Index: lib/Format/ContinuationIndenter.cpp
===================================================================
--- lib/Format/ContinuationIndenter.cpp
+++ lib/Format/ContinuationIndenter.cpp
@@ -211,6 +211,7 @@
 bool ContinuationIndenter::canBreak(const LineState &State) {
   const FormatToken &Current = *State.NextToken;
   const FormatToken &Previous = *Current.Previous;
+
   assert(&Previous == Current.Previous);
   if (!Current.CanBreakBefore && !(State.Stack.back().BreakBeforeClosingBrace &&
                                    Current.closesBlockOrBlockTypeList(Style)))
Index: lib/Format/TokenAnnotator.cpp
===================================================================
--- lib/Format/TokenAnnotator.cpp
+++ lib/Format/TokenAnnotator.cpp
@@ -2968,6 +2968,9 @@
       return false;
     return true;
   }
+  if (Right.is(tok::r_square) && Right.MatchingParen &&
+      Right.MatchingParen->is(TT_ProtoExtensionLSquare))
+    return false;
   if (Right.is(TT_SelectorName) || (Right.is(tok::identifier) && Right.Next &&
                                     Right.Next->is(TT_ObjCMethodExpr)))
     return Left.isNot(tok::period); // FIXME: Properly parse ObjC calls.
@@ -3060,6 +3063,7 @@
   if ((Left.is(TT_AttributeSquare) && Right.is(tok::l_square)) ||
       (Left.is(tok::r_square) && Right.is(TT_AttributeSquare)))
     return false;
+
   return Left.isOneOf(tok::comma, tok::coloncolon, tok::semi, tok::l_brace,
                       tok::kw_class, tok::kw_struct, tok::comment) ||
          Right.isMemberAccess() ||
Index: unittests/Format/FormatTestTextProto.cpp
===================================================================
--- unittests/Format/FormatTestTextProto.cpp
+++ unittests/Format/FormatTestTextProto.cpp
@@ -392,10 +392,12 @@
                "     .long/longg.longlong] { key: value }");
   verifyFormat("[aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/\n"
                " bbbbbbbbbbbbbb] { key: value }");
-  verifyFormat("[aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
-               "] { key: value }");
-  verifyFormat("[aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
-               "] {\n"
+  // These go over the column limit intentionally, since the alternative
+  // [aa..a\n] is worse.
+  verifyFormat("[aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa] {\n"
+               "  key: value\n"
+               "}");
+  verifyFormat("[aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa] {\n"
                "  [type.type] {\n"
                "    keyyyyyyyyyyyyyy: valuuuuuuuuuuuuuuuuuuuuuuuuue\n"
                "  }\n"
@@ -475,5 +477,20 @@
                "     \"str2\"\n");
 }
 
+TEST_F(FormatTestTextProto, PutsMultipleEntriesInExtensionsOnNewlines) {
+  FormatStyle Style = getGoogleStyle(FormatStyle::LK_TextProto);
+  verifyFormat("pppppppppp: {\n"
+               "  ssssss: \"http://example.com/blahblahblah\"\n"
+               "  ppppppp: \"sssss/MMMMMMMMMMMM\"\n"
+               "  [ns.sssss.eeeeeeeee.eeeeeeeeeeeeeee] { begin: 24 end: 252 }\n"
+               "  [ns.sssss.eeeeeeeee.eeeeeeeeeeeeeee] {\n"
+               "    begin: 24\n"
+               "    end: 252\n"
+               "    key: value\n"
+               "    key: value\n"
+               "  }\n"
+               "}", Style);
+}
+
 } // end namespace tooling
 } // end namespace clang