Variable values are empty after stages following the first

Question

I'm trying to access a variable from one stage in multiple consecutive stages.

In the first stage the variable has the correct value, but in all the following stages it becomes an empty string.

See also this post for more info

Any help would be appreciated

Thanks

Actually I fond more details, the variable is set to blank when de dependsOn does not point to the stage that sets the variable value, in the sample below, Stage A sets the variable, stage B depends on A and can use it, then in stage C that depends in B the variable value becomes blank.

stages:
- stage: A
  jobs:
  - job: JA
    steps:
    - script: |
        echo "This is job Foo."
        echo "##vso[task.setvariable variable=doThing;isOutput=true]Yes" #The variable doThing is set to true
      name: DetermineResult
    - script: echo $(DetermineResult.doThing)
      name: echovar
  - job: JA_2
    dependsOn: JA
    condition: eq(dependencies.JA.outputs['DetermineResult.doThing'], 'Yes')
    steps:
    - script: |
        echo "This is job Bar."

#stage B runs if DetermineResult task set doThing variable n stage A
- stage: B
  dependsOn: A
  jobs:
  - job: JB
    variables:
      varFromStageA: $[ stageDependencies.A.JA.outputs['DetermineResult.doThing'] ]
    steps:
    - bash: echo "Hello world stage B first job"
    - script: echo $(varFromStageA)

#stage B runs if DetermineResult task set doThing variable n stage A
- stage: C
  dependsOn: B
  jobs:
  - job: JC
    variables:
      varFromStageA: $[ stageDependencies.A.JA.outputs['DetermineResult.doThing'] ]
    steps:
    - bash: echo "Hello world stage B first job"
    - script: echo $(varFromStageA)    

Answer 1

You need to change Stage C to both depend on A and B. A has to be in the dependOn list in order for the stageDependencies variables to be available.

...

#stage B runs if DetermineResult task set doThing variable n stage A
- stage: C
  dependsOn: B
  jobs:

...   

...

#stage B runs if DetermineResult task set doThing variable n stage A
- stage: C
  dependsOn: 
    - A
    - B
  jobs:

...