Fix packages not found for prerelease version constraints when resolving dependencies.

CHANGELOG.md

 # Change Log
 # Change Log
 
 
+## [Unreleased]
+
+### Fixed
+
+- Fixed packages not found for prerelease version constraints when resolving dependencies.
+
+
 ## [0.10.0] - 2018-05-28
 ## [0.10.0] - 2018-05-28
 
 
 ### Added
 ### Added

poetry/puzzle/provider.py

@@ -122,11 +122,11 @@ class Provider:
             )
             )
 
 
             packages.sort(
             packages.sort(
-                key=cmp_to_key(
-                    lambda x, y:
-                    0 if x.version == y.version
-                    else int(x.version < y.version or -1)
-                )
+                key=lambda p: (
+                    not p.is_prerelease() and not dependency.allows_prereleases(),
+                    p.version
+                ),
+                reverse=True
             )
             )
 
 
         self._search_for[dependency] = packages
         self._search_for[dependency] = packages

poetry/repositories/pypi_repository.py

@@ -108,7 +108,7 @@ class PyPiRepository(Repository):
 
 
             package = Package(name, version)
             package = Package(name, version)
 
 
-            if package.is_prerelease() and not allow_prereleases:
+            if package.is_prerelease() and not allow_prereleases and not constraint.allows(package.version):
                 continue
                 continue
 
 
             if (
             if (

poetry/repositories/repository.py

@@ -49,7 +49,11 @@ class Repository(BaseRepository):
 
 
         for package in self.packages:
         for package in self.packages:
             if name == package.name:
             if name == package.name:
-                if package.is_prerelease() and not allow_prereleases:
+                if (
+                    package.is_prerelease()
+                    and not allow_prereleases
+                    and not constraint.allows(package.version)
+                ):
                     continue
                     continue
 
 
                 if constraint is None or constraint.allows(package.version):
                 if constraint is None or constraint.allows(package.version):

tests/puzzle/test_solver.py

@@ -665,3 +665,25 @@ def test_solver_with_dependency_in_both_main_and_dev_dependencies_with_one_more_
     assert b.category == 'main'
     assert b.category == 'main'
     assert a.category == 'main'
     assert a.category == 'main'
     assert e.category == 'main'
     assert e.category == 'main'
+
+
+def test_solver_with_dependency_and_prerelease_sub_dependencies(solver, repo, package):
+    package.add_dependency('A')
+
+    package_a = get_package('A', '1.0')
+    package_a.add_dependency('B', '>=1.0.0.dev2')
+
+    repo.add_package(package_a)
+    repo.add_package(get_package('B', '0.9.0'))
+    repo.add_package(get_package('B', '1.0.0.dev1'))
+    repo.add_package(get_package('B', '1.0.0.dev2'))
+    repo.add_package(get_package('B', '1.0.0.dev3'))
+    package_b = get_package('B', '1.0.0.dev4')
+    repo.add_package(package_b)
+
+    ops = solver.solve()
+
+    check_solver_result(ops, [
+        {'job': 'install', 'package': package_b},
+        {'job': 'install', 'package': package_a},
+    ])

tests/repositories/test_pypi_repository.py

@@ -41,6 +41,13 @@ def test_find_packages():
     assert len(packages) == 5
     assert len(packages) == 5
 
 
 
 
+def test_find_packages_with_prereleases():
+    repo = MockRepository()
+    packages = repo.find_packages('toga', '>=0.3.0.dev2')
+
+    assert len(packages) == 7
+
+
 def test_package():
 def test_package():
     repo = MockRepository()
     repo = MockRepository()