Hi Thomas,

I'm afraid we're likely to remove the extraFlags extension that atom-ide-cpp is using: https://reviews.llvm.org/D53641

Clangd has grown lots of methods of customizing compile commands. They overlap and have subtle differences, and this is causing us some reasoning about how new features should behave.

I think there are a few good alternatives:

• compile_flags.txt is a fully-supported alternative to compile_commands.json for specifying compile commands for simple projects. It has exactly the same format as .clang_complete so renaming or symlinking this file will work for users.
• we have a protocol extension that allows the full compile command to be specified (currently only in a certain configuration, but soon always). The full compile command is just clang $FILENAME $EXTRA_FLAGS, or clang -xobjective-c++-header $FILENAME $EXTRA_FLAGS for *.h files. Happy to provide more details.
• we can add a protocol extension that allows the fallback command to be customized with extra flags.

Hopefully one of these will work well enough. You may need to respect both the old and new method for a while, because of version skew.

Happy to help out with migration if you like!

Cheers, Sam