Fix a bug with how the remaining free space is calculated

src/lager_format.erl

@@ -145,7 +145,7 @@ build([], Acc, MaxLen, _O) ->
 
 build2([{C,As,F,Ad,P,Pad,Enc}|Cs], Count, MaxLen) ->
     {S, Len} = control2(C, As, F, Ad, P, Pad, Enc, MaxLen div Count),
-    [S|build2(Cs, Count - 1, MaxLen - abs(Len))];
+    [S|build2(Cs, Count - 1, MaxLen - Len)];
 build2([C|Cs], Count, MaxLen) ->
     [C|build2(Cs, Count, MaxLen)];
 build2([], _, _) -> [].
@@ -221,27 +221,27 @@ control(C, A, F, Adj, P, Pad, Enc, L) ->
 control2($w, [A], F, Adj, P, Pad, _Enc, L) ->
     Term = lager_trunc_io:fprint(A, L, [{lists_as_strings, false}]),
     Res = term(Term, F, Adj, P, Pad),
-    {Res, L - lists:flatlength(Res)};
+    {Res, lists:flatlength(Res)};
 control2($p, [A], F, Adj, P, Pad, _Enc, L) ->
     Term = lager_trunc_io:fprint(A, L, [{lists_as_strings, true}]),
     Res = term(Term, F, Adj, P, Pad),
-    {Res, L - lists:flatlength(Res)};
+    {Res, lists:flatlength(Res)};
 control2($W, [A,Depth], F, Adj, P, Pad, _Enc, L) when is_integer(Depth) ->
     Term = lager_trunc_io:fprint(A, L, [{depth, Depth}, {lists_as_strings, false}]),
     Res = term(Term, F, Adj, P, Pad),
-    {Res, L - lists:flatlength(Res)};
+    {Res, lists:flatlength(Res)};
 control2($P, [A,Depth], F, Adj, P, Pad, _Enc, L) when is_integer(Depth) ->
     Term = lager_trunc_io:fprint(A, L, [{depth, Depth}, {lists_as_strings, true}]),
     Res = term(Term, F, Adj, P, Pad),
-    {Res, L - lists:flatlength(Res)};
+    {Res, lists:flatlength(Res)};
 control2($s, [L0], F, Adj, P, Pad, latin1, L) ->
     List = lager_trunc_io:fprint(maybe_flatten(L0), L, [{force_strings, true}]),
     Res = string(List, F, Adj, P, Pad),
-    {Res, L - lists:flatlength(Res)};
+    {Res, lists:flatlength(Res)};
 control2($s, [L0], F, Adj, P, Pad, unicode, L) ->
     List = lager_trunc_io:fprint(unicode:characters_to_list(L0), L, [{force_strings, true}]),
     Res = uniconv(string(List, F, Adj, P, Pad)),
-    {Res, L - lists:flatlength(Res)}.
+    {Res, lists:flatlength(Res)}.
 
 maybe_flatten(X) when is_list(X) ->
     lists:flatten(X);