Re: VCS comparison table

Dnia wtorek 17. października 2006 23:01, Jakub Narebski napisał:

Aaron Bentley wrote:

quoted

Andreas Ericsson wrote:

quoted

Aaron Bentley wrote:

quoted

Ah.  Bazaar uses negative numbers to refer to <n>th parents, and
positive numbers to refer to the number of commits that have been made
since the branch was initialized.

What do you do once a branch has been thrown away, or has had 20 other
branches merged into it? Does the offset-number change for the revision
then, or do you track branch-points explicitly?

We always track the number of parents since the initial commit in the
project.  Sorry, I don't think I said that clearly before.

While this I think is quite reliable (there was idea to store "generation
number" with each commit, e.g. using not implemented "note" header, or
commit-id to generation number "database" as a better heuristic than
timestamp for revision ordering in git-rev-list output), and probably
independent on repository (it is global property of commit history,
and commit history is included in sha1 of its parents), numbering branching
points is unreliable, as is relying on branch names.

Take for example the following situation:


In the following we had

  A--B--C--D  - repository A

we have cloned repository

  A--B--C--D  - repository B

Then, in parallel/independently we branched off C in repository A, and
branched off B in repository B

          -x
         /
  A--B--C--D  - repository A


  A--B--C--D  - repository B
      \
       -y

If we then fetch changes from B into A, and fetch changes from A into B,
we will have that in repository A branch off C appeared earlier, and
in repository B branch off C appeared later.
-- 
Jakub Narebski
Poland