disallow zero layers, let's try this out

FluxML · Nov 4, 2024 · 288f8d5 · 288f8d5
1 parent ff73b44
commit 288f8d5
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Showing 2 changed files with 4 additions and 6 deletions.
diff --git a/src/layers/basic.jl b/src/layers/basic.jl
@@ -562,9 +562,10 @@ function Parallel(connection; kw...)
   if :layers in keys(layers) || :connection in keys(layers)
     throw(ArgumentError("a Parallel layer cannot have a named sub-layer called `connection` or `layers`"))
   end
-  isempty(layers) && return Parallel(connection, ())
   Parallel(connection, layers)
 end
+Parallel(connection, layers::Union{Tuple{}, @NamedTuple{}}) =
+    throw(ArgumentError("cannot construct a Parallel layer with no sub-layers"))
 
 @layer :expand Parallel
 

diff --git a/test/layers/basic.jl b/test/layers/basic.jl
@@ -266,11 +266,8 @@ using Flux: activations
       @test_throws ArgumentError Parallel(hcat, inv)()
       @test_throws ArgumentError Parallel(hcat, inv, sqrt)()
 
-      # zero layers -- not useful... can we make this an error without a breaking change?
-      @test Parallel(hcat) isa Parallel{typeof(hcat), Tuple{}}  # not a NamedTuple
-      @test Parallel(hcat)(1) == hcat()
-
-      @test Parallel(hcat, inv)(2) == hcat(1/2)  # still calls connection once.
+      # zero layers -- not useful... now made an error
+      @test_throws ArgumentError Parallel(hcat)
     end
 
     @testset "connection is called once" begin