Bug report

Bug summary

#19153 introduced some changes that had (I think) unintended consequences when passing custom kwargs to projections

Code for reproduction

Prior to#19153, the following code returnedFalse, that is, two different axes were created:

fromastropy.wcsimportWCSimportmatplotlib.pyplotaspltwcs1=WCS(naxis=3)wcs1.wcs.ctype= ['x','y','z']ax1=plt.subplot(1,1,1,projection=wcs1,slices=('x','y',1))wcs2=WCS(naxis=3)wcs2.wcs.ctype= ['a','b','c']ax2=plt.subplot(1,1,1,projection=wcs2,slices=('x',2,'y'))print(ax1isax2)

No deprecation warning or future warning was raised in this case.

Following#19153, this silently ignores the projection and slices in the second call and the print statement returnsTrue.

I don't think#19153 was intended to start makingplt.subplot return the same axes in some cases, rather I thought the goal of that PR was to remove re-use of axes in certain circumstances, so I think this is a regression/bug

Actual outcome

ax1 andax2 are the same

Expected outcome

ax1 andax2 should be different