[question] Is it possible to model the glibc forward compatibility?

[leha-bot]

What is your question?

I had added the glibc.version (as was suggested in #3972 (comment) )
and I'm stuck with the issue: how could I mark the packages as compatible with any libc.version greater or equal current.

Example:

1. I created and exported the package on old Ubuntu with libc_version, for example, 2.28
2. I want to consume this binary package on new Ubuntu with libc_version 2.32
3. What should I do with conanfile.py? I thought also about compatibility.py, but don't understand, is it suitable for this

According to https://docs.conan.io/2/reference/conanfile/methods/compatibility.html , I should check the current libc.version with some prebuilt version, if I understood correctly, but how can I get it from first step?

Sorry for potentially vague question, feel free to ask, if I wrote something weird.

Have you read the CONTRIBUTING guide?

• I've read the CONTRIBUTING guide

[AbrilRBS]

Hi @leha-bot thanks a lot for your question.
You're right in assuming that the best approach for your request would be to use the compatibility.py extension.
A very basic one would look something like this:

<conan_home>/extensions/plugins/compatibility/compatibility.py

from glibc_compat import glibc_compat
def compatibility(conanfile):
    configs = cppstd_compat(conanfile)
    # TODO: Append more configurations for your custom compatibility rules
	libc_versions = glibc_compat(conanfile)
    # This is where you would need to do extra work for the crossproduct of cppstd and libc compats
    # For now it just adds them
    configs.extend(libc_versions)
    return configs

And your <conan_home>/extensions/plugins/compatibility/glibc_compat.py file:

from conan.tools.scm import Version

def glibc_compat(conanfile):
    # Do we have the setting?
    libc_version = conanfile.settings.get_safe("libc_version")
    if libc_version is None:
        return []
    available_libc_versions = conanfile.settings.libc_version.possible_values()
    ret = []
    for possible_libc_version in available_libc_versions:
        if Version(possible_libc_version) >= Version(libc_version):
            ret.append({"settings": [("libc_version", possible_libc_version)]})
    return ret

Some notes:

• As written, this would not create the cross product of cppstd compatibility and glibc versions. If that's desired, the logic would need to be a bit different
• These compatibility changes should at the very least be part of the consumer config, which is the one that needs to be able to iterate them

Additionally, I've submitted a test in #17524 to reflect this suggestion and ensure we can use it as a reference point in the future

Let me know if this helps :)

[leha-bot]

Big thanks, it worked when I swapped the version comparison sign here:

 if Version(possible_libc_version) >= Version(libc_version):

I also used the dotted values for glibc version in settings_user.yml ("os.libc.version")
settings_user.yml.zip

