Question

Your team's Azure DevOps YAML pipeline defines a variable 'imageTag' whose value depends on the branch that triggered the run. You need to reference this value in a template expression that conditionally includes an entire stage during pipeline compilation, before any job runs. The variable is set inside a script step using a logging command (##vso[task.setvariable]). During testing, the conditional stage never appears even when the branch condition should match. What is the root cause?

Accepted Answer

Variables set via ##vso[task.setvariable] are only available at runtime, so they cannot be evaluated by a template expression ${{ }} that resolves at compile time.

Answer

The logging command syntax requires 'isOutput=true' to make the variable visible to template expressions in the same stage.

Answer

Template expressions can read runtime variables only if the variable is declared in a variable group linked to the pipeline.

Answer

The stage condition must use the macro syntax $(imageTag) instead of a template expression to access dynamic values during compilation.