On 2014-08-22 09:45-0400 Hazen Babcock wrote: > On 8/21/2014 8:48 PM, Alan W. Irwin wrote: >> So we were all in agreement that storage (in a file) of the SHA1 id of >> the HEAD commits from each branch to be deleted would be enough to >> guarantee branch resurrection, but it turns out that is incorrect. >> Further reading shows that git automatically garbage collects >> (deletes) all "unreachable" commits after a suitable default period >> (usually 90 days, I think). So there are lots of warnings in the >> results for google searching for the terms <git resurrect branch> that >> the techniques only work for a while until garbage collection occurs. > > Hm, that is my take on this as well. I agree that if we want to preserve the > branches then we'll need to tag them. Buried in the comments to the first > answer to this question is an explanation of how to push the tags to the > remote repository: > > http://stackoverflow.com/questions/2342821/git-branch-deletion
Thank goodness for stackoverflow. What a great response that deals with essentially all questions we have had about this issue. > > If you are really worried about history preservation then you should also > implement a server side hook to prevent tag deletion. I think it is an excellent idea to do everything we can to preserve our development history. Accordingly, I have now modified the update hook appropriately and put it under git control (see latest push of ffada3a). I have tested that logic with a "play" bare server repo and a local working directory repo that uses the bare one as a remote. For that case, git push --tags works for propagating new local tags to the official repo (consistent with the stackoverflow answer). And it nicely errors out if you attempt to reuse an old tag for a different commit. i.e., git tag -f <oldtagname> <newcommit ID> git push --tags However, "git push --tags" completely ignores locally deleted tags (one of a number of arcane things about git that are difficult to understand). In order to attempt to propagate tag deletes to the server you need to run instead the alternative syntax git push --delete origin <tagname> The current update hook obligingly errors out in that case as well. So all seems well with its logic, but by all means try it yourself for your own play repos. I have just now propagated this new version to the correct part of the SF repo using the following two commands. ssh airwin,plp...@shell.sourceforge.net create (wait for a few minutes until it responds with the message that your shell access is ready to go [for the next 4 hours]). software@raven> scp \ /home/software/plplot_svn/HEAD/plplot.git/git_hooks/update \ airwin,plp...@shell.sourceforge.net:/home/git/p/plplot/plplot.git/hooks If anything screws up with that update logic, i.e., any of us are getting error messages from attempting to make a legit push that include no invalid tag deletes, tag reuses, or merge commits, then one of us will need to adjust the logic in git_hooks/update, push it so others can see the change that has been made, and do the equivalent two commands above to deploy/activate it. If you have time, and now that I have made it impossible for tags to be deleted/reused for our SF repo, then I would appreciate you following up by taking responsibility for the safe branch deletion of all the svn-generated branches other than master. Alan __________________________ Alan W. Irwin Astronomical research affiliation with Department of Physics and Astronomy, University of Victoria (astrowww.phys.uvic.ca). Programming affiliations with the FreeEOS equation-of-state implementation for stellar interiors (freeeos.sf.net); the Time Ephemerides project (timeephem.sf.net); PLplot scientific plotting software package (plplot.sf.net); the libLASi project (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net); and the Linux Brochure Project (lbproject.sf.net). __________________________ Linux-powered Science __________________________ ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that matters. http://tv.slashdot.org/ _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
