From 54669342bead30987d16bd1646bd169a2c05fa0a Mon Sep 17 00:00:00 2001
From: Daniel Schwen <daniel.schwen@inl.gov>
Date: Tue, 29 Aug 2023 15:54:17 -0600
Subject: [PATCH] Enable initializer lists as defaults (#24455)

---
 framework/include/utils/InputParameters.h | 11 +++++++++++
 framework/src/actions/SetupMeshAction.C   | 16 ++++++++++------
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/framework/include/utils/InputParameters.h b/framework/include/utils/InputParameters.h
index 52e8765ad43e..acf25d312dd8 100644
--- a/framework/include/utils/InputParameters.h
+++ b/framework/include/utils/InputParameters.h
@@ -160,6 +160,17 @@ class InputParameters : public Parameters
   void addParam(const std::string & name, const std::string & doc_string);
   ///@}
 
+  /**
+   * Enable support for initializer lists as default arguments for container type.
+   */
+  template <typename T>
+  void addParam(const std::string & name,
+                const std::initializer_list<typename T::value_type> & value,
+                const std::string & doc_string)
+  {
+    addParam<T>(name, T{value}, doc_string);
+  }
+
   ///@{
   // BEGIN RANGE CHECKED PARAMETER METHODS
   /**
diff --git a/framework/src/actions/SetupMeshAction.C b/framework/src/actions/SetupMeshAction.C
index 28f72db61780..d54e72bdc15c 100644
--- a/framework/src/actions/SetupMeshAction.C
+++ b/framework/src/actions/SetupMeshAction.C
@@ -46,13 +46,15 @@ SetupMeshAction::validParams()
                         "mesh.  Note: This is NOT needed if you are reading "
                         "an actual first order mesh.");
 
-  params.addParam<std::vector<SubdomainID>>("block_id", "IDs of the block id/name pairs");
+  params.addParam<std::vector<SubdomainID>>("block_id", {}, "IDs of the block id/name pairs");
   params.addParam<std::vector<SubdomainName>>(
-      "block_name", "Names of the block id/name pairs (must correspond with \"block_id\"");
+      "block_name", {}, "Names of the block id/name pairs (must correspond with \"block_id\"");
 
-  params.addParam<std::vector<BoundaryID>>("boundary_id", "IDs of the boundary id/name pairs");
+  params.addParam<std::vector<BoundaryID>>("boundary_id", {}, "IDs of the boundary id/name pairs");
   params.addParam<std::vector<BoundaryName>>(
-      "boundary_name", "Names of the boundary id/name pairs (must correspond with \"boundary_id\"");
+      "boundary_name",
+      {},
+      "Names of the boundary id/name pairs (must correspond with \"boundary_id\"");
 
   params.addParam<bool>("construct_side_list_from_node_list",
                         false,
@@ -62,6 +64,7 @@ SetupMeshAction::validParams()
 
   params.addParam<std::vector<std::string>>(
       "displacements",
+      {},
       "The variables corresponding to the x y z displacements of the mesh.  If "
       "this is provided then the displacements will be taken into account during "
       "the computation. Creation of the displaced mesh can be suppressed even if "
@@ -72,9 +75,10 @@ SetupMeshAction::validParams()
       "Create the displaced mesh if the 'displacements' "
       "parameter is set. If this is 'false', a displaced mesh will not be created, "
       "regardless of whether 'displacements' is set.");
-  params.addParam<std::vector<BoundaryName>>("ghosted_boundaries",
-                                             "Boundaries to be ghosted if using Nemesis");
+  params.addParam<std::vector<BoundaryName>>(
+      "ghosted_boundaries", {}, "Boundaries to be ghosted if using Nemesis");
   params.addParam<std::vector<Real>>("ghosted_boundaries_inflation",
+                                     {},
                                      "If you are using ghosted boundaries you will want to set "
                                      "this value to a vector of amounts to inflate the bounding "
                                      "boxes by.  ie if you are running a 3D problem you might set "