Chris Withers wrote at 2009-3-27 16:02 -0500: > ... >> Got zope.principalregistry 3.7.0. >> While: >> Installing zopetest. >> Error: There is a version conflict. >> We already have: zope.component 3.5.1 >> but zope.app.security 3.7.0 requires 'zope.component>=3.6.0'. > >Okay, so I thought I'd be smart and try the following buildout.cfg: > ... >What the hell is zope.app.security 3.7.0 doing being dragged down? >Is this a buildout snafu? Jim?
I fear we will have to learn to live with version conflicts until we are ready to pin each and every version used, either in the buildout itself or via a KGS (Known Good Set index). If we let "buildout/setuptools" decide which version to use, there is a good chance that it gets it wrong. The problem would be far smaller if "setuptools" (yes, this is the major component to blame in this case, not "buildout") would first construct the complete dependency graph and then try to search a global solution. Unfortunately, "setuptools" resolves dependancies incrementally (not globally): when it has to handle a dependency, it tries to find a distribution satisfying the requirements taking into account the distributions it already has -- but not the dependency requirements it will also have to satisfy in a short time. This way, it may take a distribution that after a short while will conflict with another dependancy requirement. Your observation above might (other chains are possible) result from: Some dependency specifies: "zope.component==3.5.1". Later some dependancy specifies: "zope.app.security" "setuptools" looks what distribution it can choose. Lacking a more specific prescription, it uses the newest one "zope.app.security==3.7.0". Later, it tries to resolve the dependencies of "zope.app.security==3.7.0" and finds "zope.component==3.6.0". Conflict! To avoid the conflict, "setuptools" would need to backtrack and revise its distribution decision for "zope.app.security" or alternatively first build the complete dependency graph and search a global solution. However, finding such a global solution requires a complex algorithm at least when efficiency is important (which probably is the case as the dependency graphs for larger applications will be huge). Thus: I appreaciate much your wish to solve this problem but expect that it will be quite complex. -- Dieter _______________________________________________ Zope-Dev maillist - Zope-Dev@zope.org http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
