Best Practices for Avoiding CI Failures

Oct 13, 2025 by wbrum.org 20 views

Understanding the Issue

Continuous Integration (CI) is a crucial aspect of modern software development, ensuring that code changes are thoroughly tested before they are merged into the main branch. However, when dealing with complex workflows and multiple integration tests, issues can arise. In this article, we will delve into a specific scenario where a CI failure occurs during the integration test of a pull request (PR) due to conflicting results.

The Problem: Conflicting Results

When a developer pushes a branch containing changes to the results, it triggers an integration test workflow. Before the integration test completes, the developer opens a pull request, which in turn triggers another integration test workflow. The push-triggered integration test workflow finishes and commits updated results to the branch, updating the branch head to a new commit (Commit B). Meanwhile, the pull-request integration test, still running based on the original commit (Commit A), fails during the pull step because it detects that the branch head has changed (now Commit B).

Recreating the Issue

To reproduce this issue, follow these steps:

Step 1: Push a Branch with Changes

Push a branch that contains changes to the results. This creates a new commit, which we'll refer to as Commit A.

Step 2: Open a Pull Request

Before the integration test triggered by the push completes, open a pull request. This will trigger another integration test workflow that starts with Commit A.

Step 3: Integration Test Workflow Completes

The integration test workflow triggered by the push finishes and commits updated results to the branch. This updates the branch head to a new commit, which we'll refer to as Commit B.

Step 4: Pull-Request Integration Test Fails

The pull-request integration test, still running based on Commit A, fails during the pull step because it detects that the branch head has changed (now Commit B).

Visualizing the Issue

To better understand the sequence of events leading to the CI failure, let's visualize the process using a Mermaid diagram:

sequenceDiagram
    participant Dev as Developer
    participant PW as Push Workflow
    participant PR as Pull Request Workflow

    Dev->>PW: Push branch (Commit A)
    PW->>PW: Start push-triggered integration test
    Dev->>PR: Open pull request 
    PR->>PR: Start PR triggered integration test
    PW->>PW: Push-triggered integration test completes
    PW->>Dev: Commit updated results (Commit B)
    PR->>PR: Attempt update from Commit A
    PR->>Dev: Fail due to branch head change

Resolving the Issue

To resolve this issue, we need to ensure that the integration test workflow triggered by the pull request is aware of the updated branch head. One possible solution is to use a more robust branching strategy, such as feature branches, which can help avoid conflicts between different integration test workflows.

Another approach is to use a more advanced CI/CD tool that can handle complex workflows and multiple integration tests. This can include features such as:

Branch management: The ability to manage multiple branches and their corresponding integration test workflows.
Workflow orchestration: The ability to orchestrate complex workflows and ensure that integration tests are run in the correct order.
Conflict resolution: The ability to detect and resolve conflicts between different integration test workflows.

Best Practices for Avoiding CI Failures

To avoid CI failures during PR integration tests, follow these best practices:

Use feature branches: Use feature branches to isolate changes and avoid conflicts between different integration test workflows.
Use a robust branching strategy: Use a branching strategy that can handle complex workflows and multiple integration tests.
Use a more advanced CI/CD tool: Use a CI/CD tool that can handle complex workflows and multiple integration tests.
Test thoroughly: Test your code thoroughly before merging it into the main branch.
Monitor your CI/CD pipeline: Monitor your CI/CD pipeline to detect and resolve issues quickly.

Understanding the Issue

The Problem: Conflicting Results

Recreating the Issue

To reproduce this issue, follow these steps:

Step 1: Push a Branch with Changes

Push a branch that contains changes to the results. This creates a new commit, which we'll refer to as Commit A.

Step 2: Open a Pull Request

Before the integration test triggered by the push completes, open a pull request. This will trigger another integration test workflow that starts with Commit A.

Step 3: Integration Test Workflow Completes

The integration test workflow triggered by the push finishes and commits updated results to the branch. This updates the branch head to a new commit, which we'll refer to as Commit B.

