Fix error with writing empty z/m shapefile

karimbahgat · karimbahgat · commit f2f91ce172fc · 2020-12-22T14:40:51.000+01:00
Also added tests to verify this for all shapetypes. Fixes #188
diff --git a/shapefile.py b/shapefile.py
@@ -1537,13 +1537,19 @@ def __shapefileHeader(self, fileObj, headerType='shp'):
         if self.shapeType in (11,13,15,18):
             # Z values are present in Z type
             zbox = self.zbox()
+            if zbox is None:
+                # means we have empty shapefile/only null geoms (see commentary on bbox above)
+                zbox = [0,0]
         else:
             # As per the ESRI shapefile spec, the zbox for non-Z type shapefiles are set to 0s
             zbox = [0,0]
         # Measure
         if self.shapeType in (11,13,15,18,21,23,25,28,31):
             # M values are present in M or Z type
             mbox = self.mbox()
+            if mbox is None:
+                # means we have empty shapefile/only null geoms (see commentary on bbox above)
+                mbox = [0,0]
         else:
             # As per the ESRI shapefile spec, the mbox for non-M type shapefiles are set to 0s
             mbox = [0,0]
diff --git a/test_shapefile.py b/test_shapefile.py
@@ -492,3 +492,17 @@ def test_write_geojson(tmpdir):
             assert json.dumps(feat.__geo_interface__)
         assert json.dumps(r.shapeRecords().__geo_interface__)
         assert json.dumps(r.__geo_interface__)
+
+shape_types = [k for k in shapefile.SHAPETYPE_LOOKUP.keys() if k != 31] # exclude multipatch
+
+@pytest.mark.parametrize("shape_type", shape_types)
+def test_write_empty_shapefile(tmpdir, shape_type):
+    """
+    Assert that can write an empty shapefile
+    """
+    filename = tmpdir.join("test").strpath
+    with shapefile.Writer(filename, shapeType=shape_type) as w:
+        w.field('field1', 'C') # required to create a valid dbf file
+
+    with shapefile.Reader(filename) as r:
+        assert r.shapeType == shape_type
