Fix %%python display() routing to wrong kernel#371
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blink1073 merged 3 commits intoCalysto:mainfrom Mar 13, 2026
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MetaKernel.meta_kernel was only set once at first-kernel creation, so display() calls inside %%python silently routed to a stale kernel instance instead of the currently-executing one. Fix by updating meta_kernel in PythonMagic.eval() before each evaluation. Adds capture_send_messages() test helper and test_python_magic_html_display covering returning HTML objects, explicit display() calls, and display() calls inside user-defined functions.
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## main #371 +/- ##
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Coverage 90.99% 90.99%
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After %%python runs on a kernel, the globally monkey-patched IPython.display.display must route output to that kernel (the parent), not to a stale instance from a previous %%python call on a different kernel.
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Closes #187.
Summary
MetaKernel.meta_kernelwas only assigned once — when the very first kernel instance was created. Any subsequentdisplay()call inside a%%pythoncell silently routed to that stale kernel instance rather than the currently-executing one, causing rich display output (HTML,Markdown, etc.) to be dropped.MetaKernel.meta_kernel = self.kernelat the top ofPythonMagic.eval()sodisplay()always routes to the active kernel.Test plan
capture_send_messages()context manager totests/utils.pyfor interceptingsend_responsecalls in tests.test_python_magic_html_displaycovering:HTML(...)as the last expression in%%python→execute_resultwithtext/htmldisplay(HTML(...))explicit call →display_datawithtext/htmldisplay(HTML(...))internally →display_datawithtext/html(the pattern from the issue)