Parameterize Incrementalist base branch for Azure DevOps pipelines (akkadotnet#7791)

* Parameterize Incrementalist base branch for Azure DevOps pipelines

- Add dynamic incrementalist.baseBranch variable to pipeline templates
- Use System.PullRequest.TargetBranch for PR builds
- Default to 'dev' for non-PR builds
- Update all Incrementalist commands to use --branch parameter

This allows PRs targeting version branches (e.g., v1.5) to correctly
compare against their target branch instead of always using dev,
avoiding unnecessary full builds.

* Fix Incrementalist base branch detection for Azure DevOps PRs

- Use PowerShell script to extract branch name from System.PullRequest.TargetBranch
- Strip 'refs/heads/' prefix from target branch reference
- Set IncrementalistBaseBranch variable dynamically at runtime
- Update all Incrementalist commands to use the new variable

This fixes the issue where PR builds always used 'dev' as the base branch
even when targeting version branches like v1.5.

Author: Aaronontheweb

build-system/azure-pipeline.mntr-template.yaml

@@ -20,6 +20,19 @@ jobs:
         inputs:
           packageType: 'sdk'
           useGlobalJson: true
+      
+      # Set the Incrementalist base branch based on PR target branch
+      - pwsh: |
+          if ('$(Build.Reason)' -eq 'PullRequest') {
+            # Extract branch name from refs/heads/branch format
+            $targetBranch = '$(System.PullRequest.TargetBranch)'.Replace('refs/heads/', '')
+            Write-Host "PR detected - using base branch: $targetBranch"
+            Write-Host "##vso[task.setvariable variable=IncrementalistBaseBranch]$targetBranch"
+          } else {
+            Write-Host "Not a PR - using default base branch: dev"
+            Write-Host "##vso[task.setvariable variable=IncrementalistBaseBranch]dev"
+          }
+        displayName: 'Set Incrementalist base branch'
 
       - script: dotnet tool restore
         displayName: 'Restore dotnet tools'

build-system/azure-pipeline.template.yaml

@@ -27,6 +27,19 @@ jobs:
         inputs:
           packageType: 'sdk'
           useGlobalJson: true
+      
+      # Set the Incrementalist base branch based on PR target branch
+      - pwsh: |
+          if ('$(Build.Reason)' -eq 'PullRequest') {
+            # Extract branch name from refs/heads/branch format
+            $targetBranch = '$(System.PullRequest.TargetBranch)'.Replace('refs/heads/', '')
+            Write-Host "PR detected - using base branch: $targetBranch"
+            Write-Host "##vso[task.setvariable variable=IncrementalistBaseBranch]$targetBranch"
+          } else {
+            Write-Host "Not a PR - using default base branch: dev"
+            Write-Host "##vso[task.setvariable variable=IncrementalistBaseBranch]dev"
+          }
+        displayName: 'Set Incrementalist base branch'
 
       - script: dotnet tool restore
         displayName: 'Restore dotnet tools'

build-system/pr-validation.yaml

@@ -59,7 +59,7 @@ jobs:
       name: "netfx_tests_windows"
       displayName: ".NET Framework Unit Tests (Windows)"
       vmImage: "windows-latest"
-      command: "dotnet incrementalist run --config .incrementalist/testsOnly.json -- test -c Release --no-build --framework net48 --logger:trx --results-directory TestResults"
+      command: "dotnet incrementalist run --config .incrementalist/testsOnly.json --branch $(IncrementalistBaseBranch) -- test -c Release --no-build --framework net48 --logger:trx --results-directory TestResults"
       outputDirectory: "TestResults"
       artifactName: "netfx_tests_windows-$(Build.BuildId)"
 
@@ -80,7 +80,7 @@ jobs:
       name: "net_tests_windows"
       displayName: ".NET Unit Tests (Windows)"
       vmImage: "windows-latest"
-      command: "dotnet incrementalist run --config .incrementalist/testsOnly.json -- test -c Release --no-build --framework net8.0 --logger:trx --results-directory TestResults"
+      command: "dotnet incrementalist run --config .incrementalist/testsOnly.json --branch $(IncrementalistBaseBranch) -- test -c Release --no-build --framework net8.0 --logger:trx --results-directory TestResults"
       outputDirectory: "TestResults"
       artifactName: "net_tests_windows-$(Build.BuildId)"
 
@@ -89,7 +89,7 @@ jobs:
       name: "net_tests_linux"
       displayName: ".NET Unit Tests (Linux)"
       vmImage: "ubuntu-latest"
-      command: "dotnet incrementalist run --config .incrementalist/testsOnly.json -- test -c Release --no-build --framework net8.0 --logger:trx --results-directory TestResults"
+      command: "dotnet incrementalist run --config .incrementalist/testsOnly.json --branch $(IncrementalistBaseBranch) -- test -c Release --no-build --framework net8.0 --logger:trx --results-directory TestResults"
       outputDirectory: "TestResults"
       artifactName: "net_tests_linux-$(Build.BuildId)"
 
@@ -98,7 +98,7 @@ jobs:
       name: "net_mntr_windows"
       displayName: ".NET Multi-Node Tests (Windows)"
       vmImage: "windows-latest"
-      command: "dotnet incrementalist run --config .incrementalist/mutliNodeOnly.json -- test -c Release --no-build --framework net8.0 --logger:trx --results-directory TestResults/multinode"
+      command: "dotnet incrementalist run --config .incrementalist/mutliNodeOnly.json --branch $(IncrementalistBaseBranch) -- test -c Release --no-build --framework net8.0 --logger:trx --results-directory TestResults/multinode"
       outputDirectory: "TestResults"
       artifactName: "net_mntr_windows-$(Build.BuildId)"
       mntrFailuresDir: 'TestResults\\multinode'