CMT Tags
For what concerns the format of tags recognized by CMT, it appears that it is a lot more liberal that what one generally thinks. Actually, CMT only considers the numbers in the tag names. It is up to the collaboration to choose one format or the other. The only advice is to avoid dots, if the CMT is used together with CVS, because CVS will not like dots in the tag names.
The format which is generally used in the CMT documentation can be expressed thanks to this perl expression : v[0-9]+(r[0-9]+(p[0-9]+)?)?. Yet, only the numbers are really meaningfull to CMT, and we do not know to what extent the tag v3p1 could be considered equivalent to v3r1, or even to MyPackage-v3p1. I suspect it is not fully consistent, as seen in some bugs, and it must be investigated.
Release Manager LATEST
The Release Manager is filtering out all the tags which do not match v[0-9]+(r[0-9]+(p[0-9]+)?)?. This is a way not to take into account the tags which are applied on CVS branches, provided the developers do not use this format of tags on the branches !
Release Manager HEAD
The tags which are used in a HEAD build are explicitly defined one by one, under the controll of Navid. I guess the same rules as LATEST apply, but perhaps it is possible, for specific cases, that branches tas will be used.
Branch Tags and Tags on Branchs
I suspect there is a confusion, at least in my head, between the tags which are defining a branch, and the tags which are applied to some revision which is on a branch. I will try to distinguish between the former, which I will call "branch tags", and the latter, which I will call "tags on branches".
In some place related to the Release Manager, it is said that the tags v*r*p* should not be used on branches, and that the Release Manager is filtering out whatever tag is not v*r*p*, so to avoid branch tags. It is unclear if we mean branch tags, or tags on branches, or both.
On the other hand, sometimes we prepare a GlastRelease v*r*p*, with the p* which means one of the constituent package is branched. And the release manager HEAD is expected to be a preparation for this new GlastRelease v*r*p*, and the release manager LATEST is expected to be a preparation for HEAD... so it is expected that some tags on branches will be used in LATEST, then in HEAD, then for GlastRelease v*r*p*.
Places where there is information about tags
About CVS branches.
About Release Manager.
Within CMT introduction, when clicking on "Tagging Conventions".