$ snakemake -j1 archive

Building DAG of jobs...
Using shell: /usr/bin/bash
Provided cores: 12
Rules claiming more threads will be scaled down.
Job counts:
        count   jobs
        1       archive
        1

[Tue Apr 21 04:13:50 2020]
rule archive:
    output: 
    jobid: 0

Traceback (most recent call last):
  File "/home/avmo/.conda/envs/eturb/lib/python3.7/site-packages/snakemake/__init__.py", line 633, in snakemake
    keepincomplete=keep_incomplete,
  File "/home/avmo/.conda/envs/eturb/lib/python3.7/site-packages/snakemake/workflow.py", line 850, in execute
    success = scheduler.schedule()
  File "/home/avmo/.conda/envs/eturb/lib/python3.7/site-packages/snakemake/scheduler.py", line 374, in schedule
    self.run(job)
  File "/home/avmo/.conda/envs/eturb/lib/python3.7/site-packages/snakemake/scheduler.py", line 393, in run
    error_callback=self._error,
  File "/home/avmo/.conda/envs/eturb/lib/python3.7/site-packages/snakemake/executors.py", line 356, in run
    super()._run(job)
  File "/home/avmo/.conda/envs/eturb/lib/python3.7/site-packages/snakemake/executors.py", line 178, in _run
    self.register_job(job)
  File "/home/avmo/.conda/envs/eturb/lib/python3.7/site-packages/snakemake/executors.py", line 171, in register_job
    job.register()
  File "/home/avmo/.conda/envs/eturb/lib/python3.7/site-packages/snakemake/jobs.py", line 938, in register
    self.dag.workflow.persistence.started(self)
  File "/home/avmo/.conda/envs/eturb/lib/python3.7/site-packages/snakemake/persistence.py", line 161, in started
    f,
  File "/home/avmo/.conda/envs/eturb/lib/python3.7/site-packages/snakemake/persistence.py", line 304, in _record
    recpath = self._record_path(subject, id)
  File "/home/avmo/.conda/envs/eturb/lib/python3.7/site-packages/snakemake/persistence.py", line 362, in _record_path
    b64id = ["@" + s for s in b64id[:-1]] + [b64id[-1]]
IndexError: list index out of range

import os

def file_name_generator(base):
    if os.path.exists(base):
        return "my_file.tar"
    else:
        return ""

rule clean:
    params:
        tarball = file_name_generator("source.txt")
    shell:
        """
        if [ "{params.tarball}" ] && [  ! -f "{params.tarball}" ]; then
            echo "ERROR: Archive {params.tarball} not found. Refusing to clean simulation files! Run 'snakemake archive'"
            exit 1
        fi
        rm -f source.txt
        """
rule archive:
    params: msg = "Hello"
    output: file_name_generator("source.txt")
    shell: "tar -cf {output} source.txt"