Fix a crash reading a Gmsh mesh with volume tags

meshmode/mesh/io.py

@@ -20,6 +20,8 @@
 THE SOFTWARE.
 """
 
+from typing import Tuple, Optional, List
+
 import numpy as np
 
 from gmsh_interop.reader import (  # noqa: F401
@@ -47,6 +49,8 @@
 # {{{ gmsh receiver
 
 class GmshMeshReceiver(GmshMeshReceiverBase):
+    tags: Optional[List[Tuple[int, int]]]
+
     def __init__(self, mesh_construction_kwargs=None):
         # Use data fields similar to meshpy.triangle.MeshInfo and
         # meshpy.tet.MeshInfo
@@ -82,6 +86,8 @@ def set_up_elements(self, count):
         self.element_nodes = [None] * count
         self.element_types = [None] * count
         self.element_markers = [None] * count
+        self.tags = []
+        self.gmsh_tag_index_to_mine = {}
 
     def add_element(self, element_nr, element_type, vertex_nrs,
             lexicographic_nodes, tag_numbers):
@@ -98,10 +104,6 @@ def finalize_elements(self):
 
     # May raise ValueError if try to add different tags with the same name
     def add_tag(self, name, index, dimension):
-        if self.tags is None:
-            self.tags = []
-        if self.gmsh_tag_index_to_mine is None:
-            self.gmsh_tag_index_to_mine = {}
         # add tag if new
         if index not in self.gmsh_tag_index_to_mine:
             self.gmsh_tag_index_to_mine[index] = len(self.tags)

test/test_mesh.py

@@ -1481,6 +1481,27 @@ def separated(x, y):
 # }}}
 
 
+def test_gmsh_tag_reading():
+    from meshmode.mesh.io import generate_gmsh, ScriptSource
+    generate_gmsh(ScriptSource("""
+        h = 1;                     // Characteristic length of a mesh element
+        Point(1) = {0, 0, 0, h};   // Point construction
+        Point(2) = {10, 0, 0, h};
+        Point(3) = {10, 10, 0, h};
+        Point(4) = {0, 10, 0, h};
+        Line(1) = {1,2};            //Lines
+        Line(2) = {2,3};
+        Line(3) = {3,4};
+        Line(4) = {4,1};
+        Curve Loop(1) = {1,2,3,4};   // A Boundary
+        Plane Surface(1) = {1};     // A Surface
+        Physical Surface(1) = {1};  // Setting a label to the Surface
+
+        Mesh 2;
+        RecombineMesh;
+        """, ".geo"), dimensions=2)
+
+
 if __name__ == "__main__":
     import sys
     if len(sys.argv) > 1: