Stage‑level environment variables in Declarative Pipeline: Do they propagate to the post section?

Direct Answer

Yes, but only on Jenkins 2.400 and later. Stage‑level environment variables are visible inside that stage’s post block starting with Jenkins 2.400. On earlier releases (2.300–2.399 and older) they are not injected, so references in post resolve to empty or undefined values.

Version‑specific Behavior

• Jenkins ≥ 2.400: The stage scope is extended to cover post sections. Variables defined in stage('X') { environment { VAR = 'value' } } are available in post { always { echo "${VAR}" } }.
• Jenkins < 2.400: The post block runs in a narrower scope that only inherits pipeline‑level and global environment variables. Stage‑level variables are absent.

The change was introduced as part of the Declarative Pipeline 1.9 / Pipeline: Declarative 2.0 work that shipped with Jenkins 2.400. It is not back‑ported.

Implications for Cleanup Logic

If your post block relies on a stage‑level variable (e.g., a dynamically generated artifact path, a feature flag, or a credentials ID), the script will behave differently depending on the Jenkins version:

• Missing variable: sh "rm -f ${ARTIFACT_PATH}" expands to rm -f (no argument), potentially deleting nothing or, worse, the current directory if the command is malformed.
• Conditional logic: when { expression { return env.DEPLOY == 'true' } } inside post will always evaluate false on older versions.
• Credential references: withCredentials([...]) that pull a secret from a stage‑level variable will fail with “variable not set” errors.

Workarounds for pre‑2.400 instances include promoting the variable to pipeline level, writing the value to a file in the workspace and reading it in post, or using a shared library to stash the value in a global map.

Verification Steps

1. Create a minimal Jenkinsfile:

   pipeline {
     agent any
     stages {
       stage('Test') {
         environment {
           STAGE_VAR = 'stage-value'
         }
         steps {
           echo "In steps: ${STAGE_VAR}"
         }
         post {
           always {
             echo "In post: ${STAGE_VAR}"
           }
         }
       }
     }
   }

2. Run the pipeline on the target Jenkins version.
3. Check the console output for the In post: line.
   • If it prints In post: stage-value, propagation works (Jenkins ≥ 2.400).
   • If it prints In post: (empty) or throws a missing‑property exception, propagation is absent (Jenkins < 2.400).

One Diagnostic Detail Needed

What is the exact Jenkins version (core + Declarative plugin) you are targeting? The recommendation changes completely between 2.399 and 2.400, so confirming the version lets me confirm whether you can rely on propagation or must apply a workaround.