Include What You Use #8357
Description
Include What You Use (no more, no less)
References:
- https://google.github.io/styleguide/cppguide.html#Include_What_You_Use
- https://rawgit.com/AliceO2Group/CodingGuidelines/master/coding_guidelines.html#Header_Files
- https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#sf10-avoid-dependencies-on-implicitly-included-names
- https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rs-contained
- https://llvm.org/docs/CodingStandards.html#include-as-little-as-possible
- https://github.com/include-what-you-use/include-what-you-use/blob/master/docs/WhyIWYU.md
Tools:
- https://clang.llvm.org/extra/clang-tidy/checks/misc/include-cleaner.html
- https://clang.llvm.org/extra/clang-tidy/checks/llvm/include-order.html
- https://clangd.llvm.org/design/include-cleaner
- https://clangd.llvm.org/guides/include-cleaner
- https://github.com/bkryza/clang-include-graph
Ideas:
- A file which does not include what it uses does not compile. This can be tested with:
(It should be enough to check for non-zero exit code to detect compilation errors.)
clang-tidy <file>
However, if it compiles, it does not mean that all used headers are included directly nor that no unused headers are included. - When the file compiles, the includes in it can be fixed automatically with:
until there are no warnings left.
clang-tidy --fix -checks=-*,misc-include-cleaner <file>
- Once all headers are self-contained, source files can be fixed with the same procedure.