[clang-format] Fix SplitEmptyRecord affecting SplitEmptyFunction.

[curdeius]

Summary

Fixes https://github.com/llvm/llvm-project/issues/50051.

Given the style:

BraceWrapping
  AfterFunction: true
 SplitEmptyFunction: true
 SplitEmptyRecord: false
...

The code that should be like:

void f(int aaaaaaaaaaaaaaaaaaaaaaaaaaaa,
       int bbbbbbbbbbbbbbbbbbbbbbbb)
{
}

gets the braces merged together:

void f(int aaaaaaaaaaaaaaaaaaaaaaaaaaaa,
       int bbbbbbbbbbbbbbbbbbbbbbbb)
{}

[MyDeveloperDay]

LGTM, less the clang-format oddities

clang/lib/Format/UnwrappedLineFormatter.cpp

if (Style.BraceWrapping.SplitEmptyRecord &&
               return 0;
           }
         }
       }
     }
 
     // Try to merge a block with left brace wrapped that wasn't yet covered
     if (TheLine->Last->is(tok::l_brace)) {
-      return !Style.BraceWrapping.AfterFunction ||
+      bool ShouldMerge = false;
+      if (TheLine->First->isOneOf(tok::kw_class, tok::kw_struct)) {
+        ShouldMerge = !Style.BraceWrapping.AfterClass ||
                       (I[1]->First->is(tok::r_brace) &&
-                      !Style.BraceWrapping.SplitEmptyRecord)
-                 ? tryMergeSimpleBlock(I, E, Limit)
-                 : 0;
+                       !Style.BraceWrapping.SplitEmptyRecord);
+      } else {
+        ShouldMerge = !Style.BraceWrapping.AfterFunction ||
+                      (I[1]->First->is(tok::r_brace) &&
+                       !Style.BraceWrapping.SplitEmptyFunction);
+      }
+      return ShouldMerge ? tryMergeSimpleBlock(I, E, Limit) : 0;
     }
     // Try to merge a function block with left brace wrapped
     if (I[1]->First->is(TT_FunctionLBrace) &&
         Style.BraceWrapping.AfterFunction) {
       if (I[1]->Last->is(TT_LineComment))
         return 0;
 
       // Check for Limit <= 2 to account for the " {".

clang/unittests/Format/FormatTest.cpp

verifyFormat("int aaaaaaaaaaaaaa(int bbbbbbbbbbbbbb)\n"
                "{}",
                Style);
   verifyFormat("int aaaaaaaaaaaaaa(int bbbbbbbbbbbbbb)\n"
                "{\n"
                "  return 0;\n"
                "}",
                Style);
 }
+
+TEST_F(FormatTest, SplitEmptyFunctionButNotRecord) {
+  FormatStyle Style = getLLVMStyle();
+  Style.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_None;
+  Style.BreakBeforeBraces = FormatStyle::BS_Custom;
+  Style.BraceWrapping.AfterFunction = true;
+  Style.BraceWrapping.SplitEmptyFunction = true;
+  Style.BraceWrapping.SplitEmptyRecord = false;
+  Style.ColumnLimit = 40;
+
+  verifyFormat("class C {};", Style);
+  verifyFormat("struct C {};", Style);
+  verifyFormat("void f(int aaaaaaaaaaaaaaaaaaaaaaaaaaaa,\n"
+               "       int bbbbbbbbbbbbbbbbbbbbbbbb)\n"
+               "{\n"
+               "}",
+               Style);
+  verifyFormat("class C {\n"
+               "  C()\n"
+               "      : aaaaaaaaaaaaaaaaaaaaaaaaaaaa(),\n"
+               "        bbbbbbbbbbbbbbbbbbb()\n"
+               "  {\n"
+               "  }\n"
+               "  void\n"
+               "  m(int aaaaaaaaaaaaaaaaaaaaaaaaaaaa,\n"
+               "    int bbbbbbbbbbbbbbbbbbbbbbbb)\n"
+               "  {\n"
+               "  }\n"
+               "};",
+               Style);
+}
+
 TEST_F(FormatTest, KeepShortFunctionAfterPPElse) {
   FormatStyle Style = getLLVMStyle();
   Style.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_All;
   verifyFormat("#ifdef A\n"
                "int f() {}\n"
                "#else\n"
                "int g() {}\n"
                "#endif",

 }
 
 // FIXME: Encode Cyrillic and CJK characters below to appease MS compilers.
 #if !defined(_MSC_VER)
 
