[clang-format] keep TypeScript argument decorators in line

As a follow-up from https://reviews.llvm.org/D108538, ensure TypeScript
argument decorators are kept in line with the argument.

Reviewed By: MyDeveloperDay

Differential Revision: https://reviews.llvm.org/D108620

Author: krasimirgg

clang/lib/Format/ContinuationIndenter.cpp

@@ -19,6 +19,7 @@
 #include "clang/Basic/OperatorPrecedence.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Format/Format.h"
+#include "llvm/ADT/StringSet.h"
 #include "llvm/Support/Debug.h"
 
 #define DEBUG_TYPE "format-indenter"
@@ -492,8 +493,12 @@ bool ContinuationIndenter::mustBreak(const LineState &State) {
       return true;
   }
 
-  // Break after the closing parenthesis of TypeScript decorators.
+  // Break after the closing parenthesis of TypeScript decorators before
+  // functions, getters and setters.
+  static const llvm::StringSet<> BreakBeforeDecoratedTokens = {"get", "set",
+                                                               "function"};
   if (Style.Language == FormatStyle::LK_JavaScript &&
+      BreakBeforeDecoratedTokens.contains(Current.TokenText) &&
       Previous.is(tok::r_paren) && Previous.is(TT_JavaAnnotation)) {
     return true;
   }

clang/unittests/Format/FormatTestJS.cpp

@@ -701,15 +701,37 @@ TEST_F(FormatTestJS, FormatsFreestandingFunctions) {
                    getGoogleJSStyleWithColumns(20)));
 }
 
-TEST_F(FormatTestJS, FormatsDecoratedFunctions) {
-  // Regression test: ensure that there is a break before `get`.
+TEST_F(FormatTestJS, FormatsDecorators) {
+  // No line break after argument decorators.
+  verifyFormat("class A {\n"
+               "  constructor(@arg(DECOR) private arg: Type) {}\n"
+               "}");
+  // Ensure that there is a break before functions, getters and setters.
   EXPECT_EQ("class A {\n"
             "  private p = () => {}\n"
             "\n"
             "  @decorated('a')\n"
             "  get f() {\n"
             "    return result;\n"
             "  }\n"
+            "}\n"
+            "\n"
+            "class B {\n"
+            "  private p = () => {}\n"
+            "\n"
+            "  @decorated('a')\n"
+            "  set f() {\n"
+            "    return result;\n"
+            "  }\n"
+            "}\n"
+            "\n"
+            "class C {\n"
+            "  private p = () => {}\n"
+            "\n"
+            "  @decorated('a')\n"
+            "  function f() {\n"
+            "    return result;\n"
+            "  }\n"
             "}",
             format("class A {\n"
                    "  private p = () => {}\n"
@@ -718,6 +740,24 @@ TEST_F(FormatTestJS, FormatsDecoratedFunctions) {
                    "  get f() {\n"
                    "    return result;\n"
                    "  }\n"
+                   "}\n"
+                   "\n"
+                   "class B {\n"
+                   "  private p = () => {}\n"
+                   "\n"
+                   "  @decorated('a')\n"
+                   "  set f() {\n"
+                   "    return result;\n"
+                   "  }\n"
+                   "}\n"
+                   "\n"
+                   "class C {\n"
+                   "  private p = () => {}\n"
+                   "\n"
+                   "  @decorated('a')\n"
+                   "  function f() {\n"
+                   "    return result;\n"
+                   "  }\n"
                    "}",
                    getGoogleJSStyleWithColumns(50)));
 }