fix: resolve CI segfaults in contour plotting functions #402
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Replace unsafe merge() function usage in matplotlib wrapper with conditional calls to prevent memory access violations. The merge() function was causing segfaults when optional parameters were not present, particularly in colored_contours and ascii_heatmap_demo examples. Memory safety improvements: - Replace merge() with explicit conditional parameter forwarding - Fix both contour_filled() and add_contour_filled() functions - Prevent passing uninitialized zero-size arrays to underlying methods - Add comprehensive regression tests to prevent future occurrences Fixes critical CI blocking issue where examples crashed with SIGSEGV. 🤖 Generated with [Claude Code](https://claude.ai/code) Co-Authored-By: Claude <noreply@anthropic.com>
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krystophny
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Summary
Root Cause Analysis
The segfaults were caused by improper usage of the
merge()intrinsic function when forwarding optional parameters to underlying methods. When optional parameters were not present, merge() was still trying to pass zero-size allocated arrays, causing memory access violations.Technical Details
Fixed Functions:
contour_filled()in fortplot_matplotlib.f90 (line 112)add_contour_filled()in fortplot_matplotlib.f90 (line 437)Memory Safety Improvements:
merge(wp_levels, wp_levels, present(levels))with conditional parameter forwardingTesting
test_contour_memory_safety_regression.f90Impact
This fix unblocks all PR merges that were prevented by CI failures. The examples now complete successfully and produce expected output files.
🤖 Generated with Claude Code