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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Unexpected change in behavior in plt.subplot","articleBody":"\u003c!--To help us understand and resolve your issue, please fill out the form to the best of your ability.--\u003e\r\n\u003c!--You can feel free to delete the sections that do not apply.--\u003e\r\n\r\n### Bug report\r\n\r\n**Bug summary**\r\n\r\n#19153 introduced some changes that had (I think) unintended consequences when passing custom kwargs to projections\r\n\r\n**Code for reproduction**\r\n\r\nPrior to #19153, the following code returned ``False``, that is, two different axes were created:\r\n\r\n```python\r\nfrom astropy.wcs import WCS\r\nimport matplotlib.pyplot as plt\r\n\r\nwcs1 = WCS(naxis=3)\r\nwcs1.wcs.ctype = ['x', 'y', 'z']\r\n\r\nax1 = plt.subplot(1, 1, 1, projection=wcs1, slices=('x', 'y', 1))\r\n\r\nwcs2 = WCS(naxis=3)\r\nwcs2.wcs.ctype = ['a', 'b', 'c']\r\n\r\nax2 = plt.subplot(1, 1, 1, projection=wcs2, slices=('x', 2, 'y'))\r\n\r\nprint(ax1 is ax2)\r\n```\r\n\r\nNo deprecation warning or future warning was raised in this case.\r\n\r\nFollowing #19153, this silently ignores the projection and slices in the second call and the print statement returns ``True``.\r\n\r\nI don't think #19153 was intended to start making ``plt.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\r\n\r\n**Actual outcome**\r\n\r\n``ax1`` and ``ax2`` are the same\r\n\r\n**Expected outcome**\r\n\r\n``ax1`` and ``ax2`` should be different","author":{"url":"https://github.com/astrofrog","@type":"Person","name":"astrofrog"},"datePublished":"2021-02-02T13:06:13.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":27},"url":"https://github.com/19432/matplotlib/issues/19432"}