clang-format: Several improvements around formatting braced lists.

In particular:
* If the difference between the longest and shortest element, we copped
  out of column format completely. Now, we instead allow to arrange
  these in a single column, essentially enforcing a one-per-line format.
* Allow column layout even if there are braced lists. Especially, if
  there are many short lists, this can be beneficial. The bad case,
  where there is a long nested init list is usually caught as we now
  limit the length difference of the longest and shortest element.

llvm-svn: 236851

1 files changed, 4 insertions, 3 deletions

diff --git a/clang/lib/Format/FormatToken.cpp b/clang/lib/Format/FormatToken.cpp
index 0addbfe..cc1ef55 100644
--- a/clang/lib/Format/FormatToken.cpp
+++ b/clang/lib/Format/FormatToken.cpp
@@ -199,13 +199,14 @@ void CommaSeparatedList::precomputeFormattingInfos(const FormatToken *Token) {
   // create a column layout. If it has a nested list, column layout ensures one
   // list element per line. If the difference between the shortest and longest
   // element is too large, column layout would create too much whitespace.
-  if (HasNestedBracedList || Commas.size() < 5 || Token->NestingLevel != 0 ||
-      MaxItemLength - MinItemLength > 10)
+  if (Commas.size() < 5 || Token->NestingLevel != 0)
     return;
 
   // We can never place more than ColumnLimit / 3 items in a row (because of the
   // spaces and the comma).
-  for (unsigned Columns = 1; Columns <= Style.ColumnLimit / 3; ++Columns) {
+  unsigned MaxColumns =
+      MaxItemLength - MinItemLength > 10 ? 1 : Style.ColumnLimit / 3;
+  for (unsigned Columns = 1; Columns <= MaxColumns; ++Columns) {
     ColumnFormat Format;
     Format.Columns = Columns;
     Format.ColumnSizes.resize(Columns);