[clang-format] Revert a feature in RemoveBracesLLVM

[owenpan]

Summary

Revert the handling of a single-statement block that gets wrapped.

See https://github.com/llvm/llvm-project/issues/53543.

[curdeius]

Ok, so now (until a new fix), it will always remove the braces for a single statement even if it's multi-line. That's fine.

[owenpan]

In D118873#3292956, @curdeius wrote:

Ok, so now (until a new fix), it will always remove the braces for a single statement even if it's multi-line. That's fine.

Yep.

clang/lib/Format/UnwrappedLineParser.h

enum class IfStmtKind {
     IfOnly,  // An if statement without the else clause.
     IfElse,  // An if statement followed by else but not else if.
     IfElseIf // An if statement followed by else if.
   };
 
   void reset();
   void parseFile();
   bool precededByCommentOrPPDirective() const;
-  bool mightFitOnOneLine() const;
   bool parseLevel(bool HasOpeningBrace, IfStmtKind *IfKind = nullptr);
   IfStmtKind parseBlock(bool MustBeDeclaration = false, unsigned AddLevels = 1u,
                         bool MunchSemi = true,
                         bool UnindentWhitesmithsBraces = false);
   void parseChildBlock();
   void parsePPDirective();
   void parsePPDefine();
   void parsePPIf(bool IfDef);

clang/lib/Format/UnwrappedLineParser.cpp

 //===--- UnwrappedLineParser.cpp - Format C++ code ------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
 /// This file contains the implementation of the UnwrappedLineParser,
 /// which turns a stream of tokens into UnwrappedLines.
 ///
 //===----------------------------------------------------------------------===//
 
 #include "UnwrappedLineParser.h"
 #include "FormatToken.h"
-#include "TokenAnnotator.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 
 #include <algorithm>
 
 #define DEBUG_TYPE "format-parser"
 
bool UnwrappedLineParser::precededByCommentOrPPDirective() const {
   if (!Lines.empty() && Lines.back().InPPDirective)
     return true;
 
   const FormatToken *Previous = Tokens->getPreviousToken();
   return Previous && Previous->is(tok::comment) &&
          (Previous->IsMultiline || Previous->NewlinesBefore > 0);
 }
 
-bool UnwrappedLineParser::mightFitOnOneLine() const {
-  const auto ColumnLimit = Style.ColumnLimit;
-  if (ColumnLimit == 0)
-    return true;
-
-  if (Lines.empty())
-    return true;
-
-  const auto &PreviousLine = Lines.back();
-  const auto &Tokens = PreviousLine.Tokens;
-  assert(!Tokens.empty());
-  const auto *LastToken = Tokens.back().Tok;
-  assert(LastToken);
-  if (!LastToken->isOneOf(tok::semi, tok::comment))
-    return true;
-
-  AnnotatedLine Line(PreviousLine);
-  assert(Line.Last == LastToken);
-
-  TokenAnnotator Annotator(Style, Keywords);
-  Annotator.annotate(Line);
-  Annotator.calculateFormattingInformation(Line);
-
-  return Line.Level * Style.IndentWidth + LastToken->TotalLength <= ColumnLimit;
-}
-
 // Returns true if a simple block, or false otherwise. (A simple block has a
-// single statement that fits on a single line.)
+// single statement.)
 bool UnwrappedLineParser::parseLevel(bool HasOpeningBrace, IfStmtKind *IfKind) {
   const bool IsPrecededByCommentOrPPDirective =
       !Style.RemoveBracesLLVM || precededByCommentOrPPDirective();
   unsigned StatementCount = 0;
   bool SwitchLabelEncountered = false;
   do {
     tok::TokenKind kind = FormatTok->Tok.getKind();
     if (FormatTok->getType() == TT_MacroBlockBegin) {
case tok::r_brace:
         if (!Style.RemoveBracesLLVM)
           return false;
         if (FormatTok->isNot(tok::r_brace) || StatementCount != 1 ||
             IsPrecededByCommentOrPPDirective ||
             precededByCommentOrPPDirective()) {
           return false;
         }
         const FormatToken *Next = Tokens->peekNextToken();
-        if (Next->is(tok::comment) && Next->NewlinesBefore == 0)
-          return false;
-        return mightFitOnOneLine();
+        return Next->isNot(tok::comment) || Next->NewlinesBefore > 0;
       }
       nextToken();
       addUnwrappedLine();
       break;
     case tok::kw_default: {
       unsigned StoredPosition = Tokens->getPosition();
       FormatToken *Next;
       do {

clang/unittests/Format/FormatTest.cpp

verifyFormat("int abs = [](int i) {\n"
                "int abs = [](int i) {\n"
                "  if (i >= 0) {\n"
                "    return i;\n"
                "  }\n"
                "  return -i;\n"
                "};",
                Style);
 
+  // FIXME: See https://github.com/llvm/llvm-project/issues/53543.
+#if 0
+  Style.ColumnLimit = 65;
+
+  verifyFormat("if (condition) {\n"
+               "  ff(Indices,\n"
+               "     [&](unsigned LHSI, unsigned RHSI) { return true; });\n"
+               "} else {\n"
+               "  ff(Indices,\n"
+               "     [&](unsigned LHSI, unsigned RHSI) { return true; });\n"
+               "}",
+               Style);
+
   Style.ColumnLimit = 20;
 
   verifyFormat("if (a) {\n"
                "  b = c + // 1 -\n"
                "      d;\n"
                "}",
                Style);
 
   verifyFormat("if (a) {\n"
                "  b = c >= 0 ? d\n"
                "             : e;\n"
                "}",
                "if (a) {\n"
                "  b = c >= 0 ? d : e;\n"
                "}",
                Style);
+#endif
+
+  Style.ColumnLimit = 20;
 
   verifyFormat("if (a)\n"
                "  b = c > 0 ? d : e;",
                "if (a) {\n"
                "  b = c > 0 ? d : e;\n"
                "}",
                Style);