Improve dependency resolution speed

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Changed
 
 - Improved dependency resolution to avoid unnecessary operations.
+- Improved dependency resolution speed.
 
 
 ## [0.6.5] - 2018-03-22

poetry/console/commands/debug/resolve.py

@@ -43,6 +43,7 @@ class DebugResolveCommand(Command):
             self.poetry.package,
             self.poetry.pool,
             Repository(),
+            Repository(),
             self.output
         )
 

poetry/mixology/resolution.py

@@ -16,7 +16,6 @@ from .dependency_graph import DependencyGraph
 from .helpers import flat_map
 from .possibility_set import PossibilitySet
 from .state import DependencyState
-from .state import ResolutionState
 from .unwind_details import UnwindDetails
 from .utils import unique
 

poetry/puzzle/provider.py

@@ -33,6 +33,8 @@ class Provider(SpecificationProvider):
         self._package = package
         self._pool = pool
         self._python_constraint = package.python_constraint
+        self._base_dg = DependencyGraph()
+        self._search_for = {}
 
     @property
     def pool(self) -> Pool:
@@ -59,6 +61,9 @@ class Provider(SpecificationProvider):
         The specifications in the returned list will be considered in reverse
         order, so the latest version ought to be last.
         """
+        if dependency in self._search_for:
+            return self._search_for[dependency]
+
         if dependency.is_vcs():
             return self.search_for_vcs(dependency)
 
@@ -76,7 +81,9 @@ class Provider(SpecificationProvider):
             )
         )
 
-        return packages
+        self._search_for[dependency] = packages
+
+        return self._search_for[dependency]
 
     def search_for_vcs(self, dependency: VCSDependency) -> List[Package]:
         """
@@ -190,6 +197,7 @@ class Provider(SpecificationProvider):
                           conflicts: Dict[str, List[Conflict]]):
         return sorted(dependencies, key=lambda d: [
             0 if activated.vertex_named(d.name).payload else 1,
+            0 if activated.vertex_named(d.name).root else 1,
             0 if d.allows_prereleases() else 1,
             0 if d.name in conflicts else 1,
             0 if activated.vertex_named(d.name).payload else len(self.search_for(d))

poetry/puzzle/ui.py

 from cleo.styles import CleoStyle
-from cleo.helpers import ProgressIndicator
 from poetry.mixology.contracts import UI as BaseUI