Debug log for conan install --requires=fmt/11.0.0

======== Computing necessary packages ========
2.39
['2.0', '2.1', '2.2', '2.3', '2.4', '2.5', '2.6', '2.7', '2.8', '2.9', '2.10', '2.11', '2.12', '2.13', '2.14', '2.15', '2.16', '2.17', '2.18', '2.19', '2.20', '2.21', '2.22', '2.23', '2.24', '2.25', '2.26', '2.27', '2.28', '2.29', '2.30', '2.31', '2.32', '2.33', '2.34', '2.35', '2.36', '2.37', '2.38', '2.39']
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
2.10
2.11
2.12
2.13
2.14
2.15
2.16
2.17
2.18
2.19
2.20
2.21
2.22
2.23
2.24
2.25
2.26
2.27
2.28
2.29
2.30
2.31
2.32
2.33
2.34
2.35
2.36
2.37
2.38
2.39
fmt/11.0.0: Main binary package 'eafad8a7125e3266294c4a2cbe8f3373e6e2a785' missing
fmt/11.0.0: Checking 39 compatible configurations
fmt/11.0.0: Compatible configurations not found in cache, checking servers
fmt/11.0.0: '8f79c18cf917dd784543b0a7e7c41ada73225d54': os.libc.version=2.0
fmt/11.0.0: '295bb19a67909d5ff78ce348e7307ab8c2dbb0a3': os.libc.version=2.1
fmt/11.0.0: 'ab8c16cf32ed0d3dbc48f34e7439300a63f33ecc': os.libc.version=2.2
fmt/11.0.0: '197894ef1620f7945cfa9e0a3892c0bef55918e9':
fmt/11.0.0: 'ee19daa8c26f3836cd2e0eddd14a6d28b2653894': os.libc.version=2.4
fmt/11.0.0: 'aa4fb8da1c40531930e7e2560f55b5b57fb94d8f': os.libc.version=2.5
fmt/11.0.0: '17049a7dbd880274920911da527e702ff84b0032': os.libc.version=2.6
fmt/11.0.0: '6e2fd6901f3798beb01d2a8252bacbb7af04dc61': os.libc.version=2.7
fmt/11.0.0: '04469fe5ea0fc0ea650c8a9044be4f080022da5b': os.libc.version=2.8
fmt/11.0.0: '1efd15f72dec684ce6de6a3670fa73990395eb7e': os.libc.version=2.9
fmt/11.0.0: '500b7c8acbafeb17f541644bf543cf57b60ffb21': os.libc.version=2.10
fmt/11.0.0: '48c859127659dc43a04d2220cc03951bde1ee8cc': os.libc.version=2.11
fmt/11.0.0: '20cae635e9a4b925fde97c7a998e37aa39f05275': os.libc.version=2.12
fmt/11.0.0: '9952ff15cdc47857f6f752bfc3a11f0f1888f0ea': os.libc.version=2.13
fmt/11.0.0: 'bda3feba48a2bfcd2d4dafaed4265007e9c8fd26': os.libc.version=2.14
fmt/11.0.0: '9ef70e0bf9b6e15da206bb8e4105335aa217309a': os.libc.version=2.15
fmt/11.0.0: '87b106f214355ced9fb469bacab4862784a4b8c0': os.libc.version=2.16
fmt/11.0.0: 'd68ac9253db925c052536e668647b3b7b671b936': os.libc.version=2.17
fmt/11.0.0: 'ebd101d774103fee5128525d766832db2b12aa64': os.libc.version=2.18
fmt/11.0.0: '4ea2026a50f32fc5c182d6eaa472f501eb1ee5fa': os.libc.version=2.19
fmt/11.0.0: '4b74a93ada7aeb624d10beed73bbee4e4fb5d06f': os.libc.version=2.20
fmt/11.0.0: '8824541ff4e9d2c979b84470bbfa63fa69c073fe': os.libc.version=2.21
fmt/11.0.0: 'd8505431fe685055a57efddfaa77b9f2deac08f0': os.libc.version=2.22
fmt/11.0.0: '2d8387c59349860f616112a652a887a43fdefa5c': os.libc.version=2.23
fmt/11.0.0: '4819c09b7c4dc32791e7ffc9e68aa6beae2b4ecf': os.libc.version=2.24
fmt/11.0.0: 'b86b59718eb1f9a1fee2538f1fcfd79862ff407b': os.libc.version=2.25
fmt/11.0.0: '24c57359afc36fd7b790ee19851971816b8ded5d': os.libc.version=2.26
fmt/11.0.0: 'da33e20a24981ae51424b46d1275a90a9a2fae4f': os.libc.version=2.27
fmt/11.0.0: 'fdf59b56ddc917d493fbbc210e09530192512e83': os.libc.version=2.28
fmt/11.0.0: '160f1b278b20b10d4ab03eb9e2a321338192173c': os.libc.version=2.29
fmt/11.0.0: '1196af7c0add5cdd7144c221db0e961dadf7e98c': os.libc.version=2.30
fmt/11.0.0: '59a2d2c125872977cab4a55b5c5dc1b13f1350a8': os.libc.version=2.31
fmt/11.0.0: '8030d72e4e65dad348029ca491505ec7f4d4573c': os.libc.version=2.32
fmt/11.0.0: '353b1693573d9ee22978676459092338a39f37c4': os.libc.version=2.33
fmt/11.0.0: '8ccce8eda2efdc9516f7e48d79721d4b85c193a0': os.libc.version=2.34
fmt/11.0.0: '584fe6b02beb7608f6eb5766037061e3d640558d': os.libc.version=2.35
fmt/11.0.0: Found compatible package '584fe6b02beb7608f6eb5766037061e3d640558d': os.libc.version=2.35