Change TVI0d constructor to conditionally promote

Promoting a large number of ITimes is expensive, so
this modifies the behavior to only do so if needed.

fixes

Author: imreddyTeja

ext/TimeVaryingInputs0DExt.jl

@@ -19,7 +19,7 @@ import ClimaUtilities.TimeVaryingInputs: extrapolation_bc
 
 import ClimaUtilities.TimeVaryingInputs
 
-import ClimaUtilities.TimeManager: ITime, date
+import ClimaUtilities.TimeManager: ITime, date, epoch
 using Dates
 
 """
@@ -105,12 +105,12 @@ function TimeVaryingInputs.TimeVaryingInput(
             "LinearPeriodFillingInterpolation is not supported when the input data is 1D",
         )
     end
-
+    if eltype(times) <: ITime && eltype(times) isa UnionAll
+        times = [promote(times...)...]
+    end
     if extrapolation_bc(method) isa PeriodicCalendar
         if extrapolation_bc(method) isa PeriodicCalendar{Nothing}
-            if !isequispaced(
-                eltype(times) <: ITime ? [float.(promote(times...))...] : times,
-            )
+            if !isequispaced(eltype(times) <: ITime ? float.(times) : times)
                 error(
                     "PeriodicCalendar() boundary condition cannot be used because data is defined at non uniform intervals of time",
                 )

test/time_varying_inputs.jl

@@ -76,6 +76,13 @@ end
         method = TimeVaryingInputs.LinearPeriodFillingInterpolation(),
     )
 
+    # test promote when some input times do not contain an epoch
+    promotion_tvi = TimeVaryingInputs.TimeVaryingInput(
+        [ITime(0; epoch = DateTime(2010)), ITime(1)],
+        ys,
+    )
+    @test all(t -> t.epoch == DateTime(2010), promotion_tvi.times)
+
     # Test PeriodicCalendar with non simple duration
     @test_throws ErrorException TimeVaryingInputs.PeriodicCalendar(
         Month(2),