Useful diagnostics regarding common mistakes in pipeline scripts are lost

[hasselmm]

Jenkins and plugins versions report

Environment

Jenkins: 2.530
---
Office-365-Connector:5.2.0
PrioritySorter:905.v35c21f62f980
antisamy-markup-formatter:173.v680e3a_b_69ff3
apache-httpcomponents-client-4-api:4.5.14-269.vfa_2321039a_83
apache-httpcomponents-client-5-api:5.5-170.v023de017ccd7
archived-artifact-url-viewer:1.1
asm-api:9.8-163.vb_2a_96d3f9c3c
authentication-tokens:1.144.v5ff4a_5ec5c33
azure-sdk:248.v0c922122245c
bitbucket:273.v7b_535e8f11c2
bootstrap5-api:5.3.8-895.v4d0d8e47fea_d
bouncycastle-api:2.30.1.82-277.v70ca_0b_877184
branch-api:2.1253.v6e7f7519f710
build-timeout:1.38
caffeine-api:3.2.2-178.v353b_8428ed56
checks-api:373.vfe7645102093
cloudbees-bitbucket-branch-source:936.4.4
cloudbees-folder:6.1045.vb_ddd55e2d03f
command-launcher:123.v37cfdc92ef67
commons-compress-api:1.28.0-1
commons-httpclient3-api:3.1-3
commons-lang3-api:3.19.0-104.v12125f33a_255
commons-text-api:1.14.0-194.v804a_dc3a_1b_d8
conditional-buildstep:1.5.0
credentials:1447.v4cb_b_539b_5321
credentials-binding:702.vfe613e537e88
dark-theme:574.va_19f05d54df5
data-tables-api:2.3.4-1413.va_57c35d0a_9ec
display-url-api:2.217.va_6b_de84cc74b_
docker-commons:457.v0f62a_94f11a_3
dtkit-api:3.0.3
durable-task:605.v9a_b_9040c9970
echarts-api:6.0.0-1165.vd1283a_3e37d4
eddsa-api:0.3.0.1-19.vc432d923e5ee
email-ext:1925.v1598902b_58dd
external-monitor-job:223.vb_fddcf42c9b_3
favorite:2.253.v9b_413168133b_
file-operations:353.vf3b_9b_a_f1f7f7
font-awesome-api:7.0.1-872.vb_679b_2c95492
generic-webhook-trigger:2.4.1
git:5.7.0
git-client:6.4.0
git-server:137.ve0060b_432302
github-api:1.330-492.v3941a_032db_2a_
gitlab-api:5.8.1-106.vef1de800710e
gitlab-branch-source:724.v6e30226050b_3
gitlab-logo:221.v4041f5e65573
gitlab-plugin:1.9.9
gson-api:2.13.2-173.va_a_092315913c
handy-uri-templates-2-api:2.1.8-36.v85e4cb_234a_13
htmlpublisher:427
instance-identity:203.v15e81a_1b_7a_38
ionicons-api:94.vcc3065403257
jackson2-api:2.20.0-411.v6ef8fdee4fe9
jakarta-activation-api:2.1.3-2
jakarta-mail-api:2.1.3-3
javax-activation-api:1.2.0-8
javax-mail-api:1.6.2-11
jaxb:2.3.9-133.vb_ec76a_73f706
jdk-tool:83.v417146707a_3d
jersey2-api:2.47-165.ve7809a_3e87e0
jjwt-api:0.11.5-120.v0268cf544b_89
jnr-posix-api:3.1.20-166.v50a_50932c65b_
jobcacher:732.ve164e3059a_a_a_
joda-time-api:2.14.0-149.v1c3ce991d1b_9
jquery:1.12.4-3
jquery3-api:3.7.1-619.vdb_10e002501a_
jsch:0.2.16-95.v3eecb_55fa_b_78
json-api:20250517-173.v596efb_962a_31
json-path-api:2.9.0-190.veefca_05d5477
jsoup:1.21.2-66.v6ea_38164b_8a_2
junit:1359.v71188fea_0df5
junit-attachments:330.v25180b_263160
junit-realtime-test-reporter:166.v889e7b_0e23a_a_
ldap:793.v754d6b_41b_ea_4
lockable-resources:1412.v3f305a_fb_a_117
mailer:522.va_995fa_cfb_8b_d
mapdb-api:1.0.9-44.va_1e1310c9118
matrix-auth:3.2.8
matrix-project:858.vb_b_eb_9a_7ea_99e
mercurial:1323.ve69d2a_db_8a_b_d
metrics:4.2.33-484.v2fcd689980d1
mina-sshd-api-common:2.16.0-167.va_269f38cc024
mina-sshd-api-core:2.16.0-167.va_269f38cc024
netty-api:4.1.118.Final-9.v776038d601a_7
okhttp-api:4.12.0-195.vc02552c04ffd
oss-symbols-api:392.v27a_482d90083
pam-auth:1.12
parameterized-trigger:873.v8b_e37dd8418f
pipeline-build-step:571.v08a_fffd4b_0ce
pipeline-github-lib:65.v203688e7727e
pipeline-graph-analysis:245.v88f03631a_b_21
pipeline-graph-view:646.va_da_a_047edca_c
pipeline-groovy-lib:766.v2b_e08c2e6ff2
pipeline-input-step:534.v352f0a_e98918
pipeline-keep-running-step:1.3
pipeline-milestone-step:138.v78ca_76831a_43
pipeline-model-api:2.2273.v643f36ed9e94
pipeline-model-definition:2.2273.v643f36ed9e94
pipeline-model-extensions:2.2273.v643f36ed9e94
pipeline-rest-api:2.38
pipeline-stage-step:322.vecffa_99f371c
pipeline-stage-tags-metadata:2.2273.v643f36ed9e94
pipeline-stage-view:2.38
pipeline-utility-steps:2.20.0
plain-credentials:199.v9f8e1f741799
plugin-usage-plugin:4.10
plugin-util-api:6.1192.v30fe6e2837ff
publish-over:0.22
pubsub-light:1.19
pyenv-pipeline:2.1.2
resource-disposer:0.25
run-condition:243.v3c3f94e46a_8b_
scm-api:710.v7b_a_484d81f45
script-security:1378.vf25626395f49
snakeyaml-api:2.3-125.v4d77857a_b_402
sse-gateway:1.28
ssh-agent:386.v36cc0c7582f0
ssh-credentials:361.vb_f6760818e8c
ssh-slaves:3.1071.v0d059c7b_c555
sshd:3.374.v19b_d59ce6610
structs:353.v261ea_40a_80fb_
test-results-aggregator:3.2
test-results-analyzer:309.vda_3a_a_f100542
theme-manager:319.v9193461f9671
timestamper:1.30
token-macro:477.vd4f0dc3cb_cf1
trilead-api:2.209.v0e69b_c43c245
variant:70.va_d9f17f859e0
workflow-aggregator:608.v67378e9d3db_1
workflow-api:1384.vdc05a_48f535f
workflow-basic-steps:1098.v808b_fd7f8cf4
workflow-cps:4209.v83c4e257f1e9
workflow-durable-task-step:1464.v2d3f5c68f84c
workflow-job:1549.vc8d7f497b_22f
workflow-multibranch:821.vc3b_4ea_780798
workflow-scm-step:452.vdf1ca_c8d3a_87
workflow-step-api:710.v3e456cc85233
workflow-support:989.va_20a_1a_57710a_
ws-cleanup:0.49  ```
</details>

