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Guard map path sampling against invalid dlon/dlat to prevent macOS pscoast crashes #9071

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Guard map path sampling against invalid dlon/dlat to prevent macOS pscoast crashes #9071

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6d78678
Initial plan
Copilot Jun 24, 2026
fab4621
Fix invalid map step handling in path sampling
Copilot Jun 24, 2026
9228a4f
Polish fallback path assignments for readability
Copilot Jun 24, 2026
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18 changes: 18 additions & 0 deletions src/gmt_map.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8011,6 +8011,15 @@ uint64_t gmtlib_lonpath (struct GMT_CTRL *GMT, double lon, double lat1, double l
/* Must do general case */
n = 0;
min_gap = 0.1 * GMT->current.setting.map_line_step;
if (!isfinite (GMT->current.map.dlat) || GMT->current.map.dlat <= 0.0) { /* Guard against invalid sampling step (e.g., antipodal singularities) */
gmt_M_malloc2 (GMT, tlon, tlat, 2U, NULL, double);
tlon[0] = tlon[1] = lon;
tlat[0] = lat1;
tlat[1] = lat2;
*x = tlon;
*y = tlat;
return (2ULL);
}
if ((n_alloc = lrint (ceil (fabs (lat2 - lat1) / GMT->current.map.dlat))) == 0) return (0);

n_alloc++; /* So n_alloc is at least 2 */
Expand Down Expand Up @@ -8108,6 +8117,15 @@ uint64_t gmtlib_latpath (struct GMT_CTRL *GMT, double lat, double lon1, double l
}
/* Here we try to walk along lat for small increment in longitude to make sure our steps are smaller than the line_step */
min_gap = 0.1 * GMT->current.setting.map_line_step;
if (!isfinite (GMT->current.map.dlon) || GMT->current.map.dlon <= 0.0) { /* Guard against invalid sampling step (e.g., antipodal singularities) */
gmt_M_malloc2 (GMT, tlon, tlat, 2U, NULL, double);
tlat[0] = tlat[1] = lat;
tlon[0] = lon1;
tlon[1] = lon2;
*x = tlon;
*y = tlat;
return (2ULL);
}
if ((n_alloc = lrint (ceil (fabs (lon2 - lon1) / GMT->current.map.dlon))) == 0) return (0); /* Initial guess to path length */

n_alloc++; /* n_alloc is at least 2 */
Expand Down