Index: clang/docs/ClangFormatStyleOptions.rst
===================================================================
--- clang/docs/ClangFormatStyleOptions.rst
+++ clang/docs/ClangFormatStyleOptions.rst
@@ -3886,6 +3886,23 @@
              bbbbbbbbbbbbbbbbbbbb(),
              cccccccccccccccccccc()
 
+  * ``PCIS_OnlyNextLine`` (in configuration: ``OnlyNextLine``)
+    Put all constructor initializers on the next line if they fit.
+    Otherwise, put each one on its own line.
+
+    .. code-block:: c++
+
+       Constructor()
+           : a(), b()
+
+       Constructor()
+           : aaaaaaaaaaaaaaaaaaaa(), bbbbbbbbbbbbbbbbbbbb(), ddddddddddddd()
+
+       Constructor()
+           : aaaaaaaaaaaaaaaaaaaa(),
+             bbbbbbbbbbbbbbbbbbbb(),
+             cccccccccccccccccccc()
+
 
 
 .. _PenaltyBreakAssignment:
Index: clang/include/clang/Format/Format.h
===================================================================
--- clang/include/clang/Format/Format.h
+++ clang/include/clang/Format/Format.h
@@ -2929,6 +2929,21 @@
     ///          cccccccccccccccccccc()
     /// \endcode
     PCIS_NextLine,
+    /// Put all constructor initializers on the next line if they fit.
+    /// Otherwise, put each one on its own line.
+    /// \code
+    ///    Constructor()
+    ///        : a(), b()
+    ///
+    ///    Constructor()
+    ///        : aaaaaaaaaaaaaaaaaaaa(), bbbbbbbbbbbbbbbbbbbb(), ddddddddddddd()
+    ///
+    ///    Constructor()
+    ///        : aaaaaaaaaaaaaaaaaaaa(),
+    ///          bbbbbbbbbbbbbbbbbbbb(),
+    ///          cccccccccccccccccccc()
+    /// \endcode
+    PCIS_OnlyNextLine,
   };
 
   /// The pack constructor initializers style to use.
Index: clang/lib/Format/ContinuationIndenter.cpp
===================================================================
--- clang/lib/Format/ContinuationIndenter.cpp
+++ clang/lib/Format/ContinuationIndenter.cpp
@@ -1053,13 +1053,16 @@
     bool PreviousIsBreakingCtorInitializerColon =
         PreviousNonComment && PreviousNonComment->is(TT_CtorInitializerColon) &&
         Style.BreakConstructorInitializers == FormatStyle::BCIS_AfterColon;
+    bool AllowAllConstructorInitializersOnNextLine =
+        Style.PackConstructorInitializers == FormatStyle::PCIS_NextLine ||
+        Style.PackConstructorInitializers == FormatStyle::PCIS_OnlyNextLine;
     if (!(Previous.isOneOf(tok::l_paren, tok::l_brace, TT_BinaryOperator) ||
           PreviousIsBreakingCtorInitializerColon) ||
         (!Style.AllowAllParametersOfDeclarationOnNextLine &&
          State.Line->MustBeDeclaration) ||
         (!Style.AllowAllArgumentsOnNextLine &&
          !State.Line->MustBeDeclaration) ||
-        (Style.PackConstructorInitializers != FormatStyle::PCIS_NextLine &&
+        (!AllowAllConstructorInitializersOnNextLine &&
          PreviousIsBreakingCtorInitializerColon) ||
         Previous.is(TT_DictLiteral)) {
       CurrentState.BreakBeforeParameter = true;
@@ -1069,7 +1072,7 @@
     // and we allow all arguments on the next line, we should not break
     // before the next parameter.
     if (PreviousIsBreakingCtorInitializerColon &&
-        Style.PackConstructorInitializers == FormatStyle::PCIS_NextLine) {
+        AllowAllConstructorInitializersOnNextLine) {
       CurrentState.BreakBeforeParameter = false;
     }
   }
@@ -1400,8 +1403,9 @@
     CurrentState.NestedBlockIndent = CurrentState.Indent;
     if (Style.PackConstructorInitializers > FormatStyle::PCIS_BinPack) {
       CurrentState.AvoidBinPacking = true;
-      CurrentState.BreakBeforeParameter =
-          Style.PackConstructorInitializers != FormatStyle::PCIS_NextLine;
+      CurrentState.BreakBeforeParameter = !(
+          Style.PackConstructorInitializers == FormatStyle::PCIS_NextLine ||
+          Style.PackConstructorInitializers == FormatStyle::PCIS_OnlyNextLine);
     } else {
       CurrentState.BreakBeforeParameter = false;
     }
Index: clang/lib/Format/Format.cpp
===================================================================
--- clang/lib/Format/Format.cpp
+++ clang/lib/Format/Format.cpp
@@ -443,6 +443,7 @@
     IO.enumCase(Value, "BinPack", FormatStyle::PCIS_BinPack);
     IO.enumCase(Value, "CurrentLine", FormatStyle::PCIS_CurrentLine);
     IO.enumCase(Value, "NextLine", FormatStyle::PCIS_NextLine);
+    IO.enumCase(Value, "OnlyNextLine", FormatStyle::PCIS_OnlyNextLine);
   }
 };
 
