Fix error handling in STRtree (#432)

* Fix error handling in STRtree

* Formatting

* Update CHANGELOG.rst

Co-authored-by: Joris Van den Bossche <jorisvandenbossche@gmail.com>

Co-authored-by: Joris Van den Bossche <jorisvandenbossche@gmail.com>

CHANGELOG.rst

@@ -27,7 +27,9 @@ Version 0.12 (unreleased)
 
 **Bug fixes**
 
-* ...
+* Raise ``GEOSException`` in the rare case when predicate evalution in ``STRtree.query``
+  errors. Previously, the exceptions were ignored silently and the geometry was added 
+  to the result (as if the predicate returned ``True``) (#432).
 
 
 **Acknowledgments**

pygeos/tests/test_strtree.py

@@ -211,6 +211,11 @@ def test_query_unsupported_predicate(tree):
         tree.query(pygeos.points(1, 1), predicate="disjoint")
 
 
+def test_query_predicate_errors(tree):
+    with pytest.raises(pygeos.GEOSException):
+        tree.query(pygeos.linestrings([1, 1], [1, float("nan")]), predicate="touches")
+
+
 def test_query_tree_with_none():
     # valid GEOS binary predicate, but not supported for query
     tree = pygeos.STRtree(

src/strtree.c

@@ -276,6 +276,7 @@ static char evaluate_predicate(void* context, FuncGEOS_YpY_b* predicate_func,
   GEOSGeometry* target_geom;
   const GEOSPreparedGeometry* prepared_geom_tmp;
   npy_intp i, size;
+  char predicate_result;
 
   if (prepared_geom == NULL) {
     // geom was not previously prepared, prepare it now
@@ -302,7 +303,10 @@ static char evaluate_predicate(void* context, FuncGEOS_YpY_b* predicate_func,
     get_geom(pg_geom, &target_geom);
 
     // keep the geometry if it passes the predicate
-    if (predicate_func(context, prepared_geom_tmp, target_geom)) {
+    predicate_result = predicate_func(context, prepared_geom_tmp, target_geom);
+    if (predicate_result == 2) {
+      return PGERR_GEOS_EXCEPTION;
+    } else if (predicate_result == 1) {
       kv_push(GeometryObject**, *out_geoms, pg_geom_loc);
       (*count)++;
     }