Intermodule dependency on -SNAPSHOT qualifier conflicts with BinaryAndSourceCompatibility setting

[seigert]

We have a project with two modules: api, client.dependsOn(api). They share same version setting: ThisBuild / version := "1.2.1-SNAPSHOT".

If we use BinaryAndSourceCompatible compatibility settings we get following error on versionPolicyCheck:

[error] Incompatibilities with dependencies of client:1.2.0
[error]   api_2.13: incompatible version change from 1.2.0 to 1.2.1-SNAPSHOT (compatibility: strict semantic versioning)
[info] Module api:1.2.1-SNAPSHOT has no dependency issues with version 1.2.0 (versionPolicyIntention is set to 'Compatibility.BinaryAndSourceCompatible')
[info] Module client:1.2.1-SNAPSHOT is binary and source compatible with version 1.2.0

Setting either version to 1.2.1, compatibility to BinaryCompatible or adding versions with qualifier to versionPolicyIgnoredInternalDependencyVersions resolves this error.

What is strange to me is that version of client in error above is 1.2.0, i.e. taken from previous artefacts.

[julienrf]

versionPolicyCheck checks that the dependencies of the current version of the module client don’t break the compatibility guarantees (as per versionPolicyIntention) with respect to the dependencies of the previous version of the module client, which in your case is the version 1.2.0. Hence the message “Incompatibilities with dependencies of client:1.2.0”. The reported incompatibility is that the dependency to the module api changed from version 1.2.0 to version 1.2.1-SNAPSHOT, and sbt-version-policy does not know how to compare a stable version number with a pre-release version number. That’s why changing the version to 1.2.1 does work.

Changing the compatibility intention to BinaryCompatible works because the check is slightly different: we delegate to Coursier, whose algorithm seems to support the -SNAPSHOT suffix. I am tempted to say that we should probably align both behaviors (with BinaryCompatible and BinaryAndSourceCompatible), and probably it makes sense to just ignore the -SNAPSHOT part (or any pre-release identifier or metadata part). We could achieve this by adapting the code here to not require exactly 3 items, but at least 3 items. We would also have to update the test cases here.

What do you think?

[seigert]

Sorry for the long wait, I'm in full agreement with your proposed changes. I'll try to find time to implement it.