[clang-format] Don't break multi block parameters on ObjCBreakBeforeNestedBlockParam

[ghvg1313]

Summary

While the original diff makes a lot of sense, and multiple inline block parameter/trailing paramemter after inline block paramemter should be discouraged, the formatting result is different than what xcode does by default
For the exact same example provided in the original diff:

[object
  blockArgument:^{
    a = 42;
  }
     anotherArg:42];

The code is hard to read and not very visually pleasing

This diff uses ObjCBreakBeforeNestedBlockParam to shield from the formatting
When it's set to false, don't allign the inline block paramemters.

[jolesiak]

Makes sense, thanks for patching this!

[ghvg1313]

• Fix documentation formatting

[ghvg1313]

reset diff's base

[ghvg1313]

@jolesiak I don't yet have the commit access, do you mind help merging this diff? Thanks

[MyDeveloperDay]

what is changing in clang/docs/ClangFormatStyleOptions.rst? if nothing then remove from the diff

[ghvg1313]

In D77039#1967224, @MyDeveloperDay wrote:

what is changing in clang/docs/ClangFormatStyleOptions.rst? if nothing then remove from the diff

there's an indentation issue, this changes the example of the doc from:

- (void)_aMethod
     {
        [self.test1 t:self
                     w:self
            callback:^(typeof(self) self, NSNumber *u, NSNumber *v) {
                u = c;
             }]
}

to

- (void)_aMethod
{
   [self.test1 t:self
               w:self
        callback:^(typeof(self) self, NSNumber *u, NSNumber *v) {
            u = c;
        }]
}

clang/docs/ClangFormatStyleOptions.rst

- (void)_aMethod
          [self.test1 t:self w:self callback:^(typeof(self) self, NSNumber *u, NSNumber *v) {
              u = c;
          }]
      }
      true:
      - (void)_aMethod
      {
         [self.test1 t:self
-                     w:self
              callback:^(typeof(self) self, NSNumber *u, NSNumber *v) {
                  u = c;
              }]
      }
 
 **ObjCSpaceAfterProperty** (``bool``)
   Add a space after ``@property`` in Objective-C, i.e. use
   ``@property (readonly)`` instead of ``@property(readonly)``.
 

clang/lib/Format/ContinuationIndenter.cpp

bool ContinuationIndenter::mustBreak(const LineState &State) {
   if (Current.MustBreakBefore || Current.is(TT_InlineASMColon))
     return true;
   if (State.Stack.back().BreakBeforeClosingBrace &&
       Current.closesBlockOrBlockTypeList(Style))
     return true;
   if (Previous.is(tok::semi) && State.LineContainsContinuedForLoopSection)
     return true;
   if (Style.Language == FormatStyle::LK_ObjC &&
+      Style.ObjCBreakBeforeNestedBlockParam &&
       Current.ObjCSelectorNameParts > 1 &&
       Current.startsSequence(TT_SelectorName, tok::colon, tok::caret)) {
     return true;
   }
   // Avoid producing inconsistent states by requiring breaks where they are not
   // permitted for C# generic type constraints.
   if (State.Stack.back().IsCSharpGenericTypeConstraint &&
       Previous.isNot(TT_CSharpGenericTypeConstraintComma))

clang/unittests/Format/FormatTestObjC.cpp

TEST_F(FormatTestObjC, BreakLineBeforeNestedBlockParam) {
 
   verifyFormat("[self.test1 t:self w:self callback:^(typeof(self) self, "
                "NSNumber *u, NSNumber *v) {\n"
                "  u = c;\n"
                "} w:self callback2:^(typeof(self) self, NSNumber *a, NSNumber "
                "*b, NSNumber *c) {\n"
                "  b = c;\n"
                "}]");
+  verifyFormat("[self.test1 t:self w:self callback:^(typeof(self) self, "
+               "NSNumber *u, NSNumber *v) {\n"
+               "  u = v;\n"
+               "} z:self]");
 
   Style.ColumnLimit = 80;
   verifyFormat(
       "[self.test_method a:self b:self\n"
       "           callback:^(typeof(self) self, NSNumber *u, NSNumber *v) {\n"
       "             u = v;\n"
       "           }]");
 }
 
 } // end namespace
 } // end namespace format
 } // end namespace clang