Task 9: Initialize the default main branch, if it does not exist already.

Task 9: Initialize the main branch (if it doesn’t exist) and create a pull request-triggered pipeline for .NET Core build

Step 1: Initialize the main Branch

In your Azure DevOps Project (Project1), navigate to Repos.

In the left menu, click Files.

If you see a message like “This repository is empty,” click Initialize.

Create a README.md file (or another file) and set the default branch name to main.

Click Initialize.

If the main branch already exists, you can skip this step.

Step 2: Create a New Branch for the Pipeline

In Repos > Files, click on the Branches tab.

Click New branch.

Enter:

Branch name: azure-pipelinesT

Based on: main

Click Create.

This creates a new branch named azure-pipelinesT from main.

Step 3: Create the Pipeline YAML File in the New Branch

Switch to the azure-pipelinesT branch.

In Files, click New file.

Name the file: azure-pipelines.yml.

Step 4: Write the YAML Pipeline for .NET Core Build

Here’s a sample YAML file:

trigger: none

pr:

branches:

include:

- main

pool:

vmImage: 'windows-latest'

variables:

buildConfiguration: 'Release'

steps:

- task: UseDotNet@2

displayName: 'Install .NET Core SDK'

inputs:

packageType: 'sdk'

version: '8.x' # Or specify the exact version of .NET Core SDK you need

installationPath: $(Agent.ToolsDirectory)/dotnet

- script: dotnet build src --configuration $(buildConfiguration)

displayName: 'Build .NET Core project'

This pipeline:

Runs only when a pull request is created or updated targeting the main branch.

Uses the windows-latest agent.

Installs the .NET SDK and builds the project in the src directory.

Step 5: Commit the Pipeline File

In the bottom commit message box:

Message: Add PR-triggered pipeline for .NET Core build

Ensure the branch is set to azure-pipelinesT.

Click Commit.

Step 6: Create the Pipeline in Azure DevOps

In the left menu, click Pipelines.

Click New pipeline.

Select:

Azure Repos Git.

Select your repository.

Choose Existing Azure Pipelines YAML file.

In the branch selector, choose the azure-pipelinesT branch.

Select the YAML file path (azure-pipelines.yml).

Click Continue and Run to validate.

Step 7: Test the Pipeline Trigger

Create a new branch (e.g., feature/test-pr).

Push a commit and create a pull request targeting main.

Verify that the pipeline runs automatically for this PR in Pipelines.