Index: clang/lib/Format/TokenAnnotator.cpp
===================================================================
--- clang/lib/Format/TokenAnnotator.cpp
+++ clang/lib/Format/TokenAnnotator.cpp
@@ -4576,6 +4576,18 @@
       Right.isOneOf(TT_CtorInitializerComma, TT_CtorInitializerColon)) {
     return true;
   }
+  if (Style.PackConstructorInitializers == FormatStyle::PCIS_OnlyNextLine) {
+    if ((Style.BreakConstructorInitializers == FormatStyle::BCIS_BeforeColon ||
+         Style.BreakConstructorInitializers == FormatStyle::BCIS_BeforeComma) &&
+        Right.is(TT_CtorInitializerColon)) {
+      return true;
+    }
+
+    if (Style.BreakConstructorInitializers == FormatStyle::BCIS_AfterColon &&
+        Left.is(TT_CtorInitializerColon)) {
+      return true;
+    }
+  }
   // Break only if we have multiple inheritance.
   if (Style.BreakInheritanceList == FormatStyle::BILS_BeforeComma &&
       Right.is(TT_InheritanceComma)) {
Index: clang/unittests/Format/ConfigParseTest.cpp
===================================================================
--- clang/unittests/Format/ConfigParseTest.cpp
+++ clang/unittests/Format/ConfigParseTest.cpp
@@ -400,6 +400,8 @@
               PackConstructorInitializers, FormatStyle::PCIS_CurrentLine);
   CHECK_PARSE("PackConstructorInitializers: NextLine",
               PackConstructorInitializers, FormatStyle::PCIS_NextLine);
+  CHECK_PARSE("PackConstructorInitializers: OnlyNextLine",
+              PackConstructorInitializers, FormatStyle::PCIS_OnlyNextLine);
   // For backward compatibility:
   CHECK_PARSE("BasedOnStyle: Google\n"
               "ConstructorInitializerAllOnOneLineOrOnePerLine: true\n"
Index: clang/unittests/Format/FormatTest.cpp
===================================================================
--- clang/unittests/Format/FormatTest.cpp
+++ clang/unittests/Format/FormatTest.cpp
@@ -7289,6 +7289,14 @@
                  Style);
     verifyFormat("Constructor() : a(a), b(b) {}", Style);
 
+    Style.PackConstructorInitializers = FormatStyle::PCIS_OnlyNextLine;
+    verifyFormat("Constructor()\n"
+                 "    : aaaaaaaaaaaaaaaaaaaa(a), bbbbbbbbbbbbbbbbbbbbb(b) {}",
+                 Style);
+    verifyFormat("Constructor()\n"
+                 "    : a(a), b(b) {}",
+                 Style);
+
     Style.BreakConstructorInitializers = FormatStyle::BCIS_BeforeColon;
     Style.PackConstructorInitializers = FormatStyle::PCIS_NextLine;
     verifyFormat("Constructor()\n"
@@ -7301,6 +7309,11 @@
                  "      bbbbbbbbbbbbbbbbbbbbb(b) {}",
                  Style);
 
