r254933 - clang-format: Make wrapping after "./->" cheaper, even if the element

[Daniel Jasper via cfe-commits]

Author: djasper
Date: Mon Dec  7 13:50:48 2015
New Revision: 254933

URL: http://llvm.org/viewvc/llvm-project?rev=254933&view=rev
Log:
clang-format: Make wrapping after "./->" cheaper, even if the element
before it is not a closing parenthesis.

Otherwise, this frequently leads to "hanging" indents that users
perceive as "weird".

Before:
  return !soooooooooooooome_map.insert(
                                   aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)
              .second;

After:
  return !soooooooooooooome_map
              .insert(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)
              .second;

Modified:
    cfe/trunk/lib/Format/TokenAnnotator.cpp
    cfe/trunk/unittests/Format/FormatTest.cpp

Modified: cfe/trunk/lib/Format/TokenAnnotator.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Format/TokenAnnotator.cpp?rev=254933&r1=254932&r2=254933&view=diff
==============================================================================
--- cfe/trunk/lib/Format/TokenAnnotator.cpp (original)
+++ cfe/trunk/lib/Format/TokenAnnotator.cpp Mon Dec  7 13:50:48 2015
@@ -1743,10 +1743,20 @@ unsigned TokenAnnotator::splitPenalty(co
     return 2;
 
   if (Right.isMemberAccess()) {
-    if (Left.is(tok::r_paren) && Left.MatchingParen &&
-        Left.MatchingParen->ParameterCount > 0)
-      return 20; // Should be smaller than breaking at a nested comma.
-    return 150;
+    // Breaking before the "./->" of a chained call/member access is reasonably
+    // cheap, as formatting those with one call per line is generally
+    // desirable. In particular, it should be cheaper to break before the call
+    // than it is to break inside a call's parameters, which could lead to weird
+    // "hanging" indents. The exception is the very last "./->" to support this
+    // frequent pattern:
+    //
+    //   aaaaaaaa.aaaaaaaa.bbbbbbb().ccccccccccccccccccccc(
+    //       dddddddd);
+    //
+    // which might otherwise be blown up onto many lines. Here, clang-format
+    // won't produce "hanging" indents anyway as there is no other trailing
+    // call.
+    return Right.LastOperator ? 150 : 40;
   }
 
   if (Right.is(TT_TrailingAnnotation) &&

Modified: cfe/trunk/unittests/Format/FormatTest.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/unittests/Format/FormatTest.cpp?rev=254933&r1=254932&r2=254933&view=diff
==============================================================================
--- cfe/trunk/unittests/Format/FormatTest.cpp (original)
+++ cfe/trunk/unittests/Format/FormatTest.cpp Mon Dec  7 13:50:48 2015
@@ -3341,7 +3341,7 @@ TEST_F(FormatTest, LineBreakingInBinaryE
   verifyFormat("aaaaaa = aaaaaaa(aaaaaaa, // break\n"
                "                 aaaaaa) >>\n"
                "         bbbbbb;");
-  verifyFormat("Whitespaces.addUntouchableComment(\n"
+  verifyFormat("aa = Whitespaces.addUntouchableComment(\n"
                "    SourceMgr.getSpellingColumnNumber(\n"
                "        TheLine.Last->FormatTok.Tok.getLocation()) -\n"
                "    1);");
@@ -4157,10 +4157,14 @@ TEST_F(FormatTest, FormatsBuilderPattern
   verifyFormat("return aaaaaaaaaaaaaaaaa->aaaaa().aaaaaaaaaaaaa().aaaaaa() <\n"
                "       aaaaaaaaaaaaaaa->aaaaa().aaaaaaaaaaaaa().aaaaaa();");
   verifyFormat(
-      "aaaaaaa->aaaaaaa->aaaaaaaaaaaaaaaa(\n"
+      "aaaaaaa->aaaaaaa->aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(\n"
       "                    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)\n"
       "    ->aaaaaaaa(aaaaaaaaaaaaaaa);");
   verifyFormat(
+      "aaaaaaa->aaaaaaa\n"
+      "    ->aaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)\n"
+      "    ->aaaaaaaa(aaaaaaaaaaaaaaa);");
+  verifyFormat(
       "aaaaaaaaaaaaaaaaaaa()->aaaaaa(bbbbb)->aaaaaaaaaaaaaaaaaaa( // break\n"
       "    aaaaaaaaaaaaaa);");
   verifyFormat(
@@ -4224,6 +4228,12 @@ TEST_F(FormatTest, FormatsBuilderPattern
   // Prefer not to break after empty parentheses.
   verifyFormat("FirstToken->WhitespaceRange.getBegin().getLocWithOffset(\n"
                "    First->LastNewlineOffset);");
+
+  // Prefer not to create "hanging" indents.
+  verifyFormat(
+      "return !soooooooooooooome_map\n"
+      "            .insert(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)\n"
+      "            .second;");
 }
 
 TEST_F(FormatTest, BreaksAccordingToOperatorPrecedence) {
@@ -7373,8 +7383,8 @@ TEST_F(FormatTest, FormatObjCMethodExpr)
                "    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa];");
   verifyFormat("[aaaaaaaaaaaaaaaaaaaaaaa.aaaaaaaa[aaaaaaaaaaaaaaaaaaaaa]\n"
                "    aaaaaaaaaaaaaaaaaaaaaa];");
-  verifyFormat("[call aaaaaaaa.aaaaaa.aaaaaaaa.aaaaaaaa.aaaaaaaa.aaaaaaaa\n"
-               "        .aaaaaaaa];", // FIXME: Indentation seems off.
+  verifyFormat("[call aaaaaaaa.aaaaaa.aaaaaaaa.aaaaaaaa.aaaaaaaa\n"
+               "        .aaaaaaaa.aaaaaaaa];", // FIXME: Indentation seems off.
                getLLVMStyleWithColumns(60));
 
   verifyFormat(