Step 4: Pull-Request Integration Test Fails

The pull-request integration test, still running based on Commit A, fails during the pull step because it detects that the branch head has changed (now Commit B).

Visualizing the Issue

To better understand the sequence of events leading to the CI failure, let's visualize the process using a Mermaid diagram:

sequenceDiagram
    participant Dev as Developer
    participant PW as Push Workflow
    participant PR as Pull Request Workflow

    Dev->>PW: Push branch (Commit A)
    PW->>PW: Start push-triggered integration test
    Dev->>PR: Open pull request 
    PR->>PR: Start PR triggered integration test
    PW->>PW: Push-triggered integration test completes
    PW->>Dev: Commit updated results (Commit B)
    PR->>PR: Attempt update from Commit A
    PR->>Dev: Fail due to branch head change

Resolving the Issue

Another approach is to use a more advanced CI/CD tool that can handle complex workflows and multiple integration tests. This can include features such as:

Branch management: The ability to manage multiple branches and their corresponding integration test workflows.
Workflow orchestration: The ability to orchestrate complex workflows and ensure that integration tests are run in the correct order.
Conflict resolution: The ability to detect and resolve conflicts between different integration test workflows.

Best Practices for Avoiding CI Failures

To avoid CI failures during PR integration tests, follow these best practices:

Use feature branches: Use feature branches to isolate changes and avoid conflicts between different integration test workflows.
Use a robust branching strategy: Use a branching strategy that can handle complex workflows and multiple integration tests.
Use a more advanced CI/CD tool: Use a CI/CD tool that can handle complex workflows and multiple integration tests.
Test thoroughly: Test your code thoroughly before merging it into the main branch.
Monitor your CI/CD pipeline: Monitor your CI/CD pipeline to detect and resolve issues quickly.

Q&A: CI Failure During PR Integration Test

Q: What is the root cause of the CI failure during PR integration test?

A: The root cause of the CI failure during PR integration test is the conflict between the push-triggered integration test workflow and the pull-request integration test workflow. The push-triggered integration test workflow updates the branch head to a new commit, while the pull-request integration test workflow is still running based on the original commit.

Q: How can I avoid CI failures during PR integration tests?

A: To avoid CI failures during PR integration tests, use feature branches to isolate changes and avoid conflicts between different integration test workflows. Use a robust branching strategy and a more advanced CI/CD tool that can handle complex workflows and multiple integration tests.

Q: What are some best practices for avoiding CI failures during PR integration tests?

A: Some best practices for avoiding CI failures during PR integration tests include:

Using feature branches to isolate changes and avoid conflicts between different integration test workflows.
Using a robust branching strategy that can handle complex workflows and multiple integration tests.
Using a more advanced CI/CD tool that can handle complex workflows and multiple integration tests.
Testing your code thoroughly before merging it into the main branch.
Monitoring your CI/CD pipeline to detect and resolve issues quickly.

Q: Can I use a more advanced CI/CD tool to resolve the issue?

A: Yes, you can use a more advanced CI/CD tool to resolve the issue. Some popular CI/CD tools that can handle complex workflows and multiple integration tests include Jenkins, Travis CI, and CircleCI.

Q: How can I visualize the sequence of events leading to the CI failure?

A: You can visualize the sequence of events leading to the CI failure using a Mermaid diagram. This can help you understand the issue and identify the root cause.

Q: What are some common mistakes that can lead to CI failures during PR integration tests?

A: Some common mistakes that can lead to CI failures during PR integration tests include:

Not using feature branches to isolate changes and avoid conflicts between different integration test workflows.
Not using a robust branching strategy that can handle complex workflows and multiple integration tests.
Not testing your code thoroughly before merging it into the main branch.
Not monitoring your CI/CD pipeline to detect and resolve issues quickly.

By following these best practices and using a more advanced CI/CD tool, you can avoid CI failures during PR integration tests and ensure that your code is thoroughly tested before it is merged into the main branch.