Add methods to bypass ConditionalOperation when condition==nothing

src/AbstractOperations/conditional_operations.jl

@@ -151,6 +151,11 @@ end
     return ifelse(conditioned, value, co.mask)
 end
 
+# Fallbacks for reductions
+for reduction! in (:sum!, :maximum!, :minimum!, :all!, :any!, :prod!)
+    @eval Base.$(reduction!)(f, int_r, co::NoConditionCO, kwargs...) = Base.$(reduction!)(f, int_r, co.operand; kwargs...)
+end
+
 # Conditions: general, nothing, array
 @inline evaluate_condition(condition, i, j, k, grid, args...) = condition(i, j, k, grid, args...)
 @inline evaluate_condition(::Nothing, i, j, k, grid, args...) = true
@@ -202,6 +207,7 @@ end
 @inline conditional_length(c::ConditionalOperation, ::Colon) = conditional_length(c)
 @inline conditional_length(c::ConditionalOperation, ::NTuple{3}) = conditional_length(c)
 @inline conditional_length(c::ConditionalOperation, dims) = sum(conditional_one(c, 0); dims)
+@inline conditional_length(c::NoConditionCO, args...) = conditional_length(c.operand, args...)
 
 # Disambiguations
 @inline conditional_length(c::ConditionalOperation, dims::Int) = sum(conditional_one(c, 0); dims)

src/AbstractOperations/metric_field_reductions.jl

@@ -1,4 +1,4 @@
-using Statistics: mean!, sum!
+using Statistics: sum!
 
 using Oceananigans.Utils: tupleit
 using Oceananigans.Grids: regular_dimensions

test/test_field_scans.jl

@@ -2,7 +2,7 @@ include("dependencies_for_runtests.jl")
 
 using Statistics
 using Oceananigans.Architectures: on_architecture
-using Oceananigans.AbstractOperations: BinaryOperation
+using Oceananigans.AbstractOperations: BinaryOperation, GridMetricOperation
 using Oceananigans.Fields: ReducedField, CenterField, ZFaceField, compute_at!, @compute, reverse_cumsum!
 using Oceananigans.BoundaryConditions: fill_halo_regions!
 using Oceananigans.Grids: halo_size