Re-enable autoreset of colour in terminal

[MetRonnie]

Problem

The scheduler log would get a spurious color reset char (ESC[0m) at the start of the "DONE" line when not in no-detach mode.

This was being caused by autoreset=True being passed to

https://github.com/cylc/cylc-flow/blob/9abced91a08924bea02318839edb93a6fe2a5780/cylc/flow/terminal.py#L269-L270

and some weird interaction with the scheduler daemonization process. The "DONE" line in the log is the only line logged by scheduler_cli after the scheduler has finished running:

https://github.com/cylc/cylc-flow/blob/9abced91a08924bea02318839edb93a6fe2a5780/cylc/flow/scheduler_cli.py#L443-L445

Proposed Solution

[!NOTE] autoreset was set to False in:

• #6021 (cylc-flow 8.3.0)

Ideally we want autoreset to be set to True to ensure we don't permanently colour the terminal output by mistake. This will take some figuring out to achieve without getting the spurious reset character again.

I expect with more careful file handing around the daemonization it wouldn't happen (it shouldn't logically), e.g. close logs in the original process and re-open them in the fork?

https://github.com/cylc/cylc-flow/pull/6021#discussion_r1542620945

[oliver-sanders]

Just encountered this error (8.3.3), likely related:

Traceback (most recent call last):                                          
  File "/cylc/lib/python3.9/logging/__init__.py", line 1083, in emit        
    msg = self.format(record)                                               
  File "/cylc/lib/python3.9/logging/__init__.py", line 927, in format                         
    return fmt.format(record)                                               
  File "/cylc/lib/python3.9/site-packages/cylc/flow/loggingutil.py", line 102, in format                         
    text = cparse(self.COLORS[record.levelname].format(text))               
  File "/cylc/lib/python3.9/site-packages/ansimarkup/markup.py", line 54, in parse                         
    text = self.re_tag.sub(lambda m: self.sub_tag(m, tags, results), text)    
  File "/cylc/lib/python3.9/site-packages/ansimarkup/markup.py", line 54, in <lambda>                         
    text = self.re_tag.sub(lambda m: self.sub_tag(m, tags, results), text)    
  File "/cylc/lib/python3.9/site-packages/ansimarkup/markup.py", line 146, in sub_tag
    raise UnbalancedTag('closing tag "%s" violates nesting rules.' % markup)    
ansimarkup.markup.UnbalancedTag: closing tag "</fg #888888>" violates nesting rules.     

[oliver-sanders]

A recent change to the scheduler_cli code (https://github.com/cylc/cylc-flow/pull/6310) should make this easier than it was before as the detatch bit is no longer inline with the rest of the code which I think may have been the issue that triggered the change away from autoreset.