clang-format: Fix C99 designated initializers corner cases

[Typz]

Summary

This fixes the missing space before the designated initializer when Cpp11BracedListStyle=false :

const struct A a = { .a = 1, .b = 2 };
                    ^

Also, wrapping between opening brace and designated array initializers used to have an excessive penalty (like breaking between an expression and the subscript operator), leading to unexpected wrapping:

const struct Aaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaa =
    {[1] = aaaaaaaaaaaaaaaaaaaaaaaaaaa,
     [2] = bbbbbbbbbbbbbbbbbbbbbbbbbbb};

instead of:

const struct Aaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaa = {
    [1] = aaaaaaaaaaaaaaaaaaaaaaaaaaa,
    [2] = bbbbbbbbbbbbbbbbbbbbbbbbbbb};

Finally, designated array initializers are not binpacked, just like designated member initializers.

[Typz]

No fix yet, just wondering if this is an actual issue or the expected behavior.

unittests/Format/FormatTest.cpp

1526

don't know why this test does not pass similarly to similar one with designated member access: in this case, clang-format puts each member in column.

[Typz]

Implement fix

[Typz]

Seems there is a special exception to BinPacking in case of designated member initializers.
Should BinPacking be disabled also in case of designated array initializers?

[Typz]

Fix incorrect labelling as ObjCMethodExpr
Do not binpack designated array initializers, just like designated member initializers

[Typz]

ping

[djasper]

lib/Format/TokenAnnotator.cpp

339

Use Style.isCpp().

unittests/Format/FormatTest.cpp

1526

I don't understand what you mean here.

[Typz]

Fix review comments

unittests/Format/FormatTest.cpp

1526

I did not understand why designated member access [line 1516] was wrapped, while this did not happen with designated array access; but since then I have found out, and updated the code to handle designated array accesses similarly.

[djasper]

Looks good.

lib/Format/ContinuationIndenter.cpp

if (Current.isOneOf(tok::l_brace, TT_ArrayInitializerLSquare)) {
     const FormatToken *NextNoComment = Current.getNextNonComment();
     bool EndsInComma = Current.MatchingParen &&
                        Current.MatchingParen->Previous &&
                        Current.MatchingParen->Previous->is(tok::comma);
     AvoidBinPacking =
         (Current.is(TT_ArrayInitializerLSquare) && EndsInComma) ||
         Current.is(TT_DictLiteral) ||
         Style.Language == FormatStyle::LK_Proto || !Style.BinPackArguments ||
-        (NextNoComment && NextNoComment->is(TT_DesignatedInitializerPeriod));
+        (NextNoComment &&
+         NextNoComment->isOneOf(TT_DesignatedInitializerPeriod,
+                                TT_DesignatedInitializerLSquare));
     if (Current.ParameterCount > 1)
       NestedBlockIndent = std::max(NestedBlockIndent, State.Column + 1);
   } else {
     NewIndent = Style.ContinuationIndentWidth +
                 std::max(State.Stack.back().LastSpace,
                          State.Stack.back().StartOfFunctionCall);
 
     // Ensure that different different brackets force relative alignment, e.g.:

lib/Format/FormatToken.h

#define LIST_TOKEN_TYPES \
   TYPE(BlockComment) \
   TYPE(CastRParen) \
   TYPE(ConditionalExpr) \
   TYPE(ConflictAlternative) \
   TYPE(ConflictEnd) \
   TYPE(ConflictStart) \
   TYPE(CtorInitializerColon) \
   TYPE(CtorInitializerComma) \
+  TYPE(DesignatedInitializerLSquare) \
   TYPE(DesignatedInitializerPeriod) \
   TYPE(DictLiteral) \
   TYPE(ForEachMacro) \
   TYPE(FunctionAnnotationRParen) \
   TYPE(FunctionDeclarationName) \
   TYPE(FunctionLBrace) \
   TYPE(FunctionTypeLParen) \
   TYPE(ImplicitStringLiteral) \

