[clang-format] Fix aligning of java-style declarations

[eoanermine]

Summary

• Modify TokenAnnotator to work fine with java-style array declarations
• Add test for aligning of java declarations

Closes https://github.com/llvm/llvm-project/issues/55931

[eoanermine]

I found that the problem was that TokenAnnotator doesn't handle Java-style array declarations fine. It doesn't consider identifier after square brackets as a StartOfName (see github issue for more context).

I fixed it, it seems valid, but I'm not a hundred percent sure about it.

[eoanermine]

I don't have an access to commit the patch by myself.

clang/lib/Format/TokenAnnotator.cpp

bool isStartOfName(const FormatToken &Tok) {
     // *a or &a or &&a.
     if (PreviousNotConst->is(TT_PointerOrReference))
       return true;
 
     // MyClass a;
     if (PreviousNotConst->isSimpleTypeSpecifier())
       return true;
 
+    // type[] a in Java
+    if (Style.Language == FormatStyle::LK_Java &&
+        PreviousNotConst->is(tok::r_square))
+      return true;
+
     // const a = in JavaScript.
     return Style.isJavaScript() && PreviousNotConst->is(tok::kw_const);
   }
 
   /// Determine whether '(' is starting a C++ cast.
   bool lParenStartsCppCast(const FormatToken &Tok) {
     // C-style casts are only used in C++.
     if (!Style.isCpp())

clang/unittests/Format/FormatTestJava.cpp

EXPECT_EQ("/*\n"
             "void f() {}",
             format("  /*\n"
                    "   * Really multi-line\n"
                    "   * comment.\n"
                    "   */\n"
                    "  void f() {}"));
 }
 
+TEST_F(FormatTestJava, AlignDeclarations) {
+  FormatStyle Style = getLLVMStyle(FormatStyle::LK_Java);
+  Style.AlignConsecutiveDeclarations.Enabled = true;
+  verifyFormat("private final String[]       args;\n"
+               "private final A_ParserHelper parserHelper;\n"
+               "private final int            numOfCmdArgs;\n"
+               "private int                  numOfCmdArgs;\n"
+               "private String[]             args;",
+               Style);
+}
+
 TEST_F(FormatTestJava, KeepsDelimitersOnOwnLineInJavaDocComments) {
   EXPECT_EQ("/**\n"
             " * javadoc line 1\n"
             " * javadoc line 2\n"
             " */",
             format("/** javadoc line 1\n"
                    " * javadoc line 2 */"));
 }