In addition to the well-known
-Wall, clang offers another interesting warning flag:
-Weverything. While it sounds like a “strictly better” option (the more warnings, the better?) it’s not.
This topic is already well covered by Arthur O’Dwyer’s blog post and the clang documentation.
Arthur makes a strong case against use of this flag. The clang docs generally agree, though offering a slightly more lenient position:
If you do use
-Weverything then we advise that you address all new compiler diagnostics as they get added to Clang, either by fixing everything they find or explicitly disabling that diagnostic with its corresponding Wno- option.
But what I have not seen clearly expressed is how use of
-Weverything is a tradeoff.
If you’re already a 10x engineer, you probably won’t need this article. But for the rest of us, this is what I wish I knew about clang-format as an inexperienced C++ programmer: how to only format the changes in your pull request.
You may have already heard of clang-format. It auto-formats source files for languages including C and C++. You can aim it at a source file and format the entire thing using
clang-format -i file.cpp.
If you’re contributing to a project that is already 100% clang-format clean, then this workflow works fine. But you’ll occasionally encounter a project that is not quite 100% formatted, such as LLVM, osquery, or Electron.
For these projects, the “format entire files” workflow doesn’t work because you’ll incidentally format parts of the files that are unrelated to your contribution. This will add noise to your diff and make it harder for your reviewers.
In this case, you need a way to surgically format only the lines changed in your contribution. To do this, you can use the clang-format git extension. This article will cover the basics of git-clang-format, including a practical workflow that allows for messy development, and formatting at the end.