Several people (including me) seem to expect git-describe's commit count to be calculated differently than how it's actually calculated. For example, see the following three Stack Overflow questions:
http://stackoverflow.com/questions/31852885/git-describe-inexplicable-commit-count http://stackoverflow.com/questions/33116182/can-i-change-how-git-describe-counts-commits http://stackoverflow.com/questions/13568372/commit-count-calculation-in-git-describe
The scenario that all three questions is asking about is the following:
1) I'm working along on a branch whose most recent tag is v1.1, created 96 commits ago. 2) Someone else merges some work into master, and tags with v1.2. I want to incorporate their work into my own, so I merge master into my branch. 3) I now have a branch that is one commit "forward" from tag v1.2. I therefore expect git-describe to say "v1.2-1-g1234567". Instead, I get "v1.2-97-g1234567".
Now, git-describe is working precisely as documented here. The documentation describes the commit count as being "the number of commits which would be displayed by 'git log (tag commit)..(described commit)' " and that is indeed what I'm getting. If I do "git log v1.2..HEAD", there will be 97 log entries, because the latest commit that is an ancestor of both v1.2 and HEAD is where my branch was created from master 97 commits ago.
However, this is unexpected behavior for me. I was expecting to get a commit count of 1, not a commit count of 97. Instead of a count of all the commits since I forked from master 97 commits ago, I was expecting a count of all the commits since the tag that git-describe has picked as the latest tag. In other words, instead of the count to match "git log v1.2..HEAD", I was expecting the count to match "git log --ancestry-path v1.2..HEAD".
As shown by the Stack Overflow questions above (one of which is mine), I am not alone in finding this behavior to be surprising. I would like to request that git-describe acquire an additional option, "--ancestry-path", to use the same method as "git log --ancestry-path" to count commits. I would prefer that this become the default, but I realize that that might be a breaking change (some people might have build scripts that relied on git-describe's current behavior).
This is either a bug report or a feature request, depending on how intended the current commit-count behavior is.
I've reproduced this behavior on both older versions of git (1.9.1) and recent versions (2.6.2).
-- Robin Munn Robin.Munn@gmail.com GPG key 0x4543D577