+    Style.PackConstructorInitializers = FormatStyle::PCIS_OnlyNextLine;
+    verifyFormat("Constructor()\n"
+                 "    : aaaaaaaaaaaaaaaaaaaa(a), bbbbbbbbbbbbbbbbbbbbb(b) {}",
+                 Style);
+
     Style.BreakConstructorInitializers = FormatStyle::BCIS_AfterColon;
     Style.PackConstructorInitializers = FormatStyle::PCIS_NextLine;
     verifyFormat("Constructor() :\n"
@@ -7312,6 +7325,11 @@
                  "    aaaaaaaaaaaaaaaaaa(a),\n"
                  "    bbbbbbbbbbbbbbbbbbbbb(b) {}",
                  Style);
+
+    Style.PackConstructorInitializers = FormatStyle::PCIS_OnlyNextLine;
+    verifyFormat("Constructor() :\n"
+                 "    aaaaaaaaaaaaaaaaaa(a), bbbbbbbbbbbbbbbbbbbbb(b) {}",
+                 Style);
   }
 
   // Test interactions between AllowAllParametersOfDeclarationOnNextLine and
@@ -7319,6 +7337,7 @@
   // BreakConstructorInitializers modes
   Style.BreakConstructorInitializers = FormatStyle::BCIS_BeforeComma;
   Style.AllowAllParametersOfDeclarationOnNextLine = true;
+  Style.PackConstructorInitializers = FormatStyle::PCIS_CurrentLine;
   verifyFormat("SomeClassWithALongName::Constructor(\n"
                "    int aaaaaaaaaaaaaaaaaaaaaaaa, int bbbbbbbbbbbbb)\n"
                "    : aaaaaaaaaaaaaaaaaaaa(a)\n"
@@ -7333,6 +7352,14 @@
                "    : aaaaaaaaaaaaaaaaaaaa(a), bbbbbbbbbbbbbbbbbbbbb(b) {}",
                Style);
 
+  Style.PackConstructorInitializers = FormatStyle::PCIS_OnlyNextLine;
+  verifyFormat("SomeClassWithALongName::Constructor(\n"
+               "    int aaaaaaaaaaaaaaaaaaaaaaaa,\n"
+               "    int bbbbbbbbbbbbb,\n"
+               "    int cccccccccccccccc)\n"
+               "    : aaaaaaaaaaaaaaaaaaaa(a), bbbbbbbbbbbbbbbbbbbbb(b) {}",
+               Style);
+
   Style.AllowAllParametersOfDeclarationOnNextLine = false;
   Style.PackConstructorInitializers = FormatStyle::PCIS_CurrentLine;
   verifyFormat("SomeClassWithALongName::Constructor(\n"
@@ -7359,6 +7386,14 @@
                "    : aaaaaaaaaaaaaaaaaaaa(a), bbbbbbbbbbbbbbbbbbbbb(b) {}",
                Style);
 
+  Style.PackConstructorInitializers = FormatStyle::PCIS_OnlyNextLine;
+  verifyFormat("SomeClassWithALongName::Constructor(\n"
+               "    int aaaaaaaaaaaaaaaaaaaaaaaa,\n"
+               "    int bbbbbbbbbbbbb,\n"
+               "    int cccccccccccccccc)\n"
+               "    : aaaaaaaaaaaaaaaaaaaa(a), bbbbbbbbbbbbbbbbbbbbb(b) {}",
+               Style);
+
   Style.AllowAllParametersOfDeclarationOnNextLine = false;
   Style.PackConstructorInitializers = FormatStyle::PCIS_CurrentLine;
   verifyFormat("SomeClassWithALongName::Constructor(\n"
@@ -7384,6 +7419,14 @@
                "    aaaaaaaaaaaaaaaaaaaa(a), bbbbbbbbbbbbbbbbbbbbb(b) {}",
                Style);
 
