New error when two different ICs are specified

-Error thrown if an initial_condition parameter is provided along with an initial_from_file_var parameter for the same variable.

closes idaholab#20944

framework/src/actions/AddVariableAction.C

@@ -56,6 +56,7 @@ AddVariableAction::validParams()
                                      "Specifies a scaling factor to apply to this variable");
   params.addParam<std::vector<Real>>("initial_condition",
                                      "Specifies a constant initial condition for this variable");
+  params.addParam<std::string>("initial_from_file_var", "Initial from file");
   return params;
 }
 
@@ -132,6 +133,12 @@ AddVariableAction::init()
                "`scaling` parameter set, and they are different values. I don't know how you "
                "achieved this, but you need to rectify it.");
 
+  if (_pars.isParamSetByUser("initial_condition") &&
+      _pars.isParamSetByUser("initial_from_file_var"))
+    mooseError("Two initial conditions have been provided for the variable ",
+               name(),
+               ". One from the user and one from the restart input file.");
+
   _moose_object_pars.applySpecificParameters(_pars, {"order", "family", "scaling"});
 
   // Determine the MooseVariable type

test/tests/restart/scalar-var/part3.i

@@ -0,0 +1,50 @@
+[Mesh]
+  [fmg]
+    type = FileMeshGenerator
+    file = part1_out.e
+    use_for_exodus_restart = true
+  []
+[]
+
+[Variables]
+  [v]
+    family = MONOMIAL
+    order = CONSTANT
+    fv = true
+    initial_from_file_var = v
+    initial_condition = 0
+  []
+  [lambda]
+    family = SCALAR
+    order = FIRST
+    initial_from_file_var = lambda
+  []
+[]
+
+[FVKernels]
+  [advection]
+    type = FVElementalAdvection
+    variable = v
+    velocity = '1 0 0'
+  []
+  [lambda]
+    type = FVScalarLagrangeMultiplier
+    variable = v
+    lambda = lambda
+    phi0 = 1
+  []
+[]
+
+[Executioner]
+  type = Steady
+  petsc_options_iname = '-snes_max_it'
+  petsc_options_value = '0'
+  nl_abs_tol = 1e-10
+[]
+
+[Outputs]
+  [out]
+    type = Exodus
+    execute_on = 'final'
+  []
+[]

test/tests/restart/scalar-var/tests

@@ -16,5 +16,11 @@
       exodiff = part2_out.e
       detail = 'run restart input'
     []
+    [part3]
+      prereq = 'restarting/part1'
+      type = 'RunException'
+      input = part3.i
+      expect_err = 'Two initial conditions have been provided for the variable v. One from the user and one from the restart input file.'
+    []
   []
 []