakpoint in a shared library and runs and stops
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/tools/lldb-dap/breakpoint-events/TestDAP_breakpointEvents.py", line 90, in test_breakpoint_events
    self.assertEqual(len(self.dap_server.breakpoint_events), 1)
AssertionError: 0 != 1
Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
----------------------------------------------------------------------

Investigation

To investigate the root cause of the flakiness issue, we need to analyze the test case and the DAP server's behavior. Here are some potential causes of the issue:

DAP Server Configuration: The DAP server's configuration might be causing the issue. For example, the server might not be configured to receive breakpoint events, or the configuration might be incorrect.
Test Case Implementation: The test case implementation might be causing the issue. For example, the test case might be setting the breakpoint incorrectly, or the test case might be expecting the wrong number of breakpoint events.
LLDB Build Configuration: The LLDB build configuration might be causing the issue. For example, the build configuration might be incorrect, or the build might be missing some necessary dependencies.

Potential Solutions

Based on the investigation, here are some potential solutions to resolve the flakiness issue:

Verify DAP Server Configuration: Verify that the DAP server is correctly configured to receive breakpoint events. Check the server's configuration and ensure that it is set up correctly.
Review Test Case Implementation: Review the test case implementation to ensure that it is setting the breakpoint correctly and expecting the correct number of breakpoint events.
Check LLDB Build Configuration: Check the LLDB build configuration to ensure that it is correct and that all necessary dependencies are included.

Conclusion

The TestDAP_breakpointEvents.py test case in the lldb-dap project has been experiencing flakiness issues on macOS. The investigation suggests that the issue might be caused by the DAP server's configuration, the test case implementation, or the LLDB build configuration. Potential solutions include verifying the DAP server configuration, reviewing the test case implementation, and checking the LLDB build configuration.

Recommendations

To resolve the flakiness issue, we recommend the following:

Verify DAP Server Configuration: Verify that the DAP server is correctly configured to receive breakpoint events.
Review Test Case Implementation: Review the test case implementation to ensure that it is setting the breakpoint correctly and expecting the correct number of breakpoint events.
Check LLDB Build Configuration: Check the LLDB build configuration to ensure that it is correct and that all necessary dependencies are included.

Future Work

To further investigate the flakiness issue, we recommend the following:

Add Logging: Add logging to the test case to capture more information about the test case's behavior.
Use Debugging Tools: Use debugging tools to capture more information about the DAP server's behavior.
Collaborate with Other Teams: Collaborate with other teams to gather more information about the issue and potential solutions.

References

TestDAP_breakpointEvents.py
Green Lab Test Results
lldb-dap] TestDAP_breakpointEvents.py is flaky: Q&A =====================================================

Q: What is the `TestDAP_breakpointEvents.py` test case?

A: The TestDAP_breakpointEvents.py test case is a test case in the lldb-dap project that is designed to test the breakpoint events functionality in the DAP server.

Q: What is the purpose of the `TestDAP_breakpointEvents.py` test case?

A: The purpose of the TestDAP_breakpointEvents.py test case is to verify that the breakpoint events are correctly received by the DAP server when a breakpoint is set in a shared library and the program is run and stopped.

Q: What is the flakiness issue with the `TestDAP_breakpointEvents.py` test case?

A: The flakiness issue with the TestDAP_breakpointEvents.py test case is that it fails to run successfully on multiple occasions, with the test failing with an assertion error stating that the number of breakpoint events received by the DAP server is not equal to 1.

Q: What are some potential causes of the flakiness issue?

A: Some potential causes of the flakiness issue include:

DAP Server Configuration: The DAP server's configuration might be causing the issue. For example, the server might not be configured to receive breakpoint events, or the configuration might be incorrect.
Test Case Implementation: The test case implementation might be causing the issue. For example, the test case might be setting the breakpoint incorrectly, or the test case might be expecting the wrong number of breakpoint events.
LLDB Build Configuration: The LLDB build configuration might be causing the issue. For example, the build configuration might be incorrect, or the build might be missing some necessary dependencies.

Q: What are some potential solutions to resolve the flakiness issue?

A: Some potential solutions to resolve the flakiness issue include:

Verify DAP Server Configuration: Verify that the DAP server is correctly configured to receive breakpoint events.
Review Test Case Implementation: Review the test case implementation to ensure that it is setting the breakpoint correctly and expecting the correct number of breakpoint events.
Check LLDB Build Configuration: Check the LLDB build configuration to ensure that it is correct and that all necessary dependencies are included.

Q: How can I help resolve the flakiness issue?

A: You can help resolve the flakiness issue by:

Providing More Information: Provide more information about the issue, such as the test case's behavior and the DAP server's configuration.
Collaborating with Other Teams: Collaborate with other teams to gather more information about the issue and potential solutions.
Helping with Debugging: Help with debugging the issue by using debugging tools to capture more information about the test case's behavior.

Q: What are some best practices for writing test cases?

A: Some best practices for writing test cases include:

Writing Clear and Concise Test Cases: Write clear and concise test cases that are easy to understand and maintain.
Using Meaningful Test Case Names: Use meaningful test case names that describe the test case's purpose and behavior.
Including Relevant Test Case Data: Include relevant test case data, such as input and expected output, to help with debugging and testing.

Q: How can I get involved in the `lldb-dap` project?

A: You can get involved in the lldb-dap project by:

Contributing Code: Contribute code to the project by fixing bugs, adding new features, or improving existing code.
Reporting Issues: Report issues with the project, such as bugs or test case failures.
Collaborating with Other Teams: Collaborate with other teams to gather more information about the project and potential solutions.

Q: Where can I find more information about the `lldb-dap` project?

A: You can find more information about the lldb-dap project by:

Visiting the Project Website: Visit the project website to learn more about the project and its goals.
Reading the Project Documentation: Read the project documentation to learn more about the project's architecture and functionality.
Joining the Project Mailing List: Join the project mailing list to stay up-to-date with the latest project news and developments.