fix: more readable error on missing `ccmake`

[Andrej730]

I've stumbled upon the error below, trying to use ccmake. Adding a bit more readable error for this case.

uv tool install cmake
# Installed 4 executables: ccmake, cmake, cpack, ctest
ccmake --version 
# Traceback (most recent call last):
#   File "<frozen runpy>", line 198, in _run_module_as_main
#   File "<frozen runpy>", line 88, in _run_code
#   File "C:\Users\Andrej\.local\bin\ccmake.exe\__main__.py", line 10, in <module>
#     sys.exit(ccmake())
#              ~~~~~~^^
#   File "L:\UV_TOOL_DIR\cmake\Lib\site-packages\cmake\__init__.py", line 53, in ccmake
#     _program_exit('ccmake', *sys.argv[1:])
#     ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^
#   File "L:\UV_TOOL_DIR\cmake\Lib\site-packages\cmake\__init__.py", line 47, in _program_exit
#     raise SystemExit(_program(name, args))
#                      ~~~~~~~~^^^^^^^^^^^^
#   File "L:\UV_TOOL_DIR\cmake\Lib\site-packages\cmake\__init__.py", line 43, in _program
#     return subprocess.call([os.path.join(CMAKE_BIN_DIR, name), *args], close_fds=False)
#            ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
#   File "L:\UV_PYTHON_INSTALL_DIR\cpython-3.14.0-windows-x86_64-none\Lib\subprocess.py", line 395, in call
#     with Popen(*popenargs, **kwargs) as p:
#          ~~~~~^^^^^^^^^^^^^^^^^^^^^^
#   File "L:\UV_PYTHON_INSTALL_DIR\cpython-3.14.0-windows-x86_64-none\Lib\subprocess.py", line 1038, in __init__
#     self._execute_child(args, executable, preexec_fn, close_fds,
#     ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
#                         pass_fds, cwd, env,
#                         ^^^^^^^^^^^^^^^^^^^
#     ...<5 lines>...
#                         gid, gids, uid, umask,
#                         ^^^^^^^^^^^^^^^^^^^^^^
#                         start_new_session, process_group)
#                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
#   File "L:\UV_PYTHON_INSTALL_DIR\cpython-3.14.0-windows-x86_64-none\Lib\subprocess.py", line 1552, in _execute_child
#     hp, ht, pid, tid = _winapi.CreateProcess(executable, args,
#                        ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^
#                              # no special security
#                              ^^^^^^^^^^^^^^^^^^^^^
#     ...<4 lines>...
#                              cwd,
#                              ^^^^
#                              startupinfo)
#                              ^^^^^^^^^^^^
# FileNotFoundError: [WinError 2] The system cannot find the file specified

[henryiii]

If you ran cmake --version, why is it looking for ccmake? Also, according to the line above, it did install ccmake. (No issue with better error messages, but might be something fixable?)

[Andrej730]

If you ran cmake --version, why is it looking for ccmake?

cmake --version was a mistake when typing example above, I meant ccmake --version, fixed.

Also, according to the line above, it did install ccmake. (No issue with better error messages, but might be something fixable?)

It did installed ccmake meaning ccmake.exe script as in project.scripts:

https://github.com/scikit-build/cmake-python-distributions/blob/40acf75985b28bd112b28ddc4506f5e0283cbd45/pyproject.toml#L38-L42

But the way this script works, it imports cmake module and executes corresponding ccmake method below:

https://github.com/scikit-build/cmake-python-distributions/blob/ecad19912918f6975d32491a60812ce78eb9e33e/src/cmake/init.py#L52-L55

And ccmake.exe is not included in the package (at least on Windows) as probably part of https://github.com/scikit-build/cmake-python-distributions/issues/66 and also there are issues upstream (https://gitlab.kitware.com/cmake/cmake/-/issues/18053).

[henryiii]

Ahh, excellent, thank you. We could make the entry points dynamic, but that would be nicer if PEP 808 is accepted. I had missed it isn't in the official distribution, which we use.

[Andrej730]

Removing/adding entry point dynamically would be more proper solution, but I'm not familar with scikit build backend, so I'd rather keep this PR as just a clarified error message.