+  Style.PackConstructorInitializers = FormatStyle::PCIS_OnlyNextLine;
+  verifyFormat("SomeClassWithALongName::Constructor(\n"
+               "    int aaaaaaaaaaaaaaaaaaaaaaaa,\n"
+               "    int bbbbbbbbbbbbb,\n"
+               "    int cccccccccccccccc) :\n"
+               "    aaaaaaaaaaaaaaaaaaaa(a), bbbbbbbbbbbbbbbbbbbbb(b) {}",
+               Style);
+
   Style.AllowAllParametersOfDeclarationOnNextLine = false;
   Style.PackConstructorInitializers = FormatStyle::PCIS_CurrentLine;
   verifyFormat("SomeClassWithALongName::Constructor(\n"
@@ -7587,6 +7630,16 @@
       "    aaaaaaaaaaaaa(aaaaaaaaaaaaaa), aaaaaaaaaaaaaaa(aaaaaaaaaaaa) {}",
       Style);
 
+  Style.PackConstructorInitializers = FormatStyle::PCIS_OnlyNextLine;
+  verifyFormat(
+      "SomeClass::Constructor() :\n"
+      "    aaaaaaaaaaaaa(aaaaaaaaaaaaaa), aaaaaaaaaaaaaaa(aaaaaaaaaaaa) {}",
+      Style);
+  verifyFormat(
+      "SomeClass::Constructor() : // NOLINT\n"
+      "    aaaaaaaaaaaaa(aaaaaaaaaaaaaa), aaaaaaaaaaaaaaa(aaaaaaaaaaaa) {}",
+      Style);
+
   Style.PackConstructorInitializers = FormatStyle::PCIS_BinPack;
   verifyFormat(
       "SomeClass::Constructor() :\n"
@@ -7845,6 +7898,8 @@
     input += "           a,\n";
   input += "           a) {}";
   verifyFormat(input, OnePerLine);
+  OnePerLine.PackConstructorInitializers = FormatStyle::PCIS_OnlyNextLine;
+  verifyFormat(input, OnePerLine);
 }
 #endif
 
@@ -20884,6 +20939,19 @@
       "SomeClass::Constructor()\n"
       "    : aaaaaaaa(aaaaaaaa), aaaaaaaa(aaaaaaaa), aaaaaaaa(aaaaaaaa) {}",
       Style);
+  Style.PackConstructorInitializers = FormatStyle::PCIS_OnlyNextLine;
+  verifyFormat("SomeClass::Constructor()\n"
+               "    : aaaaaaaa(aaaaaaaa) {}",
+               Style);
+  verifyFormat("SomeClass::Constructor()\n"
+               "    : aaaaa(aaaaa), aaaaa(aaaaa), aaaaa(aaaaa)\n",
+               Style);
+  verifyFormat(
+      "SomeClass::Constructor()\n"
+      "    : aaaaaaaa(aaaaaaaa), aaaaaaaa(aaaaaaaa), aaaaaaaa(aaaaaaaa) {}",
+      Style);
+
+  Style.PackConstructorInitializers = FormatStyle::PCIS_NextLine;
   Style.ConstructorInitializerIndentWidth = 4;
   Style.ColumnLimit = 60;
   verifyFormat("SomeClass::Constructor()\n"
@@ -20891,6 +20959,12 @@
                "    , aaaaaaaa(aaaaaaaa)\n"
                "    , aaaaaaaa(aaaaaaaa) {}",
                Style);
+  Style.PackConstructorInitializers = FormatStyle::PCIS_OnlyNextLine;
+  verifyFormat("SomeClass::Constructor()\n"
+               "    : aaaaaaaa(aaaaaaaa)\n"
+               "    , aaaaaaaa(aaaaaaaa)\n"
+               "    , aaaaaaaa(aaaaaaaa) {}",
+               Style);
 }
 
 TEST_F(FormatTest, ConstructorInitializersWithPreprocessorDirective) {