.clang-tidy

---
# Adapted from: https://github.com/googleapis/google-cloud-cpp/blob/main/.clang-tidy
# Configure clang-tidy for this project.

# Here is an explanation for why some of the checks are disabled (but can be reconsidered):
#  -google-explicit-constructor: Does not recognize `explicit(false)`
#      https://github.com/llvm/llvm-project/issues/53115
#
#  -google-readability-namespace-comments: the *_CLIENT_NS is a macro, and
#      clang-tidy fails to match it against the initial value.
#
#  -modernize-use-trailing-return-type: clang-tidy recommends using
#      `auto Foo() -> std::string { return ...; }`, we think the code is less
#      readable in this form.
#
#  -modernize-return-braced-init-list: We think removing typenames and using
#      only braced-init can hurt readability.
#
#  -modernize-avoid-c-arrays: We only use C arrays when they seem to be the
#      right tool for the job, such as `char foo[] = "hello"`. In these cases,
#      avoiding C arrays often makes the code less readable, and std::array is
#      not a drop-in replacement because it doesn't deduce the size.
#
#  -performance-move-const-arg: This warning requires the developer to
#      know/care more about the implementation details of types/functions than
#      should be necessary. For example, `A a; F(std::move(a));` will trigger a
#      warning IFF `A` is a trivial type (and therefore the move is
#      meaningless). It would also warn if `F` accepts by `const&`, which is
#      another detail that the caller need not care about.
#
#  -performance-enum-size: Smaller enums may or not may be faster, it depends on
#      the architechture. If data size was a consideration, we might decide to
#      enable the warnings.
#
#  -readability-function-cognitive-complexity: too many false positives with
#      clang-tidy-12. We need to disable this check in macros, and that setting
#      only appears in clang-tidy-13.
#
#  -readability-suspicious-call-argument: too many false positives.
#
#  -bugprone-easily-swappable-parameters: too many false positives.
#
#  -bugprone-unchecked-optional-access: too many false positives in tests.
#     Despite what the documentation says, this warning appears after
#     `ASSERT_TRUE(variable)` or `ASSERT_TRUE(variable.has_value())`.
#  -bugprone-switch-missing-default-case: conflicts with `-Wcovered-switch-default`
Checks: >
  -*,
  abseil-*,
  bugprone-*,
  google-*,
  misc-*,
  modernize-*,
  performance-*,
  portability-*,
  readability-*,
  -google-explicit-constructor,
  -google-readability-namespace-comments,
  -google-readability-todo,
  -misc-non-private-member-variables-in-classes,
  -modernize-pass-by-value,
  -modernize-return-braced-init-list,
  -modernize-use-default-member-init,
  -modernize-use-trailing-return-type,
  -modernize-avoid-c-arrays,
  -performance-move-const-arg,
  -performance-enum-size,
  -readability-function-cognitive-complexity,
  -readability-magic-numbers,
  -readability-redundant-access-specifiers,
  -readability-redundant-member-init,
  -readability-suspicious-call-argument,
  -bugprone-easily-swappable-parameters,
  -bugprone-switch-missing-default-case,
  -bugprone-unchecked-optional-access,
  -readability-container-size-empty,
  -bugprone-crtp-constructor-accessibility,

# Turn all the warnings from the checks above into errors.
WarningsAsErrors: "*"

HeaderFilterRegex: ".*"

CheckOptions:
  - { key: readability-identifier-naming.NamespaceCase,               value: lower_case   }
  - { key: readability-identifier-naming.ClassCase,                   value: CamelCase    }
  - { key: readability-identifier-naming.StructCase,                  value: CamelCase    }
  - { key: readability-identifier-naming.TypeTemplateParameterCase,   value: CamelCase    }
  - { key: readability-identifier-naming.ValueTemplateParameterCase,  value: UPPER_CASE   }
  - { key: readability-identifier-naming.FunctionCase,                value: lower_case   }
  - { key: readability-identifier-naming.VariableCase,                value: lower_case   }
  - { key: readability-identifier-naming.ParameterCase,               value: lower_case   }
  - { key: readability-identifier-naming.ClassMemberCase,             value: lower_case   }
  - { key: readability-identifier-naming.ClassMemberSuffix,           value: _            }
  - { key: readability-identifier-naming.PrivateMemberSuffix,         value: _            }
  - { key: readability-identifier-naming.ProtectedMemberSuffix,       value: _            }
  - { key: readability-identifier-naming.EnumConstantCase,            value: UPPER_CASE   }
  - { key: readability-identifier-naming.ConstexprVariableCase,       value: UPPER_CASE   }
  - { key: readability-identifier-naming.GlobalConstantCase,          value: UPPER_CASE   }
  - { key: readability-identifier-naming.MemberConstantCase,          value: UPPER_CASE   }
  - { key: readability-identifier-naming.StaticConstantCase,          value: UPPER_CASE   }
  - { key: readability-identifier-length.IgnoredVariableNames,        value: "^[_]$"      }