[clang] 163c13f - [clang-format] Fix formatting of the code that follows C# Lambda Expressions

[Owen Pan via cfe-commits]

Author: Peter Stys
Date: 2021-12-17T10:42:15-08:00
New Revision: 163c13fed9f68c31a14b3d2409b994909f0600bb

URL: https://github.com/llvm/llvm-project/commit/163c13fed9f68c31a14b3d2409b994909f0600bb
DIFF: https://github.com/llvm/llvm-project/commit/163c13fed9f68c31a14b3d2409b994909f0600bb.diff

LOG: [clang-format] Fix formatting of the code that follows C# Lambda Expressions

The alignment fix introduced by https://reviews.llvm.org/D104388 caused a regression whereby formatting of code that follows the lambda block is incorrect i.e. separate expressions are put on the same line.

Differential Revision: https://reviews.llvm.org/D115738

Added: 
    

Modified: 
    clang/lib/Format/UnwrappedLineParser.cpp
    clang/lib/Format/UnwrappedLineParser.h
    clang/unittests/Format/FormatTestCSharp.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index 78405f23e4003..0b1771ba7c9c9 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -1941,6 +1941,22 @@ bool UnwrappedLineParser::tryToParseBracedList() {
   return true;
 }
 
+bool UnwrappedLineParser::tryToParseCSharpLambda() {
+  // Fat arrows (=>) have tok::TokenKind tok::equal but TokenType
+  // TT_FatArrow. They always start an expression or a child block if
+  // followed by a curly brace.
+  nextToken();
+  if (FormatTok->isNot(tok::l_brace))
+    return false;
+  // C# may break after => if the next character is a newline.
+  if (Style.BraceWrapping.AfterFunction) {
+    // calling `addUnwrappedLine()` here causes odd parsing errors.
+    FormatTok->MustBreakBefore = true;
+  }
+  parseChildBlock();
+  return true;
+}
+
 bool UnwrappedLineParser::parseBracedList(bool ContinueOnSemicolons,
                                           bool IsEnum,
                                           tok::TokenKind ClosingBraceKind) {
@@ -1949,23 +1965,9 @@ bool UnwrappedLineParser::parseBracedList(bool ContinueOnSemicolons,
   // FIXME: Once we have an expression parser in the UnwrappedLineParser,
   // replace this by using parseAssignmentExpression() inside.
   do {
-    if (Style.isCSharp()) {
-      // Fat arrows (=>) have tok::TokenKind tok::equal but TokenType
-      // TT_FatArrow. They always start an expression or a child block if
-      // followed by a curly brace.
-      if (FormatTok->is(TT_FatArrow)) {
-        nextToken();
-        if (FormatTok->is(tok::l_brace)) {
-          // C# may break after => if the next character is a newline.
-          if (Style.isCSharp() && Style.BraceWrapping.AfterFunction == true) {
-            // calling `addUnwrappedLine()` here causes odd parsing errors.
-            FormatTok->MustBreakBefore = true;
-          }
-          parseChildBlock();
-          continue;
-        }
-      }
-    }
+    if (Style.isCSharp() && FormatTok->is(TT_FatArrow))
+      if (tryToParseCSharpLambda())
+        continue;
     if (Style.Language == FormatStyle::LK_JavaScript) {
       if (FormatTok->is(Keywords.kw_function) ||
           FormatTok->startsSequence(Keywords.kw_async, Keywords.kw_function)) {
@@ -2092,7 +2094,7 @@ void UnwrappedLineParser::parseParens() {
       break;
     case tok::equal:
       if (Style.isCSharp() && FormatTok->is(TT_FatArrow))
-        parseStructuralElement();
+        tryToParseCSharpLambda();
       else
         nextToken();
       break;

diff  --git a/clang/lib/Format/UnwrappedLineParser.h b/clang/lib/Format/UnwrappedLineParser.h
index b4c0826545971..3c07fbf2e8d36 100644
--- a/clang/lib/Format/UnwrappedLineParser.h
+++ b/clang/lib/Format/UnwrappedLineParser.h
@@ -138,6 +138,7 @@ class UnwrappedLineParser {
   // https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/where-generic-type-constraint
   void parseCSharpGenericTypeConstraint();
   bool tryToParseLambda();
+  bool tryToParseCSharpLambda();
   bool tryToParseLambdaIntroducer();
   bool tryToParsePropertyAccessor();
   void tryToParseJSFunction();

diff  --git a/clang/unittests/Format/FormatTestCSharp.cpp b/clang/unittests/Format/FormatTestCSharp.cpp
index 78547e07d2150..2cfec61d8f94b 100644
--- a/clang/unittests/Format/FormatTestCSharp.cpp
+++ b/clang/unittests/Format/FormatTestCSharp.cpp
@@ -759,6 +759,128 @@ class MyClass
                GoogleStyle);
 }
 
