fix and closes idaholab#15793

framework/src/meshgenerators/BreakMeshByBlockGenerator.C

@@ -12,7 +12,7 @@
 
 #include "libmesh/distributed_mesh.h"
 #include "libmesh/elem.h"
-
+#include "libmesh/partitioner.h"
 #include <typeinfo>
 
 registerMooseObject("MooseApp", BreakMeshByBlockGenerator);
@@ -163,6 +163,7 @@ BreakMeshByBlockGenerator::generate()
   }     // end nodeptr check
 
   addInterfaceBoundary(*mesh);
+  Partitioner::set_node_processor_ids(*mesh);
   return dynamic_pointer_cast<MeshBase>(mesh);
 }
 

test/tests/meshgenerators/break_mesh_by_block_generator/hanging_nodes_parallel.i

@@ -0,0 +1,69 @@
+[GlobalParams]
+  displacements = "disp_x disp_y disp_z"
+[]
+
+[Mesh]
+  [./msh]
+    type = GeneratedMeshGenerator
+    nx = 2
+    ny = 3
+    nz = 4
+    xmin = -2.5
+    xmax = 2.5
+    ymin = -2
+    ymax = 2
+    zmin = -1.5
+    zmax = 1.5
+    dim = 3
+  [../]
+  [./subdomain_1]
+    type = SubdomainBoundingBoxGenerator
+    input = msh
+    bottom_left = '-2.5 -2 -1'
+    top_right = '2.5 0 0.5'
+    block_id = 1
+  []
+  [./subdomain_2]
+    type = SubdomainBoundingBoxGenerator
+    input = subdomain_1
+    bottom_left = '-2.5 0 -1'
+    top_right = '2.5 2 0.5'
+    block_id = 2
+  []
+  [./subdomain_3]
+    type = SubdomainBoundingBoxGenerator
+    input = subdomain_2
+    bottom_left = '-2.5 -2 0.5'
+    top_right = '1.25 2 1.5'
+    block_id = 3
+  []
+  [./subdomain_4]
+    type = SubdomainBoundingBoxGenerator
+    input = subdomain_3
+    bottom_left = '1.25 -2 0.5'
+    top_right = '5 2 1.5'
+    block_id = 4
+  []
+  [./subdomain_5]
+    type = SubdomainBoundingBoxGenerator
+    input = subdomain_4
+    bottom_left = '-2.5 -2 -1.5'
+    top_right = '1.25 2 -1'
+    block_id = 3
+  []
+  [./subdomain_6]
+    type = SubdomainBoundingBoxGenerator
+    input = subdomain_5
+    bottom_left = '1.25 -2 -1.5'
+    top_right = '2.5 2 -1'
+    block_id = 4
+  []
+  [./split]
+    type = BreakMeshByBlockGenerator
+    input = subdomain_6
+  []
+[]
+
+[Outputs]
+  exodus = true
+[]

test/tests/meshgenerators/break_mesh_by_block_generator/tests

@@ -70,4 +70,18 @@
     mesh_mode = 'REPLICATED'
     recover = false
   [../]
+
+  [./hanging_nodes]
+    type = 'Exodiff'
+    input = 'hanging_nodes_parallel.i'
+    cli_args = '--mesh-only'
+    exodiff = 'hanging_nodes_parallel_in.e'
+    requirement = 'MOOSE shall be able to create separate blocks in a mesh in parallel'
+    design = 'meshgenerators/BreakMeshByBlockGenerator.md'
+    issues = '#15793'
+    mesh_mode = 'REPLICATED'
+    min_parallel = 4
+    max_parallel = 5
+    recover = false
+  [../]
 []