[Bug]: queue=True no longer works without a minion

What happened?

When running salt-call --local state.highstate queue=True without any minion present, it used to be the case that concurrent salt-calls would queue among themselves.

However, since #68694 was implemented (3006.21), queue=True now silently assumes that a minion is running. If one is not, then any job that queues itself by writing to /var/cache/salt/minion/state_queue/ becomes a no-op as nothing will ever pick it up. Worse, the presence of this queue file will convince all subsequent queue=True jobs to immediately give up, write their own queue file, and exit. This effectively permanently disables salt as soon as two parallel jobs ever collide for the first time, assuming all jobs use queue=True.

Doing queue=<int> for some sensible upper bound seems to be a partial workaround as this restores the old in-process queuing behaviour, but this still hangs infinitely if any queue files already exist.

Ideally, queue=True should avoid delegating to a daemon that does not exist, and fall back to the old behaviour. Right now, this is a regression for minion-less setups.

Type of salt install

Official rpm

Major version

3006.x

What supported OS are you seeing the problem on? Can select multiple. (If bug appears on an unsupported OS, please open a GitHub Discussion instead)

rhel-8

salt --versions-report output

Salt Version:
          Salt: 3006.21
 
Python Version:
        Python: 3.10.19 (main, Feb  5 2026, 07:05:38) [GCC 11.2.0]
 
Dependency Versions:
          cffi: 2.0.0
      cherrypy: 18.10.0
  cryptography: 42.0.5
      dateutil: 2.8.1
     docker-py: Not Installed
         gitdb: Not Installed
     gitpython: Not Installed
        Jinja2: 3.1.6
       libgit2: Not Installed
  looseversion: 1.0.2
      M2Crypto: Not Installed
          Mako: Not Installed
       msgpack: 1.0.2
  msgpack-pure: Not Installed
  mysql-python: Not Installed
     packaging: 24.0
     pycparser: 2.21
      pycrypto: Not Installed
  pycryptodome: 3.19.1
        pygit2: Not Installed
  python-gnupg: 0.4.8
        PyYAML: 6.0.1
         PyZMQ: 23.2.0
        relenv: 0.22.3
         smmap: Not Installed
       timelib: 0.3.0
       Tornado: 4.5.3
           ZMQ: 4.3.4
 
System Versions:
          dist: ahv 10.3.1.9
        locale: utf-8
       machine: x86_64
       release: 6.6.106-10.3.1.9s1c2r5.el8.x86_64
        system: Linux
       version: Nutanix AHV 10.3.1.9

Reproduce the issue with parallel salt-call --local state.highstate queue=True commands and inspect the change from #68694, focusing on how queued jobs are handled when no minion is running. Confirm the behavior against existing queue handling, then verify that minion-less calls no longer become permanently blocked by queue files and that concurrent calls still queue correctly.