+TEST_F(FormatTestCSharp, CSharpLambdasDontBreakFollowingCodeAlignment) {
+  FormatStyle GoogleStyle = getGoogleStyle(FormatStyle::LK_CSharp);
+  FormatStyle MicrosoftStyle = getMicrosoftStyle(FormatStyle::LK_CSharp);
+
+  verifyFormat(R"(//
+public class Sample
+{
+    public void Test()
+    {
+        while (true)
+        {
+            preBindEnumerators.RemoveAll(enumerator => !enumerator.MoveNext());
+            CodeThatFollowsLambda();
+            IsWellAligned();
+        }
+    }
+})",
+               MicrosoftStyle);
+
+  verifyFormat(R"(//
+public class Sample {
+  public void Test() {
+    while (true) {
+      preBindEnumerators.RemoveAll(enumerator => !enumerator.MoveNext());
+      CodeThatFollowsLambda();
+      IsWellAligned();
+    }
+  }
+})",
+               GoogleStyle);
+}
+
+TEST_F(FormatTestCSharp, CSharpLambdasComplexLambdasDontBreakAlignment) {
+  FormatStyle GoogleStyle = getGoogleStyle(FormatStyle::LK_CSharp);
+  FormatStyle MicrosoftStyle = getMicrosoftStyle(FormatStyle::LK_CSharp);
+
+  verifyFormat(R"(//
+public class Test
+{
+    private static void ComplexLambda(BuildReport protoReport)
+    {
+        allSelectedScenes =
+            veryVeryLongCollectionNameThatPutsTheLineLenghtAboveTheThresholds.Where(scene => scene.enabled)
+                .Select(scene => scene.path)
+                .ToArray();
+        if (allSelectedScenes.Count == 0)
+        {
+            return;
+        }
+        Functions();
+        AreWell();
+        Aligned();
+        AfterLambdaBlock();
+    }
+})",
+               MicrosoftStyle);
+
+  verifyFormat(R"(//
+public class Test {
+  private static void ComplexLambda(BuildReport protoReport) {
+    allSelectedScenes = veryVeryLongCollectionNameThatPutsTheLineLenghtAboveTheThresholds
+                            .Where(scene => scene.enabled)
+                            .Select(scene => scene.path)
+                            .ToArray();
+    if (allSelectedScenes.Count == 0) {
+      return;
+    }
+    Functions();
+    AreWell();
+    Aligned();
+    AfterLambdaBlock();
+  }
+})",
+               GoogleStyle);
+}
+
+TEST_F(FormatTestCSharp, CSharpLambdasMulipleLambdasDontBreakAlignment) {
+  FormatStyle GoogleStyle = getGoogleStyle(FormatStyle::LK_CSharp);
+  FormatStyle MicrosoftStyle = getMicrosoftStyle(FormatStyle::LK_CSharp);
+
+  verifyFormat(R"(//
+public class Test
+{
+    private static void MultipleLambdas(BuildReport protoReport)
+    {
+        allSelectedScenes =
+            veryVeryLongCollectionNameThatPutsTheLineLenghtAboveTheThresholds.Where(scene => scene.enabled)
+                .Select(scene => scene.path)
+                .ToArray();
+        preBindEnumerators.RemoveAll(enumerator => !enumerator.MoveNext());
+        if (allSelectedScenes.Count == 0)
+        {
+            return;
+        }
+        Functions();
+        AreWell();
+        Aligned();
+        AfterLambdaBlock();
+    }
+})",
+               MicrosoftStyle);
+
+  verifyFormat(R"(//
+public class Test {
+  private static void MultipleLambdas(BuildReport protoReport) {
+    allSelectedScenes = veryVeryLongCollectionNameThatPutsTheLineLenghtAboveTheThresholds
+                            .Where(scene => scene.enabled)
+                            .Select(scene => scene.path)
+                            .ToArray();
+    preBindEnumerators.RemoveAll(enumerator => !enumerator.MoveNext());
+    if (allSelectedScenes.Count == 0) {
+      return;
+    }
+    Functions();
+    AreWell();
+    Aligned();
+    AfterLambdaBlock();
+  }
+})",
+               GoogleStyle);
+}
+
 TEST_F(FormatTestCSharp, CSharpObjectInitializers) {
   FormatStyle Style = getGoogleStyle(FormatStyle::LK_CSharp);