 TEST_F(FormatTest, CountsUTF8CharactersProperly) {
   verifyFormat("\"Однажды в студёную зимнюю пору...\"",
                getLLVMStyleWithColumns(35));
-  verifyFormat("\"一 二 三 四 五 六 七 八 九 十\"",
-               getLLVMStyleWithColumns(31));
+  verifyFormat("\"一 二 三 四 五 六 七 八 九 十\"", getLLVMStyleWithColumns(31));
   verifyFormat("// Однажды в студёную зимнюю пору...",
                getLLVMStyleWithColumns(36));
   verifyFormat("// 一 二 三 四 五 六 七 八 九 十", getLLVMStyleWithColumns(32));
   verifyFormat("/* Однажды в студёную зимнюю пору... */",
                getLLVMStyleWithColumns(39));
-  verifyFormat("/* 一 二 三 四 五 六 七 八 九 十 */",
-               getLLVMStyleWithColumns(35));
+  verifyFormat("/* 一 二 三 四 五 六 七 八 九 十 */", getLLVMStyleWithColumns(35));
 }
 
 TEST_F(FormatTest, SplitsUTF8Strings) {
   // Non-printable characters' width is currently considered to be the length in
   // bytes in UTF8. The characters can be displayed in very different manner
   // (zero-width, single width with a substitution glyph, expanded to their code
   // (e.g. "<8d>"), so there's no single correct way to handle them.
   EXPECT_EQ("\"aaaaÄ\"\n"
             "\"\xc2\x8d\";",
             format("\"aaaaÄ\xc2\x8d\";", getLLVMStyleWithColumns(10)));
   EXPECT_EQ("\"aaaaaaaÄ\"\n"
             "\"\xc2\x8d\";",
             format("\"aaaaaaaÄ\xc2\x8d\";", getLLVMStyleWithColumns(10)));
   EXPECT_EQ("\"Однажды, в \"\n"
             "\"студёную \"\n"
             "\"зимнюю \"\n"
             "\"пору,\"",
             format("\"Однажды, в студёную зимнюю пору,\"",
                    getLLVMStyleWithColumns(13)));
-  EXPECT_EQ(
-      "\"一 二 三 \"\n"
+  EXPECT_EQ("\"一 二 三 \"\n"
             "\"四 五六 \"\n"
             "\"七 八 九 \"\n"
             "\"十\"",
             format("\"一 二 三 四 五六 七 八 九 十\"", getLLVMStyleWithColumns(11)));
-  EXPECT_EQ("\"一\t\"\n"
-            "\"二 \t\"\n"
-            "\"三 四 \"\n"
-            "\"五\t\"\n"
-            "\"六 \t\"\n"
-            "\"七 \"\n"
-            "\"八九十\tqq\"",
-            format("\"一\t二 \t三 四 五\t六 \t七 八九十\tqq\"",
-                   getLLVMStyleWithColumns(11)));
+  EXPECT_EQ(
+      "\"一\t\"\n"
+      format("\"一\t二 \t三 四 五\t六 \t七 八九十\tqq\"", getLLVMStyleWithColumns(11)));
 
   // UTF8 character in an escape sequence.
   EXPECT_EQ("\"aaaaaa\"\n"
             "\"\\\xC2\x8D\"",
             format("\"aaaaaa\\\xC2\x8D\"", getLLVMStyleWithColumns(10)));
 }
 
 TEST_F(FormatTest, HandlesDoubleWidthCharsInMultiLineStrings) {
EXPECT_EQ("/* Гляжу,\n"
             " * гору\n"
             " * Лошадка,\n"
             " * везущая\n"
             " * хворосту\n"
             " * воз. */",
             format("/* Гляжу, поднимается медленно в гору\n"
                    " * Лошадка, везущая хворосту воз. */",
                    getLLVMStyleWithColumns(13)));
-  EXPECT_EQ(
-      "/* 一二三\n"
+  EXPECT_EQ("/* 一二三\n"
             " * 四五六七\n"
             " * 八  九\n"
             " * 十  */",
             format("/* 一二三 四五六七 八  九 十  */", getLLVMStyleWithColumns(9)));
   EXPECT_EQ("/* 𝓣𝓮𝓼𝓽 𝔣𝔬𝔲𝔯\n"
             " * 𝕓𝕪𝕥𝕖\n"
             " * 𝖀𝕿𝕱-𝟠 */",
-            format("/* 𝓣𝓮𝓼𝓽 𝔣𝔬𝔲𝔯 𝕓𝕪𝕥𝕖 𝖀𝕿𝕱-𝟠 */", getLLVMStyleWithColumns(12)));
+            format("/* 𝓣𝓮𝓼𝓽 𝔣𝔬𝔲𝔯 𝕓𝕪𝕥𝕖 𝖀𝕿𝕱-𝟠 */",
+                   getLLVMStyleWithColumns(12)));
 }
 
 #endif // _MSC_VER
 
 TEST_F(FormatTest, ConstructorInitializerIndentWidth) {
   FormatStyle Style = getLLVMStyle();
 
   Style.ConstructorInitializerIndentWidth = 4;