问题1：找不到cregex

从这里clone regex 然后安装

问题2：regex does not appear to contain CMakelist.txt

[100%] Linking CXX shared library /root/kvim/k-vim/bundle/YouCompleteMe/third_party/ycmd/ycm_core.so
[100%] Built target ycm_core
CMake Error: The source directory "/root/kvim/k-vim/bundle/YouCompleteMe/third_party/ycmd/third_party/cregex" does not appear to contain CMakeLists.txt.
Specify --help for usage, or press the help button on the CMake GUI.
ERROR: the build failed.

NOTE: it is *highly* unlikely that this is a bug but rather
that this is a problem with the configuration of your system
or a missing dependency. Please carefully read CONTRIBUTING.md
and if you're sure that it is a bug, please raise an issue on the
issue tracker, including the entire output of this script
and the invocation line used to run it.

所以上面的regex clone 下来以后，记得改名为cregex….

cd third_party
mv regex cregex
cd ..
python3 install.py -all

…..wait….这货是瞎了吗？仍然看不到cregex的CMakeList.txt?

# 给你们看看智障行为
实际上cregex的位置在于YCM/third_party/ycmd/third_party内而不是YCM/third_party内，于是出现了上面那样的错误。。

cd YouCompleteMe
git submodule sync --recursive
git submodule update --init --recursive
cd ./third_party/ycmd/third_party/
git clone https://github.com/ycm-core/regex.git
cd ..
cd ..
cd ..
python3 ./install.py

这样应该就可以了

参考

官方readme.md
regex
issue 3232
issue 3476
cregex did not contain cc538bb6d0fcf0a6411537a5522d13cc9b86789d #3479