Shapefile reader: fix spurious warning when reading polygons (ammends…

… fix of OSGeo#8483, fixes OSGeo#8767)

autotest/ogr/data/shp/cb_2022_us_county_20m_extract.prj

@@ -0,0 +1 @@
+GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]

autotest/ogr/ogr_shape.py

@@ -1048,6 +1048,16 @@ def test_ogr_shape_read_multipolygon_as_invalid_polygon():
     )
 
 
+def test_ogr_shape_read_multipolygon_as_invalid_polygon_no_warning():
+
+    ds = ogr.Open("data/shp/cb_2022_us_county_20m_extract.shp")
+    lyr = ds.GetLayer(0)
+    gdal.ErrorReset()
+    with gdal.quiet_errors():
+        lyr.GetNextFeature()
+        assert gdal.GetLastErrorMsg() == ""
+
+
 ###############################################################################
 # Test alternate date formatting (#2746)
 

ogr/ogrsf_frmts/shape/shape2ogr.cpp

@@ -348,6 +348,7 @@ OGRGeometry *SHPReadOGRObject(SHPHandle hSHP, int iShape, SHPObject *psShape,
                     // Only inner rings
                     OGREnvelope sFirstEnvelope;
                     OGREnvelope sCurEnvelope;
+                    auto poExteriorRing = tabPolygons[0]->getExteriorRing();
                     tabPolygons[0]->getEnvelope(&sFirstEnvelope);
                     for (int iRing = 1; iRing < psShape->nParts; iRing++)
                     {
@@ -406,10 +407,10 @@ OGRGeometry *SHPReadOGRObject(SHPHandle hSHP, int iShape, SHPObject *psShape,
                                     topPoint = p;
                                 }
                             }
-                            if (!poRing->isPointInRing(&leftPoint) &&
-                                !poRing->isPointInRing(&rightPoint) &&
-                                !poRing->isPointInRing(&bottomPoint) &&
-                                !poRing->isPointInRing(&topPoint))
+                            if (!poExteriorRing->isPointInRing(&leftPoint) &&
+                                !poExteriorRing->isPointInRing(&rightPoint) &&
+                                !poExteriorRing->isPointInRing(&bottomPoint) &&
+                                !poExteriorRing->isPointInRing(&topPoint))
                             {
                                 bUseSlowMethod = true;
                                 break;