[clang-format] Stop breaking unbreakable strings in JS (#66168)

Dictionary literal keys and strings in TypeScript type declarations can
not be broken.

The problem was pointed out by @alexfh and @e-kud here:

https://reviews.llvm.org/D154093#4644512

Author: sstwcw

clang/lib/Format/ContinuationIndenter.cpp

@@ -2241,6 +2241,12 @@ ContinuationIndenter::createBreakableToken(const FormatToken &Current,
     if (Style.isJson() || !Style.BreakStringLiterals || !AllowBreak)
       return nullptr;
 
+    // Strings in TypeScript types and dictionary keys can not be broken.
+    if (Style.isJavaScript() && (Current.is(TT_SelectorName) ||
+                                 State.Line->startsWith(Keywords.kw_type))) {
+      return nullptr;
+    }
+
     // Don't break string literals inside preprocessor directives (except for
     // #define directives, as their contents are stored in separate lines and
     // are not affected by this check).

clang/unittests/Format/FormatTestJS.cpp

@@ -1596,6 +1596,28 @@ TEST_F(FormatTestJS, StringLiteralConcatenation) {
                "var literal = `xxxxxx ${xxxxxxxxxxxxxxxxxxxxxx + "
                "xxxxxxxxxxxxxxxxxxxxxx} xxxxxx`;",
                getGoogleJSStyleWithColumns(14));
+
+  // Strings in a TypeScript type declaration can't be broken.
+  verifyFormat("type x =\n"
+               "    'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';",
+               getGoogleJSStyleWithColumns(20));
+  verifyFormat("/* type */ type x =\n"
+               "    'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';",
+               getGoogleJSStyleWithColumns(20));
+  // Dictionary keys can't be broken. Values can be broken.
+  verifyFormat("var w = {\n"
+               "  'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx':\n"
+               "      'xxxxxxxxxx' +\n"
+               "      'xxxxxxxxxx' +\n"
+               "      'xxxxxxxxxx' +\n"
+               "      'xxxxxxxxxx' +\n"
+               "      'xxx',\n"
+               "};",
+               "var w = {\n"
+               "  'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx':\n"
+               "      'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',\n"
+               "};",
+               getGoogleJSStyleWithColumns(20));
 }
 
 TEST_F(FormatTestJS, RegexLiteralClassification) {

clang/unittests/Format/TokenAnnotatorTest.cpp

@@ -2040,6 +2040,25 @@ TEST_F(TokenAnnotatorTest, UnderstandDesignatedInitializers) {
   EXPECT_TOKEN(Tokens[13], tok::period, TT_DesignatedInitializerPeriod);
 }
 
+TEST_F(TokenAnnotatorTest, UnderstandsJavaScript) {
+  auto Annotate = [this](llvm::StringRef Code) {
+    return annotate(Code, getLLVMStyle(FormatStyle::LK_JavaScript));
+  };
+
+  // Dictionary.
+  auto Tokens = Annotate("var x = {'x' : 1, 'y' : 2};");
+  ASSERT_EQ(Tokens.size(), 14u) << Tokens;
+  EXPECT_TOKEN(Tokens[3], tok::l_brace, TT_DictLiteral);
+  EXPECT_TOKEN(Tokens[4], tok::string_literal, TT_SelectorName);
+  EXPECT_TOKEN(Tokens[5], tok::colon, TT_DictLiteral);
+  EXPECT_TOKEN(Tokens[8], tok::string_literal, TT_SelectorName);
+  EXPECT_TOKEN(Tokens[9], tok::colon, TT_DictLiteral);
+  // Change when we need to annotate these.
+  EXPECT_BRACE_KIND(Tokens[3], BK_Unknown);
+  EXPECT_BRACE_KIND(Tokens[11], BK_Unknown);
+  EXPECT_TOKEN(Tokens[11], tok::r_brace, TT_Unknown);
+}
+
 } // namespace
 } // namespace format
 } // namespace clang