[clang-format] New BreakInheritanceList style AfterComma

This inheritance list style has been widely adopted by Symantec,
a division of Broadcom Inc. It breaks after the commas that
separate the base-specifiers:

    class Derived : public Base1,
                    private Base2
    {
    };

Differential Revision: https://reviews.llvm.org/D103204

clang/docs/ClangFormatStyleOptions.rst

@@ -2038,6 +2038,15 @@ the configuration (without a prefix: ``Auto``).
            Base2
        {};
 
+  * ``BILS_AfterComma`` (in configuration: ``AfterComma``)
+    Break inheritance list only after the commas.
+
+    .. code-block:: c++
+
+       class Foo : Base1,
+                   Base2
+       {};
+
 
 
 **BreakStringLiterals** (``bool``)

clang/docs/ReleaseNotes.rst

@@ -250,6 +250,9 @@ clang-format
   accepts ``AllIfsAndElse`` value that allows to put "else if" and "else" short
   statements on a single line. (Fixes https://llvm.org/PR50019.)
 
+- Option ``BreakInheritanceList`` gets a new style, ``AfterComma``. It breaks
+  only after the commas that separate the base-specifiers.
+
 - ``git-clang-format`` no longer formats changes to symbolic links. (Fixes
   https://llvm.org/PR46992.)
 

clang/include/clang/Format/Format.h

@@ -1829,7 +1829,14 @@ struct FormatStyle {
     ///        Base2
     ///    {};
     /// \endcode
-    BILS_AfterColon
+    BILS_AfterColon,
+    /// Break inheritance list only after the commas.
+    /// \code
+    ///    class Foo : Base1,
+    ///                Base2
+    ///    {};
+    /// \endcode
+    BILS_AfterComma,
   };
 
   /// The inheritance list style to use.

clang/lib/Format/Format.cpp

@@ -240,6 +240,7 @@ struct ScalarEnumerationTraits<FormatStyle::BreakInheritanceListStyle> {
     IO.enumCase(Value, "BeforeColon", FormatStyle::BILS_BeforeColon);
     IO.enumCase(Value, "BeforeComma", FormatStyle::BILS_BeforeComma);
     IO.enumCase(Value, "AfterColon", FormatStyle::BILS_AfterColon);
+    IO.enumCase(Value, "AfterComma", FormatStyle::BILS_AfterComma);
   }
 };
 

clang/lib/Format/TokenAnnotator.cpp

@@ -3639,6 +3639,9 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
   if (Style.BreakInheritanceList == FormatStyle::BILS_BeforeComma &&
       Right.is(TT_InheritanceComma))
     return true;
+  if (Style.BreakInheritanceList == FormatStyle::BILS_AfterComma &&
+      Left.is(TT_InheritanceComma))
+    return true;
   if (Right.is(tok::string_literal) && Right.TokenText.startswith("R\""))
     // Multiline raw string literals are special wrt. line breaks. The author
     // has made a deliberate choice and might have aligned the contents of the

clang/unittests/Format/FormatTest.cpp

@@ -2290,6 +2290,28 @@ TEST_F(FormatTest, BreakInheritanceStyle) {
                "    public aaaaaaaaaaaaaaaaaaa< // break\n"
                "        aaaaaaaaaaaaaaaa> {};",
                StyleWithInheritanceBreakAfterColon);
+
+  FormatStyle StyleWithInheritanceBreakAfterComma = getLLVMStyle();
+  StyleWithInheritanceBreakAfterComma.BreakInheritanceList =
+      FormatStyle::BILS_AfterComma;
+  verifyFormat("class MyClass : public X {};",
+               StyleWithInheritanceBreakAfterComma);
+  verifyFormat("class MyClass : public X,\n"
+               "                public Y {};",
+               StyleWithInheritanceBreakAfterComma);
+  verifyFormat(
+      "class AAAAAAAAAAAAAAAAAAAAAA : public BBBBBBBBBBBBBBBBBBBBBBBBBBBBBB,\n"
+      "                               public CCCCCCCCCCCCCCCCCCCCCCCCCCCCCC "
+      "{};",
+      StyleWithInheritanceBreakAfterComma);
+  verifyFormat("struct aaaaaaaaaaaaa : public aaaaaaaaaaaaaaaaaaa< // break\n"
+               "                           aaaaaaaaaaaaaaaa> {};",
+               StyleWithInheritanceBreakAfterComma);
+  verifyFormat("class AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\n"
+               "    : public OnceBreak,\n"
+               "      public AlwaysBreak,\n"
+               "      EvenBasesFitInOneLine {};",
+               StyleWithInheritanceBreakAfterComma);
 }
 
 TEST_F(FormatTest, FormatsVariableDeclarationsAfterStructOrClass) {
@@ -5585,6 +5607,12 @@ TEST_F(FormatTest, BreakConstructorInitializersAfterColon) {
       "  public aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,\n"
       "  public bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb {};",
       Style);
+  Style.BreakInheritanceList = FormatStyle::BILS_AfterComma;
+  verifyFormat(
+      "class SomeClass\n"
+      "  : public aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,\n"
+      "    public bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb {};",
+      Style);
 }
 
 #ifndef EXPENSIVE_CHECKS
@@ -13505,6 +13533,12 @@ TEST_F(FormatTest, ConfigurableSpaceBeforeColon) {
                "}\n"
                "}",
                InheritanceStyle);
+  InheritanceStyle.BreakInheritanceList = FormatStyle::BILS_AfterComma;
+  verifyFormat("class Foooooooooooooooooooooo\n"
+               "    : public aaaaaaaaaaaaaaaaaa,\n"
+               "      public bbbbbbbbbbbbbbbbbb {\n"
+               "}",
+               InheritanceStyle);
   InheritanceStyle.BreakInheritanceList = FormatStyle::BILS_AfterColon;
   verifyFormat("class Foooooooooooooooooooooo:\n"
                "    public aaaaaaaaaaaaaaaaaa,\n"
@@ -16843,6 +16877,8 @@ TEST_F(FormatTest, ParsesConfiguration) {
               BreakConstructorInitializers, FormatStyle::BCIS_BeforeComma);
 
   Style.BreakInheritanceList = FormatStyle::BILS_BeforeColon;
+  CHECK_PARSE("BreakInheritanceList: AfterComma", BreakInheritanceList,
+              FormatStyle::BILS_AfterComma);
   CHECK_PARSE("BreakInheritanceList: BeforeComma", BreakInheritanceList,
               FormatStyle::BILS_BeforeComma);
   CHECK_PARSE("BreakInheritanceList: AfterColon", BreakInheritanceList,