René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: Regression on `tight_layout` when manually adding axes for colorbars","articleBody":"### Bug summary\n\nWhen creating manual floating axes to fill with colorbars, previous to version 3.5 a call to `fig.tight_layout()` on a figure with manually located axes would simply raise a warning that the figure contains axes incompatbile with tight layout. \r\n\r\nStarting in 3.5 we get the attribute error documented below. \n\n### Code for reproduction\n\n```python\nimport matplotlib\r\nimport matplotlib.pyplot as plt\r\nimport numpy as np\r\nmatplotlib.__version__\r\n# \u003e '3.5.0'\r\n\r\ndef add_cax(ax):\r\n    ax_rect = ax.get_position()\r\n    cax = fig.add_axes(\r\n        [ax_rect.x1 + 0.005, ax_rect.y0, 0.015, ax_rect.height]\r\n    )\r\n    return cax\r\n\r\nfig, axes = plt.subplots(1, 2)\r\npts = axes[1].scatter([0, 1], [0, 1], c=[1, 5])\r\ncax = add_cax(axes[1])\r\nfig.colorbar(pts, cax=cax) \r\nfig.tight_layout()\n```\n\n\n### Actual outcome\n\n---------------------------------------------------------------------------\r\nAttributeError                            Traceback (most recent call last)\r\n/var/folders/3c/nbn0xyrs4mldy84gltty_pt00000gn/T/ipykernel_87887/4094170185.py in \u003cmodule\u003e\r\n      3 cax = add_cax(axes[1])\r\n      4 fig.colorbar(pts, cax=cax, use_gridspec=True)\r\n----\u003e 5 fig.tight_layout()\r\n\r\n~/.venv/envs/rms-2.0.0/lib/python3.9/site-packages/matplotlib/figure.py in tight_layout(self, pad, h_pad, w_pad, rect)\r\n   3181         from .tight_layout import (\r\n   3182             get_subplotspec_list, get_tight_layout_figure)\r\n-\u003e 3183         subplotspec_list = get_subplotspec_list(self.axes)\r\n   3184         if None in subplotspec_list:\r\n   3185             _api.warn_external(\"This figure includes Axes that are not \"\r\n\r\n~/.venv/envs/rms-2.0.0/lib/python3.9/site-packages/matplotlib/tight_layout.py in get_subplotspec_list(axes_list, grid_spec)\r\n    232 \r\n    233         if hasattr(axes_or_locator, \"get_subplotspec\"):\r\n--\u003e 234             subplotspec = axes_or_locator.get_subplotspec()\r\n    235             subplotspec = subplotspec.get_topmost_subplotspec()\r\n    236             gs = subplotspec.get_gridspec()\r\n\r\n~/.venv/envs/rms-2.0.0/lib/python3.9/site-packages/matplotlib/colorbar.py in get_subplotspec(self)\r\n    281         ss = getattr(self._cbar.ax, 'get_subplotspec', None)\r\n    282         if ss is None:\r\n--\u003e 283             ss = self._orig_locator.get_subplotspec()\r\n    284         else:\r\n    285             ss = ss()\r\n\r\nAttributeError: 'NoneType' object has no attribute 'get_subplotspec'\n\n### Expected outcome\n\nExpect a warning about tight layout used with incompatible axes\n\n### Additional information\n\nFails under Matplotlib 3.5\r\n\r\nWorks (warns) under \u003c 3.4\n\n### Operating system\n\nMacOS, Windows, Ubuntu\n\n### Matplotlib Version\n\n3.5.0\n\n### Matplotlib Backend\n\n'module://matplotlib_inline.backend_inline'\n\n### Python version\n\n3.9.7\n\n### Jupyter version\n\n3.2.2\n\n### Installation\n\nconda","author":{"url":"https://github.com/ryandvmartin","@type":"Person","name":"ryandvmartin"},"datePublished":"2021-11-25T15:39:45.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/21749/matplotlib/issues/21749"}