From 015280a8320e1ce80792b9bd6346a2105c2efd95 Mon Sep 17 00:00:00 2001
From: Alexander Kornienko <alexfh@google.com>
Date: Wed, 4 Dec 2013 12:21:08 +0000
Subject: [PATCH] Leave constructor initializer lists on one line in styles
 with no column limit.

Summary:
Allow tryFitMultipleLinesInOne join unwrapped lines when
ContinuationIndenter::mustBreak doesn't agree. But don't merge any lines, that
are separate in the input.

Reviewers: djasper

Reviewed By: djasper

CC: cfe-commits, klimek

Differential Revision: http://llvm-reviews.chandlerc.com/D2321

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@196378 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Format/Format.cpp           | 22 +++++++++++++-----
 unittests/Format/FormatTest.cpp | 40 ++++++++++++++++++++++++++++-----
 2 files changed, 50 insertions(+), 12 deletions(-)

diff --git a/lib/Format/Format.cpp b/lib/Format/Format.cpp
index ee9fe7625d..156ff6429c 100644
--- a/lib/Format/Format.cpp
+++ b/lib/Format/Format.cpp
@@ -439,12 +439,13 @@ public:
 
   /// \brief Formats the line starting at \p State, simply keeping all of the
   /// input's line breaking decisions.
-  void format(unsigned FirstIndent, const AnnotatedLine *Line) {
+  void format(unsigned FirstIndent, const AnnotatedLine *Line,
+              bool LineIsMerged) {
     LineState State =
         Indenter->getInitialState(FirstIndent, Line, /*DryRun=*/false);
     while (State.NextToken != NULL) {
       bool Newline =
-          Indenter->mustBreak(State) ||
+          (!LineIsMerged && Indenter->mustBreak(State)) ||
           (Indenter->canBreak(State) && State.NextToken->NewlinesBefore > 0);
       Indenter->addTokenToState(State, Newline, /*DryRun=*/false);
     }
@@ -468,9 +469,6 @@ public:
     if (TheLine->Last->Type == TT_LineComment)
       return 0;
 
-    if (Indent > Style.ColumnLimit)
-      return 0;
-
     unsigned Limit =
         Style.ColumnLimit == 0 ? UINT_MAX : Style.ColumnLimit - Indent;
     // If we already exceed the column limit, we set 'Limit' to 0. The different
@@ -479,6 +477,9 @@ public:
                 ? 0
                 : Limit - TheLine->Last->TotalLength;
 
+    if (Indent > Limit)
+      return 0;
+
     if (I + 1 == E || I[1]->Type == LT_Invalid)
       return 0;
 
@@ -658,6 +659,14 @@ public:
       if (static_cast<int>(Indent) + Offset >= 0)
         Indent += Offset;
       unsigned MergedLines = Joiner.tryFitMultipleLinesInOne(Indent, I, E);
+      if (MergedLines > 0 && Style.ColumnLimit == 0) {
+        // Disallow line merging if there is a break at the start of one of the
+        // input lines.
+        for (unsigned i = 0; i < MergedLines; ++i) {
+          if (I[i + 1]->First->NewlinesBefore > 0)
+            MergedLines = 0;
+        }
+      }
       if (!DryRun) {
         for (unsigned i = 0; i < MergedLines; ++i) {
           join(*I[i], *I[i + 1]);
@@ -702,7 +711,8 @@ public:
           // FIXME: Implement nested blocks for ColumnLimit = 0.
           NoColumnLimitFormatter Formatter(Indenter);
           if (!DryRun)
-            Formatter.format(Indent, &TheLine);
+            Formatter.format(Indent, &TheLine,
+                             /*LineIsMerged=*/MergedLines > 0);
         } else {
           Penalty += format(TheLine, Indent, DryRun);
         }
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 88b2a0b31a..f5a0bdd634 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -4891,6 +4891,28 @@ TEST_F(FormatTest, PullTrivialFunctionDefinitionsIntoSingleLine) {
 
   verifyFormat("void f() {}", getLLVMStyleWithColumns(11));
   verifyFormat("void f() {\n}", getLLVMStyleWithColumns(10));
+
+  FormatStyle NoColumnLimit = getLLVMStyle();
+  NoColumnLimit.ColumnLimit = 0;
+  EXPECT_EQ("A() : b(0) {}", format("A():b(0){}", NoColumnLimit));
+  EXPECT_EQ("class C {\n"
+            "  A() : b(0) {}\n"
+            "};", format("class C{A():b(0){}};", NoColumnLimit));
+  EXPECT_EQ("A()\n"
+            "    : b(0) {\n"
+            "}",
+            format("A()\n:b(0)\n{\n}", NoColumnLimit));
+
+  FormatStyle DoNotMergeNoColumnLimit = NoColumnLimit;
+  DoNotMergeNoColumnLimit.AllowShortFunctionsOnASingleLine = false;
+  EXPECT_EQ("A()\n"
+            "    : b(0) {\n"
+            "}",
+            format("A():b(0){}", DoNotMergeNoColumnLimit));
+  EXPECT_EQ("A()\n"
+            "    : b(0) {\n"
+            "}",
+            format("A()\n:b(0)\n{\n}", DoNotMergeNoColumnLimit));
 }
 
 TEST_F(FormatTest, UnderstandContextOfRecordTypeKeywords) {
@@ -7340,12 +7362,18 @@ TEST_F(FormatTest, FormatsWithWebKitStyle) {
 
   // Constructor initializers are formatted one per line with the "," on the
   // new line.
-  verifyFormat("Constructor()\n"
-               "    : aaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaa)\n"
-               "    , aaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaa, // break\n"
-               "                               aaaaaaaaaaaaaa)\n"
-               "    , aaaaaaaaaaaaaaaaaaaaaaa() {}",
-               Style);
+  EXPECT_EQ(
+      "Constructor()\n"
+      "    : aaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaa)\n"
+      "    , aaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaa, // break\n"
+      "                               aaaaaaaaaaaaaa)\n"
+      "    , aaaaaaaaaaaaaaaaaaaaaaa() {}",
+      format("Constructor()\n"
+             "    : aaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaa)\n"
+             "    , aaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaa, // break\n"
+             "                               aaaaaaaaaaaaaa)\n"
+             "    , aaaaaaaaaaaaaaaaaaaaaaa() {}",
+             Style));
 
   // Access specifiers should be aligned left.
   verifyFormat("class C {\n"
-- 
2.40.0