Get the Commit of the Last Successful Build in Azure Pipelines

The idea is to use Azure Devops CLI directly in the Pipeline Yaml

First, we configure Devops CLI

# Set Azure Devops default settings
- bash: az devops configure --defaults organization=$(System.TeamFoundationCollectionUri) project=$(System.TeamProject)
  displayName: 'Configure Azure DevOps organization and project'

Then we can query the pipelines API (providing the auth token)

# Get last successfully commit infos from Azure Devops
- bash: |
    LAST_SHA=$(az pipelines build list --branch $(Build.SourceBranchName) --definition-ids $(System.DefinitionId) --result succeeded --top 1 --query "[0].triggerInfo.\"ci.sourceSha\"")
    echo "Last successful commit SHA: $LAST_SHA"
    echo "##vso[task.setvariable variable=BASE_SHA]$LAST_SHA"
  displayName: 'Get last successful commit SHA'
  env:
    AZURE_DEVOPS_EXT_PAT: $(System.AccessToken)

We can target a specific build, in this example we specified:

The branch (--branch)
The pipeline Id (--definition-ids)
The result type (--result)
The number of result (-top)

By default the command returns an entire JSON object with all the information. But we can narrow it down to the desired result with the --query param that uses JMESPath format (more details)

Finally we extract the result in a common custom variable named BASE_SHA used later by nx affected commands

An example with a default SHA in case no commit is found:

azure-pipelines.yml
trigger:
  - main
pr:
  - main

variables:
  CI: 'true'
  NX_BRANCH: $(Build.SourceBranchName)
  DEFAULT_BASE_SHA: $(git rev-parse HEAD~1)
  HEAD_SHA: $(git rev-parse HEAD)

jobs:
  - job: main
    pool:
      vmImage: 'ubuntu-latest'
    steps:
      # Set Azure Devops CLI default settings
      - bash: az devops configure --defaults organization=$(System.TeamFoundationCollectionUri) project=$(System.TeamProject)
      displayName: 'Set default Azure DevOps organization and project'

      # Get last successfull commit from Azure Devops CLI
      - bash: |
          LAST_SHA=$(az pipelines build list --branch $(Build.SourceBranchName) --definition-ids $(System.DefinitionId) --result succeeded --top 1 --query "[0].triggerInfo.\"ci.sourceSha\"")
          if [ -z "$LAST_SHA" ]
          then
            LAST_SHA=$DEFAULT_BASE_SHA
          fi
          echo "Last successful commit SHA: $LAST_SHA"
          echo "##vso[task.setvariable variable=BASE_SHA]$LAST_SHA"
        displayName: 'Get last successful commit SHA'
        env:
          AZURE_DEVOPS_EXT_PAT: $(System.AccessToken)

      - script: npm ci

      - script: npx nx format:check

      - script: npx nx affected --base=$(BASE_SHA) -t lint --parallel=3
      - script: npx nx affected --base=$(BASE_SHA) -t test --parallel=3 --ci --code-coverage
      - script: npx nx affected --base=$(BASE_SHA) -t build --parallel=3