[clang-format] Correctly attach enum braces with ShortEnums disabled

Previously, with AllowShortEnumsOnASingleLine disabled, enums that would have otherwise fit on a single line would always put the opening brace on its own line.
This patch ensures that these enums will only put the brace on its own line if the existing attachment rules indicate that it should.

Reviewed By: HazardyKnusperkeks, curdeius

Differential Revision: https://reviews.llvm.org/D99840

clang/docs/ReleaseNotes.rst

@@ -153,7 +153,8 @@ AST Matchers
 clang-format
 ------------
 
-- ...
+- Option ``AllowShortEnumsOnASingleLine: false`` has been improved, it now
+  correctly places the opening brace according to ``BraceWrapping.AfterEnum``.
 
 libclang
 --------

clang/include/clang/Format/Format.h

@@ -544,8 +544,7 @@ struct FormatStyle {
   ///   enum { A, B } myEnum;
   ///
   ///   false:
-  ///   enum
-  ///   {
+  ///   enum {
   ///     A,
   ///     B
   ///   } myEnum;

clang/lib/Format/UnwrappedLineParser.cpp

@@ -2515,6 +2515,8 @@ bool UnwrappedLineParser::parseEnum() {
   if (FormatTok->Tok.is(tok::kw_enum))
     nextToken();
 
+  const FormatToken &InitialToken = *FormatTok;
+
   // In TypeScript, "enum" can also be used as property name, e.g. in interface
   // declarations. An "enum" keyword followed by a colon would be a syntax
   // error and thus assume it is just an identifier.
@@ -2561,7 +2563,8 @@ bool UnwrappedLineParser::parseEnum() {
     return true;
   }
 
-  if (!Style.AllowShortEnumsOnASingleLine)
+  if (!Style.AllowShortEnumsOnASingleLine &&
+      ShouldBreakBeforeBrace(Style, InitialToken))
     addUnwrappedLine();
   // Parse enum body.
   nextToken();

clang/unittests/Format/FormatTest.cpp

@@ -2451,6 +2451,14 @@ TEST_F(FormatTest, ShortEnums) {
   Style.AllowShortEnumsOnASingleLine = true;
   verifyFormat("enum { A, B, C } ShortEnum1, ShortEnum2;", Style);
   Style.AllowShortEnumsOnASingleLine = false;
+  verifyFormat("enum {\n"
+               "  A,\n"
+               "  B,\n"
+               "  C\n"
+               "} ShortEnum1, ShortEnum2;",
+               Style);
+  Style.BreakBeforeBraces = FormatStyle::BS_Custom;
+  Style.BraceWrapping.AfterEnum = true;
   verifyFormat("enum\n"
                "{\n"
                "  A,\n"
@@ -22123,8 +22131,7 @@ TEST_F(FormatTest, IndentAccessModifiers) {
                Style);
   // Enumerations are not records and should be unaffected.
   Style.AllowShortEnumsOnASingleLine = false;
-  verifyFormat("enum class E\n"
-               "{\n"
+  verifyFormat("enum class E {\n"
                "  A,\n"
                "  B\n"
                "};\n",

clang/unittests/Format/FormatTestCSharp.cpp

@@ -402,8 +402,7 @@ TEST_F(FormatTestCSharp, CSharpRegions) {
 }
 
 TEST_F(FormatTestCSharp, CSharpKeyWordEscaping) {
-  verifyFormat("public enum var\n"
-               "{\n"
+  verifyFormat("public enum var {\n"
                "    none,\n"
                "    @string,\n"
                "    bool,\n"