clang-format regression around class declarations with attributes

[kadircet]

desired formatting:

#define ABSL_ATTRIBUTE_TRIVIAL_ABI
#define ABSL_NULLABILITY_COMPATIBLE

class ABSL_ATTRIBUTE_TRIVIAL_ABI ABSL_NULLABILITY_COMPATIBLE
    ArenaSafeUniquePtr{};

actual formatting:

#define ABSL_ATTRIBUTE_TRIVIAL_ABI
#define ABSL_NULLABILITY_COMPATIBLE

class ABSL_ATTRIBUTE_TRIVIAL_ABI
    ABSL_NULLABILITY_COMPATIBLE ArenaSafeUniquePtr {};

bisection points to #124891. it's similar to #124574 as we were putting class-name to its own line and now we're mixing it with attributes. I guess this is due to special casing ClassHeadName despite having a heuristic with false positives that determines it (e.g. in this case we're falsely treating ABSL_ATTRIBUTE_TRIVIAL_ABI as ClassHeadName).

[llvmbot]

@llvm/issue-subscribers-clang-format

Author: kadir çetinkaya (kadircet)

desired formatting: ```cpp #define ABSL_ATTRIBUTE_TRIVIAL_ABI #define ABSL_NULLABILITY_COMPATIBLE

class ABSL_ATTRIBUTE_TRIVIAL_ABI ABSL_NULLABILITY_COMPATIBLE
ArenaSafeUniquePtr{};

actual formatting:
```cpp
#define ABSL_ATTRIBUTE_TRIVIAL_ABI
#define ABSL_NULLABILITY_COMPATIBLE

class ABSL_ATTRIBUTE_TRIVIAL_ABI
    ABSL_NULLABILITY_COMPATIBLE ArenaSafeUniquePtr {};

bisection points to #124891. it's similar to #124574 as we were putting class-name to its own line and now we're mixing it with attributes. I guess this is due to special casing ClassHeadName despite having a heuristic with false positives that determines it (e.g. in this case we're falsely treating ABSL_ATTRIBUTE_TRIVIAL_ABI as ClassHeadName).

[owenca]

desired formatting:

#define ABSL_ATTRIBUTE_TRIVIAL_ABI
#define ABSL_NULLABILITY_COMPATIBLE

class ABSL_ATTRIBUTE_TRIVIAL_ABI ABSL_NULLABILITY_COMPATIBLE
ArenaSafeUniquePtr{};

Expected format is:

class ABSL_ATTRIBUTE_TRIVIAL_ABI ABSL_NULLABILITY_COMPATIBLE
    ArenaSafeUniquePtr {};

Notice that there's a space before the {.

I guess this is due to special casing ClassHeadName despite having a heuristic with false positives that determines it (e.g. in this case we're falsely treating ABSL_ATTRIBUTE_TRIVIAL_ABI as ClassHeadName).

Actually, before #124891:

AnnotatedTokens(L=0, P=0, T=6, C=0):
 M=0 C=0 T=Unknown S=1 F=0 B=0 BK=0 P=0 Name=class L=5 PPK=2 FakeLParens= FakeRParens=0 II=0x14b80d7f8 Text='class'
 M=0 C=1 T=Unknown S=1 F=0 B=0 BK=0 P=5020 Name=identifier L=32 PPK=2 FakeLParens= FakeRParens=0 II=0x14b811f08 Text='ABSL_ATTRIBUTE_TRIVIAL_ABI'
 M=0 C=1 T=StartOfName S=1 F=0 B=0 BK=0 P=220 Name=identifier L=60 PPK=2 FakeLParens= FakeRParens=0 II=0x14b811f50 Text='ABSL_NULLABILITY_COMPATIBLE'
 M=0 C=1 T=StartOfName S=1 F=0 B=0 BK=0 P=130 Name=identifier L=79 PPK=2 FakeLParens= FakeRParens=0 II=0x14b811f90 Text='ArenaSafeUniquePtr'
 M=0 C=0 T=ClassLBrace S=1 F=0 B=0 BK=1 P=23 Name=l_brace L=81 PPK=2 FakeLParens= FakeRParens=0 II=0x0 Text='{'

After that PR:

AnnotatedTokens(L=0, P=0, T=6, C=0):
 M=0 C=0 T=Unknown S=1 F=0 B=0 BK=0 P=0 Name=class L=5 PPK=2 FakeLParens= FakeRParens=0 II=0x13880a7f8 Text='class'
 M=0 C=1 T=Unknown S=1 F=0 B=0 BK=0 P=5020 Name=identifier L=32 PPK=2 FakeLParens= FakeRParens=0 II=0x13881df08 Text='ABSL_ATTRIBUTE_TRIVIAL_ABI'
 M=0 C=1 T=StartOfName S=1 F=0 B=0 BK=0 P=220 Name=identifier L=60 PPK=2 FakeLParens= FakeRParens=0 II=0x13881df50 Text='ABSL_NULLABILITY_COMPATIBLE'
 M=0 C=0 T=ClassHeadName S=1 F=0 B=0 BK=0 P=23 Name=identifier L=79 PPK=2 FakeLParens= FakeRParens=0 II=0x13881df90 Text='ArenaSafeUniquePtr'
 M=0 C=0 T=ClassLBrace S=1 F=0 B=0 BK=1 P=23 Name=l_brace L=81 PPK=2 FakeLParens= FakeRParens=0 II=0x0 Text='{'

So it got the ClassHeadName right, but didn't set C (CanBreakBefore).