### What Operating System are you using (both controller, and any agents involved in the problem)?

Unrelated

### Reproduction steps

Run this pipeline script in Jenkins:

```groovy
targets = [1, 2, 3]

def currentTarget() {
  return targets[0]
}

pipeline {
  agent any
  
  stages {
      stage("Minimal Test Case") {
          steps {
              echo currentTarget()
          }
      }
  }
}

Expected Results

This diagnostics from Jenkins is presented to me, the user:

Did you forget the def keyword? WorkflowScript seems to be setting a field named targets (to a value of type ArrayList) which could lead to memory leaks or other issues.

Actual Results

The diagnostics is not shown, but burried in the plain text log:

[2025-10-10T09:24:08.542Z] Started by user Mathias Hasselmann
[2025-10-10T09:24:08.587Z] [Pipeline] Start of Pipeline
[2025-10-10T09:24:08.604Z] Did you forget the `def` keyword? WorkflowScript seems to be setting a field named targets (to a value of type ArrayList) which could lead to memory leaks or other issues.
[2025-10-10T09:24:08.702Z] [Pipeline] node
[2025-10-10T09:24:08.721Z] Running on macstudio-macos in /opt/Jenkins/workspace/Pipeline Test
[2025-10-10T09:24:08.734Z] [Pipeline] {
[2025-10-10T09:24:08.783Z] [Pipeline] stage
[2025-10-10T09:24:08.791Z] [Pipeline] { (Minimal Test Case)
[2025-10-10T09:24:08.848Z] [Pipeline] echo
[2025-10-10T09:24:08.853Z] 1
[2025-10-10T09:24:08.860Z] [Pipeline] }
[2025-10-10T09:24:08.894Z] [Pipeline] // stage
[2025-10-10T09:24:08.905Z] [Pipeline] }
[2025-10-10T09:24:08.945Z] [Pipeline] // node
[2025-10-10T09:24:08.958Z] [Pipeline] End of Pipeline
[2025-10-10T09:24:08.987Z] Finished: SUCCESS

Anything else?

No response

Are you interested in contributing a fix?

No response