[BUG] file.comment incorrectly reports changes in test mode

[OrangeDog]

Description
When running a file.comment state the second time, no changes are made.
However, when running in test mode, it reports that it will make changes.

Setup

/etc/elasticsearch/jvm.options:
  file.comment:
    - regex: '9-:-Xlog:gc.*'
    - watch_in:
      - service: elasticsearch

Steps to Reproduce the behavior

$ sudo tail -n2 /etc/elasticsearch/jvm.options
# JDK 9+ GC logging
#9-:-Xlog:gc*,gc+age=trace,safepoint:file=/var/log/elasticsearch/gc.log:utctime,pid,tags:filecount=32,filesize=64m

$ sudo salt-call state.apply --state-output=changes
local:

Summary for local
--------------
Succeeded: 226
Failed:      0
--------------
Total states run:     226
Total run time:    26.433 s

$ sudo salt-call state.test --state-output=changes
local:
----------
          ID: /etc/elasticsearch/jvm.options
    Function: file.comment
      Result: None
     Comment: File /etc/elasticsearch/jvm.options is set to be updated
     Started: 10:58:22.192903
    Duration: 2.929 ms
     Changes:
              ----------
              /etc/elasticsearch/jvm.options:
                  updated
----------
          ID: elasticsearch_service
    Function: service.running
        Name: elasticsearch
      Result: None
     Comment: Service is set to be restarted
     Started: 10:58:22.287999
    Duration: 29.613 ms
     Changes:

Summary for local
--------------
Succeeded: 226 (unchanged=2, changed=1)
Failed:      0
--------------
Total states run:     226
Total run time:    24.190 s

Expected behavior
No changes, same as when not running in test mode.

Versions Report

salt --versions-report

(Provided by running salt --versions-report. Please also mention any differences in master/minion versions.)

Salt Version:
          Salt: 3004

Dependency Versions:
          cffi: 1.14.5
      cherrypy: Not Installed
      dateutil: 2.7.3
     docker-py: Not Installed
         gitdb: 2.0.6
     gitpython: 3.0.7
        Jinja2: 2.10.1
       libgit2: 1.3.0
      M2Crypto: 0.31.0
          Mako: Not Installed
       msgpack: 0.6.2
  msgpack-pure: Not Installed
  mysql-python: Not Installed
     pycparser: 2.20
      pycrypto: Not Installed
  pycryptodome: 3.6.1
        pygit2: 1.7.1
        Python: 3.8.10 (default, Nov 26 2021, 20:14:08)
  python-gnupg: 0.4.5
        PyYAML: 5.3.1
         PyZMQ: 18.1.1
         smmap: 2.0.5
       timelib: Not Installed
       Tornado: 4.5.3
           ZMQ: 4.3.2

System Versions:
          dist: ubuntu 20.04 focal
        locale: utf-8
       machine: x86_64
       release: 5.4.0-99-generic
        system: Linux
       version: Ubuntu 20.04 focal

[waynew]

Oh yeah, this is uh... interesting. The file.comment module was actually deprecated back in 0.17.0, but never removed. The file.comment state uses its own custom regex, while it then calls file.search (which uses file.replace) to know if it should change it or not. But then it uses the file.comment state, which uses a different set of behaviors.

It should probably just use file.replace - once with dry run for test, and once without to actually make the changes 🙃