diff options
Diffstat (limited to 'pkg_resources/__init__.py')
| -rw-r--r-- | pkg_resources/__init__.py | 33 |
1 files changed, 29 insertions, 4 deletions
diff --git a/pkg_resources/__init__.py b/pkg_resources/__init__.py index bcee9d28..0846c0ac 100644 --- a/pkg_resources/__init__.py +++ b/pkg_resources/__init__.py @@ -317,8 +317,34 @@ class ResolutionError(Exception): def __repr__(self): return self.__class__.__name__+repr(self.args) + class VersionConflict(ResolutionError): - """An already-installed version conflicts with the requested version""" + """ + An already-installed version conflicts with the requested version. + + Should be initialized with the installed Distribution, the requested + Requirement, and optionally a list of dists that required the installed + Distribution. + """ + + @property + def dist(self): + return self.args[0] + + @property + def req(self): + return self.args[1] + + @property + def required_by(self): + return self.args[2] if len(self.args) > 2 else [] + + def report(self): + template = "{self.dist} is installed but {self.req} is required" + if self.required_by: + template += " by {self.required_by}" + return template.format(**locals()) + class DistributionNotFound(ResolutionError): """A requested distribution was not found""" @@ -763,9 +789,8 @@ class WorkingSet(object): to_activate.append(dist) if dist not in req: # Oops, the "best" so far conflicts with a dependency - tmpl = "%s is installed but %s is required by %s" - args = dist, req, list(required_by.get(req, [])) - raise VersionConflict(tmpl % args) + dependent_req = list(required_by.get(req, [])) + raise VersionConflict(dist, req, dependent_req) # push the new requirements onto the stack new_requirements = dist.requires(req.extras)[::-1] |