Identical Steps in Serial Workflow Cause Incorrect Execution and Status

[Alputer]

Description

When a serial workflow contains two identical steps with the same name, the second occurrence is not executed, and its status is incorrectly set to "stopped." However, the overall workflow still succeeds, which is unintuitive.

Expected Behavior

• Each step in the workflow should execute as expected, even if there are identical steps.
• If a step is skipped due to caching or another mechanism, its status should accurately reflect the reason.

Observed Behavior

• The second instance of an identical step is not executed.
• Its status is incorrectly marked as "stopped."
• The workflow completes successfully despite the skipped step.

Possible Cause

This issue may be related to workflow caching. When the same step reappears later in the workflow, it might be skipped due to caching, but its status is not correctly updated. Alternatively, a preprocessing or postprocessing mechanism might be handling it incorrectly.

Suggested Solution

A simple solution could be to disallow steps from having the same name, which would:

• Prevent this issue and ensure correct execution behavior.
• Reduce the likelihood of future bugs caused by identical step names leading to unexpected behavior.

How to reproduce

1. cd reana-demo-root6-roofit
2. Update reana.yaml

version: 0.6.0
inputs:
  files:
    - code/gendata.C
    - code/fitdata.C
  parameters:
    events: 20000
    data: results/data.root
    plot: results/plot.png
workflow:
  type: serial
  specification:
    steps:
      - name: gendata
        environment: 'docker.io/reanahub/reana-env-root6:6.18.04'
        kubernetes_memory_limit: '256Mi'
        commands:
        - mkdir -p results && root -b -q 'code/gendata.C(${events},"${data}")'
      - name: gendata
        environment: 'docker.io/reanahub/reana-env-root6:6.18.04'
        kubernetes_memory_limit: '256Mi'
        commands:
        - mkdir -p results && root -b -q 'code/gendata.C(${events},"${data}")'
outputs:
  files:
    - results/plot.png
tests:
  files:
    - tests/serial/log-messages.feature
    - tests/serial/run-duration.feature
    - tests/serial/workspace-files.feature

• Run reana-client run -w roofit and wait a minute for workflow to finish.

• Run reana-client status -w roofit

$ reana-client status -w roofit
NAME       RUN_NUMBER   CREATED               STARTED               ENDED                 STATUS     PROGRESS
roofit   1            2025-03-04T09:03:41   2025-03-04T09:03:53   2025-03-04T09:03:59   finished   1/2

• Run reana-client logs -w roofit

$ reana-client logs -w roofit
==> Workflow engine logs
2025-03-04 09:03:44,527 | werkzeug | MainThread | WARNING |  * Debugger is active!
2025-03-04 09:03:53,473 | root | MainThread | INFO | Publishing step:0, cmd: mkdir -p results && root -b -q 'code/gendata.C(20000,"results/data.root")', total steps 2 to MQ
2025-03-04 09:03:59,560 | root | MainThread | INFO | Publishing step:1, cmd: mkdir -p results && root -b -q 'code/gendata.C(20000,"results/data.root")', total steps 2 to MQ
2025-03-04 09:03:59,626 | root | MainThread | WARNING | Termination signal 15 received. Workflow interrupted ...
2025-03-04 09:03:59,654 | root | Thread-10 (process_request_thread) | WARNING | Container job failed, error: None



==> Job logs
==> Step: gendata
==> Workflow ID: c367828d-5b9e-4473-b548-9b343089d802
==> Compute backend: Kubernetes
==> Job ID: reana-run-job-7b89f396-f5dc-4b30-9eb0-3cb587599c15
==> Docker image: docker.io/reanahub/reana-env-root6:6.18.04
==> Command: mkdir -p results && root -b -q 'code/gendata.C(20000,"results/data.root")'
==> Status: finished
==> Started: 2025-03-04T09:03:53
==> Finished: 2025-03-04T09:03:55
==> Logs:
   ------------------------------------------------------------
  | Welcome to ROOT 6.18/04                  https://root.cern |
  |                               (c) 1995-2019, The ROOT Team |
  | Built for linuxx8664gcc on Jan 08 2020, 14:10:00           |
  | From tags/v6-18-04@v6-18-04                                |
  | Try '.help', '.demo', '.license', '.credits', '.quit'/'.q' |
   ------------------------------------------------------------


Processing code/gendata.C(20000,"results/data.root")...

RooFit v3.60 -- Developed by Wouter Verkerke and David Kirkby 
                Copyright (C) 2000-2013 NIKHEF, University of California & Stanford University
                All rights reserved, please read http://roofit.sourceforge.net/license.txt

[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooAddPdf::model
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooChebychev::bkg
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::x
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::a0
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::a1
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::nbkg
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooAddPdf::sig
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooGaussian::sig1
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::mean
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::sigma1
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::sig1frac
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing RooRealVar::nsig
[#1] INFO:ObjectHandling -- RooWorkspace::import(w) importing dataset modelData

RooWorkspace(w) workspace contents

variables
---------
(a0,a1,mean,nbkg,nsig,sig1frac,sigma1,x)

p.d.f.s
-------
RooChebychev::bkg[ x=x coefList=(a0,a1) ] = 1
RooAddPdf::model[ nbkg * bkg + nsig * sig ] = 1
RooAddPdf::sig[ sig1frac * sig1 ] = 1
RooGaussian::sig1[ x=x mean=mean sigma=sigma1 ] = 1

datasets
--------
RooDataSet::modelData(x)


==> Step: gendata
==> Workflow ID: c367828d-5b9e-4473-b548-9b343089d802
==> Compute backend: Kubernetes
==> Job ID: reana-run-job-3d08a336-f103-4c86-9137-0701b9ca7ebc
==> Docker image: docker.io/reanahub/reana-env-root6:6.18.04
==> Command: mkdir -p results && root -b -q 'code/gendata.C(20000,"results/data.root")'
==> Status: stopped
==> Started: 2025-03-04T09:03:59
==> Logs:
Container job failed, error: None