VERSION option adds "v" prefix resulting in invalid tags about cpm.cmake

[iboB]

Technically we could make use of git ls-remote to query available tags and see whether they are in the form of "A.B.C" or "vA.B.C". However I think that something like this is too big and risky to do at this point. Perhaps it's a good idea for the (not-so-near) future

[lolleko]

nvm just found GIT_TAG param.

But to be honest the VERSION parameter is a bit confusing, what's the benefit of having an extra VERSION option instead of just GIT_TAG

[TheLartians]

Hey, I'm glad you solved it! In general, the GIT_TAG is for the git tag and the version is for specifying the (lexical) version number of the package, so CPM.cmake is able to emit a warning when a dependency asks for a more recent version of a dependency than currently used. As different packages will ask for different versions of a dependency, the idea is to have them available in a minimum required version.
As the tag and the version are often closely related we decided it would be convenient to have CPM.cmake set VERSION to <GIT_TAG>, or GIT_TAG to v<VERSION> if one or the other is not explicitly specified.

[Leon0402]

As this has been marked a duplicate of similar issues, I will answer in here:

I agree with your comments @TheLartians that prefixing with v is common (and recommend by GitHub). I do think that a version number without any v prefix is very common as well.
So to make life a little bit easier why not support both?

If this is something that could be implemented, maybe the issue should be reopened

[TheLartians]

@Leon0402 I agree, which is why the version is automatically inferred If only the GIT_TAG is provided in a suitable format. Also note the shorthand syntax, that supports an easy notation for providing only the tag.

# A git package from a given uri with a version
CPMAddPackage("uri@version")
# A git package from a given uri with a git tag or commit hash
CPMAddPackage("uri#tag")
# A git package with both version and tag provided
CPMAddPackage("uri@version#tag")

For example, the range-v3 can be fetched using simply CPMAddPackage("gh:ericniebler/range-v3#0.11.0") and CPM.cmake will infer the correct version from the tag.

[IronAttorney]

Is version able to be something other than a tag then? There are 3rd party repos without tags I wish to use in my current project where I am using CPM manager for all 3rd party package management for the first time.

EDIT:
Literally straight after sending this I thought to try #0 for the tagless repo and it worked! Nice touch