Default format of dimensionless Unit: undocumented change in 0.24

[khaeru]

Consider the following:

import pint

q = pint.Quantity(1.0, "")
print(f"{q.units}")

With pint 0.23:

• The output is 'dimensionless'.
• With instead f"{q.units:D}", the output is 'dimensionless'.
• With instead f"{q.units:~}", the output is ''.

With pint 0.24:

• The output is ''.
• It seems none of the format specifiers described on the String formatting specifications can be used to get 'dimensionless' as output.

This change is not mentioned in the change log, and there was not a PendingDeprecationWarning or FutureWarning to indicate this behaviour would change with 0.24.

[andrewgsavage]

@hgrecco would it be worth releasing a 0.24.1 formats dimensionless as dimensionless for these format specs?

[hgrecco]

Yes! And also to address #2009