clang-format SpaceBeforeParens: Always is not always always

[urnathan]

clang-format doesn't always seem to format a space between 'identifier (...' when the docs suggest it should:

Here's an input that I have purposefully spaced at odds with clang-format's behaviour -- it is explicitly inserting spaces as expected, or removing them as unexpected.

#define M() 1
#if M () && defined (X) && __has_include ("bob") && __has_cpp_attribute (Y)
#define F(...) __VA_OPT__(__VA_ARGS__)
#endif
void f(){return F(__builtin_LINE () + __builtin_FOO());}

zathras:49> clang-format --style='{BasedOnStyle: LLVM, SpaceBeforeParens: Always}' fmt.cc
#define M() 1
#if M() && defined(X) && __has_include("bob") && __has_cpp_attribute(Y)
#define F(...) __VA_OPT__ (__VA_ARGS__)
#endif
void f () { return F (__builtin_LINE() + __builtin_FOO ()); }

1. That #if line doesn't insert a space after any of the function-like macro-ish invocations.
2. The __VA_OPT__ ( invocation does (as expected)
3. Known builtin __builtin_LINE() has no space, but a random __builtin_FOO () does

The same behaviour with BasedOnStyle: GNU, which of course expects the space in these places.

I'd expect a space in all these cases.

(There is no space in the function-like macro definitions, of course)

[llvmbot]

@llvm/issue-subscribers-clang-format

[mkurdej]

Review for the known builtins issue is here: https://reviews.llvm.org/D125085.

[mkurdej]

The builtins issue has been fixed in commit 85ec8a9.
For the problem with preprocessor directives (#if M() that should be #if M ()), that will be a breaking change.
We have at least a test for it here:

llvm-project/clang/unittests/Format/FormatTest.cpp

Lines 15065 to 15067 in 91b24b0

	verifyFormat("#if defined(x)\n"
	"#endif",
	Space);