bpo-46752: Uniform TaskGroup.__repr__

[asvetlov]

Other asyncio objects use prop=val format, not prop:val.

https://bugs.python.org/issue46752

[gvanrossum]

Didn't you say other asyncio objects use prop=val? Were you going to add that? (I guess it'll require updating a few tests.)

[gvanrossum]

Suggested change

	info_str = ' ' + ' '.join(info)
	return f'<TaskGroup{info_str}>'
	info_str = ' '.join(info)
	return f'<TaskGroup {info_str}>'

[asvetlov]

After applying the suggestion, a repr for created TaskGroup before __enter__() is called will be "<TaskGroup >" (note the space after class name).
Is it ok? Should we care about this rare case?

[1st1]

IMO accumulating strings in [] isn't a great pattern unless you have to use it for performance reasons. /my2c.

[gvanrossum]

After applying the suggestion, a repr for created TaskGroup before __enter__() is called will be "<TaskGroup >" (note the space after class name). Is it ok? Should we care about this rare case?

The original code has the same issue AFAICT. If you don't want that you could initialize info = [''] perhaps?

[gvanrossum]

IMO accumulating strings in [] isn't a great pattern unless you have to use it for performance reasons. /my2c.

Meh. IIRC the info pattern is used all over asyncio (e.g. _task_repr_info in base_tasks.py).

[asvetlov]

info = [''] is clever, applied.

Yes, info list is used by other asyncio repr's. I'd like to have the similar approach across the library.

[asvetlov]

Oops, I've mentioned the problem ': vs =' problem but didn't actually resolve it.
Fixed. I'm sorry. Now = is used.

[asvetlov]

@gvanrossum do you want tests for __repr__?
I'm lazy but can write them on demand.

[gvanrossum]

No need for tests. Maybe a new contributor will add them. :-)