Retain old versions on update site (to allow reverting)

[schulmar]

After a broken update of Eclipse I tried to revert to a previous state (Help->Installation Details->Installation History) to regain a working version.

However, that older version also had an older version of CppStyle which is not available anymore on the update site.

Eclipse aborted reverting with the error message

An error occurred while collecting items to be installed
session context was:(profile=epp.package.cpp, phase=org.eclipse.equinox.internal.p2.engine.phases.Collect, operand=, action=).
No repository found containing: org.eclipse.update.feature,org.wangzw.cppstyle.feature,1.2.4.0

Being unable to revert CppStyle prevents the whole revert from taking place (although I could work with the newer version of CppStyle).

Please retain the older versions of CppStyle on the update site to allow for reverting.

[wangzw]

I do not think I can keep the old version because some file's name in update site does not contain the version number. So I guess it is impossible to revert to a old version using the same update site URL.

One solution is to create release branch or tag and use unique update site URL and never change its content any more.

Eg., release cppstyle for mars on version 2.0 with update site http://www.cppstyle.com/mars-v2.0. If the users want to revert to version v1.0, they have to modify the update site URL to v1.0.

What's your opinion?

[schulmar]

I do not think I can keep the old version because some file's name in update site does not contain the version number.

Which files do you mean?

When exporting an update site from Eclipse it automatically merges the previous one and the new contents and registers the new files in content.jar (and the other files as well, I believe). Maybe something similar is possible with your build system?

One solution is to create release branch or tag and use unique update site URL and never change its content any more.

Setting up each version in its own folder sounds error prone so I would not do that.

Meanwhile, I was able to do the revert by checking out the gh-pages commit for this version locally and adding it as another source in Eclipse's Install New Software dialog.