config of package_id default mode

[memsharded]

Changelog: Feature: Allow configuring in conan.conf a different default package_id mode.
Docs: conan-io/docs#1106

Close #4071

[jgsogo]

This one is targeting (and closing) #4071, isn't it?

[lasote]

Should the value be None or semver? Why not present in the conan.conf? I would like to see default_package_id_mode=semver explicit, always. In case someone doesn't have it, return "semver" instead of None

[lasote]

The values shouldn't contain the "_mode" suffix.

[danimtb]

I would like to see the possible values as comments in the conan.conf too. I even like the idea of having a link to the docs section if we feel this feature is important enough...

[memsharded]

It is different to not define a new default_package_id_mode, than defining it to semver. This is the logic:

# sha values
        if package_id_mode:
            try:
                getattr(self, package_id_mode)()
            except AttributeError:
                raise ConanException("'%s' is not a known package_id_mode" % package_id_mode)
        else:
            if indirect:
                self.unrelated_mode()
            else:
                self.semver_mode()

So if defaults to semver it will never apply the current unrelated_mode() that is applying to indirect (transitive, but not declared) dependencies, changing the current behavior.

Maybe we need to discuss this, but I thought that the new default mode would apply to all dependencies, transitive indirect dependencies too.

[danimtb]

I really fail to see the whole picture now, so I will need a brief explanation

[lasote]

I think package_id_mode shouldn't be optional.

[jgsogo]

A comment about naming: I think it should resemble the naming we already have documented: semver_mode, major_mode,... so the suffix might be redundant, but I think it should be there.

[lasote]

One thing is the mode in the config, and a different one is the helpers in the package_id.
In the config default_package_id_mode=semver_mode is redundant

[jgsogo]

Totally redundant, but the user will search for semver_mode (or any other mode) and will find the documentation about the default_package_id_mode in the conan.conf and the docs about the ABI compatibility definition (I also think that maybe the name should be default_abi_compatibility instead of default_package_id_mode)

I'm just commenting these things in case you haven't realized about them; naming is hard, keeping the docs updated too, linking one section of the docs with other sections is also important. I think that having the same naming for the strings that the user has to manage is better, I'm not saying anything about the naming of the variables. But let's ping @danimtb, as the guardian of the docs his opinion about naming is important too.

[danimtb]

Although it may be redundant, I think it is better to keep the same naming as in that section. Users are not very used to this kind of use cases and I think the section is well documented, so having to explain the modes twice is not necessary.

I am not sure about the default_abi_compatibility name, as there might be options not necessarily affecting the ABI like having a package with tests or stuff like that

[lasote]

Totally opposed to default_abi_compatibility

[lasote]

Pending create and document a new mode describing the default behavior and introduce it as the default, visible, in the conan.conf and return it instead of the None

[lasote]

Conficts!