Tweak list handling

2 files changed, 23 insertions, 21 deletions

diff --git a/src/rabbit_trunc_term.erl b/src/rabbit_trunc_term.erl
index 55eb30fa82..0340ae9121 100644
--- a/src/rabbit_trunc_term.erl
+++ b/src/rabbit_trunc_term.erl
@@ -55,17 +55,15 @@ shrink_term([A|B], N) when not is_list(B) ->
     shrink_term([A,B], N);
 shrink_term(T, N) when is_list(T) ->
     IsPrintable = io_lib:printable_list(T),
-    case length(T) > N of
-        true when IsPrintable ->
-            lists:append(lists:sublist(T, suffix_len(N-3)), "...");
-        true ->
-            lists:append([shrink_term(E, N-1) ||
-                             E <- lists:sublist(T, suffix_len(N-1))],
-                         ['...']);
-        false when IsPrintable ->
-            T;
-        false ->
-            [shrink_term(E, N-1) || E <- T]
+    Len = length(T),
+    case {Len > N, IsPrintable} of
+        {true, true}
+          when N > 3   -> lists:append(lists:sublist(T, resize(N-3)), "...");
+        {true, false}  -> lists:append([shrink_term(E, resize(N-1, Len)) ||
+                                          E <- lists:sublist(T, resize(N-1))],
+                                      ['...']);
+        {false, false} -> [shrink_term(E, resize(N-1, Len)) || E <- T];
+        _              -> T
     end;
 shrink_term(T, N) when is_tuple(T) ->
     case tuple_size(T) > N of
@@ -78,5 +76,7 @@ shrink_term(T, N) when is_tuple(T) ->
     end;
 shrink_term(T, _) -> T.
 
-suffix_len(N) -> erlang:max(N, 1).
+resize(N) -> resize(N, 1).
+
+resize(N, M) -> erlang:max(N, M).
 
diff --git a/src/rabbit_trunc_term_tests.erl b/src/rabbit_trunc_term_tests.erl
index e298da8171..697acc5d40 100644
--- a/src/rabbit_trunc_term_tests.erl
+++ b/src/rabbit_trunc_term_tests.erl
@@ -30,11 +30,13 @@ prop_trunc_any_term() ->
                     Shrunk  = rabbit_trunc_term:shrink_term(GenAny, MaxSz),
                     SzShrunk = erts_debug:size(Shrunk),
                     ?WHENFAIL(begin
-                                  io:format("MaxLen: ~p\n", [MaxSz]),
-                                  io:format("Input-Size: ~p\n", [SzInitial]),
-                                  io:format("Shrunk-Size: ~p\n", [SzShrunk]),
-                                  io:format("Input: ~p\n", [GenAny]),
-                                  io:format("Output: ~p\n", [Shrunk])
+                                  io:format("MaxLen: ~p~n", [MaxSz]),
+                                  io:format("SizeOfThing: ~p~n",
+                                            [size_of_thing(GenAny)]),
+                                  io:format("Input-Size: ~p~n", [SzInitial]),
+                                  io:format("Shrunk-Size: ~p~n", [SzShrunk]),
+                                  io:format("Input: ~p~n", [GenAny]),
+                                  io:format("Output: ~p~n", [Shrunk])
                               end,
                               case size_of_thing(GenAny) > MaxSz of
                                   true  -> true = SzShrunk < SzInitial;
@@ -42,16 +44,16 @@ prop_trunc_any_term() ->
                               end)
                 catch
                     _:Err ->
-                        io:format("\nException: ~p\n",
+                        io:format("\nException: ~p~n",
                                   [{Err, erlang:get_stacktrace()}]),
-                        io:format("Input: ~p\n", [GenAny]),
-                        io:format("Max-Size: ~p\n", [MaxSz]),
+                        io:format("Input: ~p~n", [GenAny]),
+                        io:format("Max-Size: ~p~n", [MaxSz]),
                         false
                 end
             end).
 
-size_of_thing(Thing) when is_binary(Thing)    -> size(Thing);
 size_of_thing(Thing) when is_bitstring(Thing) -> byte_size(Thing);
+size_of_thing(Thing) when is_binary(Thing)    -> size(Thing);
 size_of_thing(Thing) when is_list(Thing)      -> length(Thing);
 size_of_thing(Thing) when is_tuple(Thing)     -> size(Thing);
 size_of_thing(Thing)                          -> error({cannot_size, Thing}).