1.1 --- a/importer.py	Mon Mar 13 01:56:13 2017 +0100
     1.2 +++ b/importer.py	Mon Mar 13 16:57:32 2017 +0100
     1.3 @@ -23,7 +23,7 @@
     1.4  from errors import ProgramError
     1.5  from os.path import exists, extsep, getmtime, join
     1.6  from os import listdir, makedirs, remove
     1.7 -from common import init_item, readfile, writefile
     1.8 +from common import init_item, order_dependencies, readfile, writefile
     1.9  from modules import CachedModule
    1.10  from referencing import Reference
    1.11  import inspector
    1.12 @@ -677,44 +677,10 @@
    1.13  
    1.14          self.condense_dependencies()
    1.15  
    1.16 -        # Record the number of modules using or depending on each module.
    1.17 -
    1.18 -        usage = {}
    1.19 -
    1.20 -        # Record path-based dependencies.
    1.21 -
    1.22 -        for path in self.depends.keys():
    1.23 -            usage[path] = set()
    1.24 -
    1.25 -        for path, depends in self.depends.items():
    1.26 -            for origin in depends:
    1.27 -                init_item(usage, origin, set)
    1.28 -                usage[origin].add(path)
    1.29 -
    1.30 -        # Produce an ordering by obtaining exposed modules (required by modules
    1.31 -        # already processed) and putting them at the start of the list.
    1.32 -
    1.33 -        ordered = []
    1.34 -
    1.35 -        while usage:
    1.36 -            have_next = False
    1.37 -
    1.38 -            for path, n in usage.items():
    1.39 -                if not n:
    1.40 -                    ordered.insert(0, path)
    1.41 -                    depends = self.depends.get(path)
    1.42 -
    1.43 -                    # Reduce usage of the referenced objects.
    1.44 -
    1.45 -                    if depends:
    1.46 -                        for origin in depends:
    1.47 -                            usage[origin].remove(path)
    1.48 -
    1.49 -                    del usage[path]
    1.50 -                    have_next = True
    1.51 -
    1.52 -            if not have_next:
    1.53 -                raise ProgramError("Modules with unresolvable dependencies exist: %s" % ", ".join(usage.keys()))
    1.54 +        try:
    1.55 +            ordered = order_dependencies(self.depends)
    1.56 +        except ValueError, exc:
    1.57 +            raise ProgramError("Modules with unresolvable dependencies exist: %s" % ", ".join(exc.args[0].keys()))
    1.58  
    1.59          if "__main__" in ordered:
    1.60              ordered.remove("__main__")