diff options
Diffstat (limited to 'pkg_resources.py')
| -rw-r--r-- | pkg_resources.py | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/pkg_resources.py b/pkg_resources.py index 6f21b0bf..daf7732c 100644 --- a/pkg_resources.py +++ b/pkg_resources.py @@ -602,6 +602,10 @@ class WorkingSet(object): best = {} to_activate = [] + # Mapping of requirement to set of distributions that required it; + # useful for reporting info about conflicts. + required_by = collections.defaultdict(set) + while requirements: # process dependencies breadth-first req = requirements.pop(0) @@ -635,9 +639,18 @@ class WorkingSet(object): to_activate.append(dist) if dist not in req: # Oops, the "best" so far conflicts with a dependency - # XXX put more info here - raise VersionConflict(dist, req) - requirements.extend(dist.requires(req.extras)[::-1]) + tmpl = "%s is installed but %s is required by %s" + args = dist, req, list(required_by.get(req, [])) + raise VersionConflict(tmpl % args) + + # push the new requirements onto the stack + new_requirements = dist.requires(req.extras)[::-1] + requirements.extend(new_requirements) + + # Register the new requirements needed by req + for new_requirement in new_requirements: + required_by[new_requirement].add(req.project_name) + processed[req] = True # return list of distros to activate |