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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Support for pyproj: cpython.pythread APIs cause runtime crash","articleBody":"# Summary\n\npyproj builds successfully on GraalPy but crashes at runtime with `SystemError: internal exception occurred` due to unsupported `cpython.pythread` Cython APIs.\n\n# Environment\n\n- GraalPy 25.0.0 (Python 3.12.8), macOS ARM64\n- pyproj 3.7.2, PROJ 9.7.1\n\n# Reproduction\n\n```bash\ngraalpy -m venv .venv \u0026\u0026 source .venv/bin/activate\nPROJ_DIR=/path/to/proj pip install pyproj\npython -c \"from pyproj import CRS\"  # crashes\nError\n\nFile \"pyproj/_crs.pyx\", line 22, in init pyproj._crs\nSystemError: internal exception occurred\n```\n\n# Root Cause\npyproj's _context.pyx uses CPython thread-local storage APIs:\n\nfrom cpython.pythread cimport PyThread_tss_create, PyThread_tss_get, PyThread_tss_set\nThese are used unconditionally (no fallback for non-CPython implementations).\n\n# What I Tried\nPatched _compat.pyx to remove cpython cimport array,  this worked\nBut _context.pyx still crashes due to the cpython.pythread imports above\n\n# Suggested Fix\nEither:\n\n- GraalPy patches for pyproj (similar to numpy/pandas patches)\n- Implement cpython.pythread APIs: PyThread_tss_create, PyThread_tss_get, PyThread_tss_set\n\n# Impact\npyproj is required by geopandas and the broader geospatial Python ecosystem.","author":{"url":"https://github.com/shrynx","@type":"Person","name":"shrynx"},"datePublished":"2026-01-13T20:33:56.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/590/graalpython/issues/590"}