lib/Format/TokenAnnotator.cpp

bool parseSquare() {
     unsigned BindingIncrease = 1;
     if (Left->is(TT_Unknown)) {
       if (StartsObjCMethodExpr) {
         Left->Type = TT_ObjCMethodExpr;
       } else if (Style.Language == FormatStyle::LK_JavaScript && Parent &&
                  Contexts.back().ContextKind == tok::l_brace &&
                  Parent->isOneOf(tok::l_brace, tok::comma)) {
         Left->Type = TT_JsComputedPropertyName;
+      } else if (Style.isCpp() && Contexts.back().ContextKind == tok::l_brace &&
+                 Parent && Parent->isOneOf(tok::l_brace, tok::comma)) {
+        Left->Type = TT_DesignatedInitializerLSquare;
       } else if (CurrentToken->is(tok::r_square) && Parent &&
                  Parent->is(TT_TemplateCloser)) {
         Left->Type = TT_ArraySubscriptLSquare;
       } else if (Style.Language == FormatStyle::LK_Proto ||
                  (!CppArrayTemplates && Parent &&
                   Parent->isOneOf(TT_BinaryOperator, TT_TemplateCloser, tok::at,
                                   tok::comma, tok::l_paren, tok::l_square,
                                   tok::question, tok::colon, tok::kw_return,
while (CurrentToken) {
             Contexts.back().FirstObjCSelectorName->LongestObjCSelectorName = 0;
         }
         next();
         return true;
       }
       if (CurrentToken->isOneOf(tok::r_paren, tok::r_brace))
         return false;
       if (CurrentToken->is(tok::colon)) {
-        if (Left->is(TT_ArraySubscriptLSquare)) {
+        if (Left->isOneOf(TT_ArraySubscriptLSquare,
+                          TT_DesignatedInitializerLSquare)) {
           Left->Type = TT_ObjCMethodExpr;
           StartsObjCMethodExpr = true;
           Contexts.back().ColonIsObjCMethodExpr = true;
           if (Parent && Parent->is(tok::r_paren))
             Parent->Type = TT_CastRParen;
         }
         ColonFound = true;
       }
if (Right.is(tok::l_square)) {
     if (Style.Language == FormatStyle::LK_Proto)
       return 1;
     if (Left.is(tok::r_square))
       return 200;
     // Slightly prefer formatting local lambda definitions like functions.
     if (Right.is(TT_LambdaLSquare) && Left.is(tok::equal))
       return 35;
     if (!Right.isOneOf(TT_ObjCMethodExpr, TT_LambdaLSquare,
-                       TT_ArrayInitializerLSquare))
+                       TT_ArrayInitializerLSquare,
+                       TT_DesignatedInitializerLSquare))
       return 500;
   }
 
   if (Right.isOneOf(TT_StartOfName, TT_FunctionDeclarationName) ||
       Right.is(tok::kw_operator)) {
     if (Line.startsWith(tok::kw_for) && Right.PartOfMultiVariableDeclStmt)
       return 3;
     if (Left.is(TT_StartOfName))
return (Left.is(TT_ArrayInitializerLSquare) &&
             Right.isNot(tok::r_square));
   if (Right.is(tok::r_square))
     return Right.MatchingParen &&
            ((Style.SpacesInContainerLiterals &&
              Right.MatchingParen->is(TT_ArrayInitializerLSquare)) ||
             (Style.SpacesInSquareBrackets &&
              Right.MatchingParen->is(TT_ArraySubscriptLSquare)));
   if (Right.is(tok::l_square) &&
-      !Right.isOneOf(TT_ObjCMethodExpr, TT_LambdaLSquare) &&
+      !Right.isOneOf(TT_ObjCMethodExpr, TT_LambdaLSquare,
+                     TT_DesignatedInitializerLSquare) &&
       !Left.isOneOf(tok::numeric_constant, TT_DictLiteral))
     return false;
   if (Left.is(tok::l_brace) && Right.is(tok::r_brace))
     return !Left.Children.empty(); // No spaces in "{}".
   if ((Left.is(tok::l_brace) && Left.BlockKind != BK_Block) ||
       (Right.is(tok::r_brace) && Right.MatchingParen &&
        Right.MatchingParen->BlockKind != BK_Block))
     return !Style.Cpp11BracedListStyle;
bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
   // incorrectly classified the parenthesis as a cast. FIXME: Detect correctly.
   if (Left.is(TT_CastRParen))
     return Style.SpaceAfterCStyleCast ||
            Right.isOneOf(TT_BinaryOperator, TT_SelectorName);
 
   if (Left.is(tok::greater) && Right.is(tok::greater))
     return Right.is(TT_TemplateCloser) && Left.is(TT_TemplateCloser) &&
            (Style.Standard != FormatStyle::LS_Cpp11 || Style.SpacesInAngles);
-  if (Right.isOneOf(tok::arrow, tok::period, tok::arrowstar, tok::periodstar) ||
-      Left.isOneOf(tok::arrow, tok::period, tok::arrowstar, tok::periodstar))
+  if (Right.isOneOf(tok::arrow, tok::arrowstar, tok::periodstar) ||
+      Left.isOneOf(tok::arrow, tok::period, tok::arrowstar, tok::periodstar) ||
+      (Right.is(tok::period) && Right.isNot(TT_DesignatedInitializerPeriod)))
     return false;
   if (!Style.SpaceBeforeAssignmentOperators &&
       Right.getPrecedence() == prec::Assignment)
     return false;
   if (Right.is(tok::coloncolon) && Left.is(tok::identifier))
     // Generally don't remove existing spaces between an identifier and "::".
     // The identifier might actually be a macro name such as ALWAYS_INLINE. If
     // this turns out to be too lenient, add analysis of the identifier itself.

