Issue with `find_package(beman::transform_view REQUIRED)`

[elvisdukaj]

Describe the deficiency

I am trying to create the conan packages for the beman project as in this thread. But Conan doesn't support creating CMake configuration containing semicolons like find_package(beman::transform_view REQUIRED) and I am pretty sure this is illegan on Windows (but I cannot confirm since I don't have any Windows machine to test).

Additional Discussions

Are we sure we want to create filenames containing "::"?

[ednolan]

I think maybe we can use the double semicolons for the CMake targets but use dots for the package names-- I bet in this case find_package(beman::transform_view REQUIRED) should have just been spelled find_package(beman.transform_view REQUIRED)

[ClausKlein]

How should this work?

bash-5.3$ tree ~/.local/lib/cmake/beman.transform_view/
/Users/clausklein/.local/lib/cmake/beman.transform_view/
├── beman.transform_view-config-version.cmake
├── beman.transform_view-config.cmake
├── beman.transform_view-targets-release.cmake
├── beman.transform_view-targets.cmake

[elvisdukaj]

@ClausKlein that's correct. We shouldn't create:

/Users/clausklein/.local/lib/cmake/beman.transform_view/
├── beman::transform_view-config-version.cmake
├── beman::transform_view-config.cmake
├── beman::transform_view-targets-release.cmake
├── beman::transform_view-targets.cmake

as filenames.

[ClausKlein]

No!

there are naming restrictions and conventions:

• https://cps-org.github.io/cps/configurations.html#configuration-merging
• https://cmake.org/cmake/help/latest/command/find_package.html#search-procedure
• A filename on windows cannot contain any of the following characters: \ / : * ? " < > |

CMake Error at infra/cmake/beman-install-library.cmake:264 (install):
  install EXPORT given export name "beman::transform_view-targets".  This
  name cannot be safely converted to a file name.  Specify a different export
  name or use the FILE option to set a file name explicitly.
Call Stack (most recent call first):
  CMakeLists.txt:80 (beman_install_library)

[elvisdukaj]

I am a bit confused on how is possible this works though... looking the transform_view repo I see the correct name. So it should be a simple typo.

In the conan package I am trying to create see thread I have added a patch this and everything works as expected.

I will submit a PR shortly.

[ClausKlein]

But :: is not portable in filenames (especially on Windows, where : is illegal), so CMake refuses.

Recommended cmake package names:

package-name: [A-Za-z0-9_]+
namespace: package::
targets: package::component

Identifier	Allowed chars
Package name	[A-Za-z0-9_]+
Target name	[A-Za-z0-9_]+(::[A-Za-z0-9_]+)*
Export/file names	filesystem-safe (avoid :)

[elvisdukaj]

@ClausKlein maybe there is a misunderstanding? This is a bug.

When you say

find_package(beman::transform_view REQUIRED)

find_package is expecting to find a filename that is (for config):

beman::transform_view-config.cmake
beman::transform_viewConfig.cmake
beman::transform_view.cps

This is not what I am suggesting and it should be changed to:

find_package(beman.transform_view REQUIRED)