[clang-format] PR50326 AlignAfterOpenBracket AlwaysBreak does not keep to the ColumnLimit

[MyDeveloperDay]

Summary

https://bugs.llvm.org/show_bug.cgi?id=50326

D93626: [clang-format] PR48535 clang-format Incorrectly Removes Space After C Style Cast When Type Is Not a Pointer caused a regression in terms of formatting a function ptr, incorrectly thinking it was a C-Style cast.

This cased a formatter regression between clang-format-11 and clang-format-12

void bar()
{
    size_t foo = function(Foooo, Barrrrr, Foooo, Barrrr, FoooooooooLooooong);

    size_t foo = function(
        Foooo, Barrrrr, Foooo, Barrrr, FoooooooooLooooong, BarrrrrrrrrrrrLong,
        FoooooooooLooooong);

    size_t foo = (*(function))(Foooo, Barrrrr, Foooo, FoooooooooLooooong);

    size_t foo = (*(
        function))(Foooo, Barrrrr, Foooo, Barrrr, FoooooooooLooooong,
        BarrrrrrrrrrrrLong, FoooooooooLooooong);
}

became

void bar()
{
    size_t foo1 = function(Foooo, Barrrrr, Foooo, Barrrr, FoooooooooLooooong);

    size_t foo2 = function(
        Foooo, Barrrrr, Foooo, Barrrr, FoooooooooLooooong, BarrrrrrrrrrrrLong,
        FoooooooooLooooong);

    size_t foo3 = (*(function))(Foooo, Barrrrr, Foooo, FoooooooooLooooong);

    size_t foo4 = (*(
        function))(Foooo, Barrrrr, Foooo, Barrrr, FoooooooooLooooong, BarrrrrrrrrrrrLong, FoooooooooLooooong);
}

This fixes this issue by simplify the clause to be specific about what is wanted rather than what is not.

[curdeius]

LGTM. Not blocking, but I'd add foo4 example from the description as a test case (with a link to the bug maybe).

[HazardyKnusperkeks]

I second that ColumnLimit breaking test case. :)

[MyDeveloperDay]

In D102392#2756779, @curdeius wrote:

LGTM. Not blocking, but I'd add foo4 example from the description as a test case (with a link to the bug maybe).

Of course I should have added that too! let me do that!

[MyDeveloperDay]

Add a test that shows it no longer impacts function ptrs

[MyDeveloperDay]

slightly closer test to the original failure

[MyDeveloperDay]

This is also the cause of https://bugs.llvm.org/show_bug.cgi?id=49995, we might want to ask for this to be put into any 12.0.1 patch, I'm not sure who we need to speak to about getting something put into a patch @benhamilton, @probinson

clang/lib/Format/TokenAnnotator.cpp

for (const FormatToken *Token = Tok.MatchingParen->Next; Token != &Tok;
       if (Token->is(TT_BinaryOperator))
         return false;
 
     // If the following token is an identifier or 'this', this is a cast. All
     // cases where this can be something else are handled above.
     if (Tok.Next->isOneOf(tok::identifier, tok::kw_this))
       return true;
 
-    if (Tok.Next->is(tok::l_paren) &&
-        !(Tok.Previous && Tok.Previous->is(tok::identifier) &&
-          Tok.Previous->Previous &&
-          Tok.Previous->Previous->isOneOf(tok::arrowstar, tok::arrow,
-                                          tok::star)))
+    // Look for a cast `( x ) (`.
+    if (Tok.Next->is(tok::l_paren) && Tok.Previous && Tok.Previous->Previous) {
+      if (Tok.Previous->is(tok::identifier) &&
+          Tok.Previous->Previous->is(tok::l_paren))
         return true;
+    }
 
     if (!Tok.Next->Next)
       return false;
 
     // If the next token after the parenthesis is a unary operator, assume
     // that this is cast, unless there are unexpected tokens inside the
     // parenthesis.
     bool NextIsUnary =

clang/unittests/Format/FormatTest.cpp

verifyFormat("do {\n"
                Spaces);
 
   verifyFormat("size_t idx = (size_t) (ptr - ((char *) file));", Spaces);
   verifyFormat("size_t idx = (size_t) a;", Spaces);
   verifyFormat("size_t idx = (size_t) (a - 1);", Spaces);
   verifyFormat("size_t idx = (a->*foo)(a - 1);", Spaces);
   verifyFormat("size_t idx = (a->foo)(a - 1);", Spaces);
   verifyFormat("size_t idx = (*foo)(a - 1);", Spaces);
+  verifyFormat("size_t idx = (*(foo))(a - 1);", Spaces);
+  Spaces.ColumnLimit = 80;
+  Spaces.IndentWidth = 4;
+  Spaces.AlignAfterOpenBracket = FormatStyle::BAS_AlwaysBreak;
+  verifyFormat("void foo( ) {\n"
+               "    size_t foo = (*(function))(\n"
+               "        Foooo, Barrrrr, Foooo, Barrrr, FoooooooooLooooong, "
+               "BarrrrrrrrrrrrLong,\n"
+               "        FoooooooooLooooong);\n"
+               "}",
+               Spaces);
   Spaces.SpaceAfterCStyleCast = false;
   verifyFormat("size_t idx = (size_t)(ptr - ((char *)file));", Spaces);
   verifyFormat("size_t idx = (size_t)a;", Spaces);
   verifyFormat("size_t idx = (size_t)(a - 1);", Spaces);
   verifyFormat("size_t idx = (a->*foo)(a - 1);", Spaces);
   verifyFormat("size_t idx = (a->foo)(a - 1);", Spaces);
   verifyFormat("size_t idx = (*foo)(a - 1);", Spaces);
+  verifyFormat("size_t idx = (*(foo))(a - 1);", Spaces);
+
+  verifyFormat("void foo( ) {\n"
+               "    size_t foo = (*(function))(\n"
+               "        Foooo, Barrrrr, Foooo, Barrrr, FoooooooooLooooong, "
+               "BarrrrrrrrrrrrLong,\n"
+               "        FoooooooooLooooong);\n"
+               "}",
+               Spaces);
 }
 
 TEST_F(FormatTest, ConfigurableSpacesInSquareBrackets) {
   verifyFormat("int a[5];");
   verifyFormat("a[3] += 42;");
 
   FormatStyle Spaces = getLLVMStyle();
   Spaces.SpacesInSquareBrackets = true;