[clang-format] Cannot disable array initializer bin packing

[JaredNeil]

Summary

Currently there is no way to disable bin-packing of long JavaScript or C++ array literals.
There are options for BinPackArguments and BinPackParameters, but no corresponding BinPackArrays option.
Instead, they automatically start bin-packing at 20 elements.
This seems like a strange decision and seems even more strange that there is no way to disable it.
I feel like this should either have it's own option, or should just always respect the BinPackArguments option, no matter how long the list.

Since the latter seems like an easier solution, I've just done that for now. If you think this would be better off with its own option, I'm happy to do that instead.

[MyDeveloperDay]

This review needs unit tests

[klimek]

IIRC this was done due to performance problems in large nested initializer lists. Can you verify this doesn't regress performance?

lib/Format/FormatToken.cpp

 }
 
 void CommaSeparatedList::precomputeFormattingInfos(const FormatToken *Token) {
   // FIXME: At some point we might want to do this for other lists, too.
   if (!Token->MatchingParen ||
       !Token->isOneOf(tok::l_brace, TT_ArrayInitializerLSquare))
     return;
 
-  // In C++11 braced list style, we should not format in columns unless they
-  // have many items (20 or more) or we allow bin-packing of function call
-  // arguments.
-  if (Style.Cpp11BracedListStyle && !Style.BinPackArguments &&
-      Commas.size() < 19)
+  // In C++11 braced list style, we should not format in columns unless  we
+  // allow bin-packing of function call arguments.
+  if (Style.Cpp11BracedListStyle && !Style.BinPackArguments)
     return;
 
-  // Limit column layout for JavaScript array initializers to 20 or more items
-  // for now to introduce it carefully. We can become more aggressive if this
-  // necessary.
-  if (Token->is(TT_ArrayInitializerLSquare) && Commas.size() < 19)
+  // The same applies to JavaScript array literals.
+  if (Token->is(TT_ArrayInitializerLSquare) && !Style.BinPackArguments)
     return;
 
   // Column format doesn't really make sense if we don't align after brackets.
   if (Style.AlignAfterOpenBracket == FormatStyle::BAS_DontAlign)
     return;
 
   FormatToken *ItemBegin = Token->Next;
   while (ItemBegin->isTrailingComment())