.clang-tidy

# Reasoning
# =========
#
# Selection of Checks
# ------------------
#
# Selecting the following general purpose checks relevant for C code:
# - clang-analyzer-* ()
# - bugprone-*
# - readability-*
# - misc-*
#
# Additional checks for other languages or specific to projects/coding standards
# are not used, expected for the Linux kernel coding conventions, as the RIOT
# coding conventions builds upon the Linux coding conventions.
#
# Finally, the following checks are disabled:
# - bugprone-reserved-identifier:
#       Too many false positives, as check does not take `static` declaration
#       into account
# - bugprone-easily-swappable-parameters:
#       This cannot be avoided
# - bugprone-too-small-loop-variable:
#       Too many false positives
#
#
# Which Warnings to Raise to Errors
# ---------------------------------
#
# - bugprone-*:
#       Avoiding known pitfalls or explicitly adding a magic comment and a
#       reasoning for why sticking with a footgun should be doable
# - portability-*:
#       Porability issues bite us hard due to the wide varity of board,
#       toolchains, standard C libs, etc. we use. So we should avoid them
#       where possible
#
#
# Fine Tuning
# -----------
#
# - readability-function-cognitive-complexity.IgnoreMacros: `true`:
#       Otherwise the use of `DEBUG()` will be penalized, even though it
#       helps both with debugging and with documenting the code.
# - readability-identifier-length:
#       Disabled because of too many false positives.. E.g., `fd` for file
#       descriptors or `id` for IDs will be flagged, but are sensible variables
#       names when the scope is the function body
# - readability-magic-numbers:
#       Disabled because of too many false positives. E.g. in
#       ```
#       size_t byte_pos = bitpos / 8;
#       size_t byte_mask = 1U << (bitpos & 7);
#       ```
#       the numbers `8` and `7` are considered to be magic, but the code is
#       still self-explanatory. Adding `#define BITS_PER_BYTE 8` and
#       `#define BIT_POS_IN_BYTE_MASK 7` to silence the warning would not
#       improve the readability here, but instead reduce it.
# - readability-implicit-bool-conversion:
#       Conversion to bool is well defined and happens in a lot of places. With
#       this enabled, the source code in the editor lights up like a christmas
#       tree due to the amount of warnings.
# - bugprone-narrowing-conversions:
#       This warning is too aggressive: Even when returning e.g. a compile time
#       constant that is known to fit the return type of a function, a simple
#       `return FOO;` will get a warning. But using `return (some_type)FOO;` is
#       not more readable and explicit casts actively harm, as they mute
#       a lot of compiler diagnostics.
# - bugprone-assignment-in-if-condition:
#       This is idomatic C and not disallowed or discouraged by the coding
#       convention:
#       ```c
#       if ((err = something()) < 0) {
#            return err;
#       }
#       ```
#       So let's not warn about it, while it still is considered acceptable.
# - readability-isolate-declaration:
#       Multiple declaration in a single line is not disallowed by the coding
#       convention used a lot in the code base. So let's allow it.
# Warning
# -------
#
# This configuration file is rather new and may enable a few warnings with a
# low signal-to-noise ratio are may not enable checks that would be exteremely
# helpful. If you modify this file to improve your experience, please consider
# upstreaming the changes.
---
Checks: "bugprone-*,
         clang-analyzer-*,
         linuxkernel-*,
         misc-*,
         portability-*,
         readability-*,
         -bugprone-assignment-in-if-condition,
         -bugprone-easily-swappable-parameters,
         -bugprone-narrowing-conversions,
         -bugprone-reserved-identifier,
         -readability-identifier-length,
         -readability-implicit-bool-conversion,
         -readability-isolate-declaration,
         -readability-magic-numbers,
        "
WarningsAsErrors: "bugprone-*,
                   portability-*,
                  "
HeaderFilterRegex: ''
FormatStyle:     file
CheckOptions:
  readability-function-cognitive-complexity.IgnoreMacros: 'true'