unittests/Format/FormatTest.cpp

TEST_F(FormatTest, DesignatedInitializers) {
   verifyFormat("const struct Aaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaa = {\n"
                "    .aaaaaaaaaaaaaaaaaaaaaaaaaaa = 1,\n"
                "    .bbbbbbbbbbbbbbbbbbbbbbbbbbb = 2,\n"
                "    .ccccccccccccccccccccccccccc = 3,\n"
                "    .ddddddddddddddddddddddddddd = 4,\n"
                "    .eeeeeeeeeeeeeeeeeeeeeeeeeee = 5};");
 
   verifyGoogleFormat("const struct A a = {.a = 1, .b = 2};");
+
+  verifyFormat("const struct A a = {[0] = 1, [1] = 2};");
+  verifyFormat("const struct A a = {[1] = aaaaaaaaaa,\n"
+               "                    [2] = bbbbbbbbbb,\n"
+               "                    [3] = cccccccccc,\n"
+               "                    [4] = dddddddddd,\n"
+               "                    [5] = eeeeeeeeee};");
+  verifyFormat("const struct Aaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaa = {\n"
+               "    [1] = aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,\n"
+               "    [2] = bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb,\n"
+               "    [3] = cccccccccccccccccccccccccccccccccccccc,\n"
+               "    [4] = dddddddddddddddddddddddddddddddddddddd,\n"
+               "    [5] = eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee};");
 }
 
 TEST_F(FormatTest, NestedStaticInitializers) {
   verifyFormat("static A x = {{{}}};\n");
   verifyFormat("static A x = {{{init1, init2, init3, init4},\n"
                "               {init1, init2, init3, init4}}};",
                getLLVMStyleWithColumns(50));
 
TEST_F(FormatTest, LayoutCxx11BraceInitializers) {
   verifyFormat("return {arg1, SomeType{parameter}};");
   verifyFormat("int count = set<int>{f(), g(), h()}.size();");
   verifyFormat("new T{arg1, arg2};");
   verifyFormat("f(MyMap[{composite, key}]);");
   verifyFormat("class Class {\n"
                "  T member = {arg1, arg2};\n"
                "};");
   verifyFormat("vector<int> foo = {::SomeGlobalFunction()};");
+  verifyFormat("const struct A a = {.a = 1, .b = 2};");
+  verifyFormat("const struct A a = {[0] = 1, [1] = 2};");
   verifyFormat("static_assert(std::is_integral<int>{} + 0, \"\");");
   verifyFormat("int a = std::is_integral<int>{} + 0;");
 
   verifyFormat("int foo(int i) { return fo1{}(i); }");
   verifyFormat("int foo(int i) { return fo1{}(i); }");
   verifyFormat("auto i = decltype(x){};");
   verifyFormat("std::vector<int> v = {1, 0 /* comment */};");
   verifyFormat("Node n{1, Node{1000}, //\n"
verifyFormat("std::vector<MyValues> aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa{\n"
                "    aaaaaaaaaa,\n"
                "    a,\n"
                "    aaaaaaaaaaaaaaaaaaaaa,\n"
                "    aaaaaaaaaaaa,\n"
                "    aaaaaaaaaaaaaaaaaaa + aaaaaaaaaaaaaaaaaaa,\n"
                "    aaaaaaa,\n"
                "    a};");
   verifyFormat("vector<int> foo = { ::SomeGlobalFunction() };", ExtraSpaces);
+  verifyFormat("const struct A a = { .a = 1, .b = 2 };", ExtraSpaces);
+  verifyFormat("const struct A a = { [0] = 1, [1] = 2 };", ExtraSpaces);
 }
 
 TEST_F(FormatTest, FormatsBracedListsInColumnLayout) {
   verifyFormat("vector<int> x = {1, 22, 333, 4444, 55555, 666666, 7777777,\n"
                "                 1, 22, 333, 4444, 55555, 666666, 7777777,\n"
                "                 1, 22, 333, 4444, 55555, 666666, 7777777,\n"
                "                 1, 22, 333, 4444, 55555, 666666, 7777777,\n"
                "                 1, 22, 333, 4444, 55555, 666666, 7777777,\n"