prevents metadata to be repeated in the DSL

Author: TorkelE

src/reaction_network.jl

@@ -655,6 +655,12 @@ function push_reactions!(reactions::Vector{ReactionStruct}, sub_line::ExprValues
             push!(metadata_i.args, :(only_use_rate = $(in(arrow, pure_rate_arrows))))
         end
 
+        # Checks that metadata fields are unqiue.
+        metadata_entries = [arg.args[1] for arg in metadata_i.args]
+        if length(unique(metadata_entries)) < length(metadata_entries)
+            error("Some reaction metadata fields where repeated: $(metadata_entries)")
+        end
+
         push!(reactions, ReactionStruct(get_tup_arg(sub_line, i), get_tup_arg(prod_line, i),
                                         get_tup_arg(rate, i), metadata_i))
     end

test/dsl/dsl_basics.jl

@@ -190,6 +190,14 @@ let
     @test isequal(get_metadata_dict(rx3), get_metadata_dict(rxs[3]))
 end
 
+# Checks that repeated metadata throws errors.
+let 
+    @test_throws LoadError @eval @reaction k, 0 --> X, [md1=1.0, md1=2.0] 
+    @test_throws LoadError @eval @reaction_network begin
+        k, 0 --> X, [md1=1.0, md1=1.0] 
+    end 
+end
+
 # Tests for nested metadata.
 let
     rn1 = @reaction_network reactions begin