Compute CMAKE_PROGRAM_PATH from returned json

[jcar87]

This might work to set this after the first call to find_package (as the known limitation).

The implementation in CMakeToolchain is:

        build_req = self._conanfile.dependencies.build.values()
        build_bin_paths = []
        for req in build_req:
            cppinfo = req.cpp_info.aggregated_components()
            build_paths.extend(cppinfo.builddirs)
            build_bin_paths.extend(cppinfo.bindirs)

This is just an approximation by relying on the json alone.

[memsharded]

I think it is fine, can be moved forward.
Maybe we want to consider at some point having something built-in, a new generator or something that can just generate the information in a way that it can be consumed more easily by the provider?

[memsharded]

Maybe it would be a bit cleaner to do a function and "return" the variable to be used later

[memsharded]

"Downloaded" or "Updated" will also be available to use, why ignoring them?

[jcar87]

Oh I see! Yeah I need to add those - the ones that have "skip" still have the fields but they are null, so I need a way to filter out anything that isn't valid. Perhaps this isn't the best field to check if the binary package is in the cache (I'm assuming that Cache, Download and Updated for the binary field ALL mean they are in the cache with valid paths?)

[memsharded]

Isn't it enough to filter out the ones with binary=="Skip"? that should work I think.

[jcar87]

mmm what would happen if we have different versions of the same dependency (via tool requires), and tools.graph:skip_binaries=False ? would there be a chance that we add bin dirs for different versions of the samae dependency in this case?

[memsharded]

You can check the node context attribute, it will be "host" and "build", you can differentiate it.

[jcar87]

Can go with the condition "binary is not skip" and "context is build" - hopefully that covers all cases correctly!

[memsharded]

I think so

[memsharded]

Master of CMake! I am happy that I didn't have to write this code😄

[rturrado]

Wouldn't you play safer doing a comparison against a lowercase value?:

if(_dep_binary_lowercase STREQUAL "skip" OR NOT _dep_context_lowercase STREQUAL "build")

[rturrado]

Or even defining those "Skip", "build"... somewhere as constants. Although that may be overkill. 😄 This type of code always looks to me like a bit like "magic numbers".

[jcar87]

this part of Conan's json formatter, so it's essentially a public API - if this ever changed in Conan, our tests (in Conan) would fail straight away so we would know that would be a breaking change (minimising the chance of this ever happening - so not sure we can something by doing lowercase).

they could be constants but then we would have more indirection given how CMake expands variables but I'll consider that

[rturrado]

Thanks for the explanation! And roger that CMake code is by itself complicated enough to introduce further indirections.