Add normalize_path into the cmake -E

Development
1

It would be very convenient, e.g., for some environments in which the mixed slashes could approach
I got this at GitHub Actions with their github.workflow - it has backslashes on Windows, but it was mixed with forward slashes and CMake has reported an error:

Run cmake -B build -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH="D:\a\std_version\std_version/build" -DCMAKE_MODULE_PATH="D:\a\std_version\std_version/build"
-- Building for: Visual Studio 17 2022
-- The CXX compiler identification is MSVC 19.34.31935.0
-- Detecting CXX compiler ABI info
CMake Error at D:/a/std_version/std_version/build/CMakeFiles/CMakeScratch/TryCompile-ej6is1/CMakeLists.txt:2 (set):
  Syntax error in cmake code at

    D:/a/std_version/std_version/build/CMakeFiles/CMakeScratch/TryCompile-ej6is1/CMakeLists.txt:2

  when parsing string

    D:\a\std_version\std_version/build

  Invalid character escape '\a'.


CMake Error at C:/Program Files/CMake/share/cmake-3.25/Modules/CMakeDetermineCompilerABI.cmake:57 (try_compile):
  Failed to configure test project build system.
Call Stack (most recent call first):
  C:/Program Files/CMake/share/cmake-3.25/Modules/CMakeTestCXXCompiler.cmake:26 (CMAKE_DETERMINE_COMPILER_ABI)
  CMakeLists.txt:4 (project)


-- Configuring incomplete, errors occurred!
See also "D:/a/std_version/std_version/build/CMakeFiles/CMakeOutput.log".

I’m thinking on making the simplest script with cmake_path() and executing it ad-hoc for normalizing paths, but the cmake -E normalize_path <path> would be more convenient. It looks like:

cmake_minimum_required(VERSION 3.20)
# cmake -P NormalizePath.cmake <path> - <path> is argv3
cmake_path(SET FS_PATH NORMALIZE "${CMAKE_ARGV3}")
message("${FS_PATH}")

and can be launched via cmake -P NormalizePath.cmake C:\some/wacky//weird/./path.

p.s. Github Actions run on Windows with failure logs: feat(CI): Test Github Actions on Windows and Macos (Take #2) · leha-bot/std_version@b12824b · GitHub

2

If you use -DCMAKE_PREFIX_PATH:PATH does it work (by telling CMake “this is a path” which then does /-normalization when inserting into the cache)? The problem here seems to be that the prefix path is written literally to the script where \ is an escape character. CMake generally prefers to use / in paths and convert to \ only where necessary.

1 Like
3

agreed, yes, and I think that instead of writing the script it’s better to call the proposed cmake -E normalize_path ${{github.workspace}}/build

4

The other thing CMake should do is escape variable values it writes for try_compile and friends.

Is there not a PowerShell command for doing this in the meantime?

5

That’s a bit of a lie, because formally CMAKE_PREFIX_PATH is a list of paths. That means STRING is the more correct variable type, since we have no other variable type for lists of anything. Quite often, a user might only put one path in CMAKE_PREFIX_PATH, which may make a PATH variable type appear to work. Maybe it’s fine when it only contains one value, but we shouldn’t really encourage this.

6

Ideally, we’d have PATHLIST or something, but CMake and types…

1 Like
7

I send a (maybe ad-hoc) fix for MODULE_PATH: https://gitlab.kitware.com/cmake/cmake/-/merge_requests/8012