.clang-tidy

# Copyright 2020 Toyota Research Institute.  All rights reserved.
#
# clang-tidy lists all rules in a single YAML string, which makes it
# hard to have inline comments.  Thus we'll add comments out-of-line
# up here.
#
# Disabled checks have rationale documented here.

# * cert-err58-cpp - This verifies that exceptions are not thrown
#   during static initialization or destruction.  However, boost::test
#   violates this, so we leave it off for now.

# * cert-err60-cpp - This requires that exception types have noexcept
#   copy constructors.  SystemError could do so, except that it
#   contains a std::string, which can throw std::bad_alloc.  Hopefully
#   soon C++ will delete std::bad_alloc entirely, but in the meantime,
#   we disable this check.

# * cppcoreguidelines-pro-type-vararg,hicpp-vararg - boost::test uses
#   varargs, so for now we leave this disabled globally

# * cppcoreguidelines-pro-bounds-array-to-pointer-decay,
#   hicpp-no-array-decay - every call to BOOST_ASSERT_MSG triggers
#   this along with things like using std::cout

# * cppcoreguidelines-pro-type-reinterpret-cast - we currently have a
#   lot of reinterpret_casts that are required in order to perform low
#   level bit manipulation.  It probably isn't worth annotating all of
#   them yet.

# * cppcoreguidelines-pro-bounds-pointer-arithmetic - until we get
#   C++20's span or some similar construct, this will be difficult to
#   satisfy.

# * fuchsia-default-arguments - we currently permit C++ default
#   arguments

# * fuchsia-multiple-inheritance - we currently permit inheriting
#   implementation and multiple inheritance

# * fuchsia-overloaded-operator - we (and GSG) consider operator
#   overloading fine

# * fuchsia-statically-constructed-objects - boost::test uses
#   statically constructed objects, so we leave this around.

# * google-runtime-references - boost::asio widely uses the convention
#   of passing io_service by mutable reference, as does the C++
#   iostreams library

# * hicpp-exception-baseclass - either boost::system::system_error
#   doesn't inherit from std::exception or clang can't discover that
#   it does.  In either case, this isn't important enough to figure
#   out.

# * readability-named-parameter - This requires that all parameters be
#   named.  This rule seems to be of dubious value, since often the
#   type alone of an argument is sufficient documentation.

# * readability-redundant-declaration - C++14 requires static
#   constexpr class members to have a separate definition.  Until we
#   drop C++14 support, it is easiest to just ignore this warning.

# * performance-unnecessary-copy-initialization,
#   performance-unnecessary-value-param - These checks seem to be of
#   dubious value, as the conditions they warn about would all likely
#   be optimized away by a sane compiler and they require moderate
#   contortions to satisfy.

Checks: >
    *,
    -cert-err58-cpp,
    -cert-err60-cpp,
    -cppcoreguidelines-pro-type-vararg,
    -hicpp-vararg,
    -cppcoreguidelines-pro-bounds-array-to-pointer-decay,
    -hicpp-no-array-decay,
    -cppcoreguidelines-pro-type-reinterpret-cast,
    -cppcoreguidelines-pro-bounds-pointer-arithmetic,
    -fuchsia-default-arguments,
    -fuchsia-multiple-inheritance,
    -fuchsia-overloaded-operator,
    -fuchsia-statically-constructed-objects,
    -google-runtime-references,
    -hicpp-exception-baseclass,
    -readability-named-parameter,
    -readability-redundant-declaration,
    -performance-unnecessary-copy-initialization,
    -performance-unnecessary-value-param,