Fix handling of Python constraints when solving dependencies (#377)

poetry/masonry/metadata.py

@@ -64,7 +64,7 @@ class Metadata:
         meta.maintainer_email = meta.author_email
         meta.maintainer_email = meta.author_email
 
 
         # Requires python
         # Requires python
-        if not package.python_constraint.is_any():
+        if package.python_versions != "*":
             meta.requires_python = format_python_constraint(package.python_constraint)
             meta.requires_python = format_python_constraint(package.python_constraint)
 
 
         meta.requires_dist = [d.to_pep_508() for d in package.requires]
         meta.requires_dist = [d.to_pep_508() for d in package.requires]

poetry/packages/project_package.py

+from poetry.semver import VersionRange
+from poetry.semver import parse_constraint
+
 from .package import Package
 from .package import Package
 
 
 
 
@@ -10,6 +13,9 @@ class ProjectPackage(Package):
         self.include = []
         self.include = []
         self.exclude = []
         self.exclude = []
 
 
+        if self._python_versions == "*":
+            self._python_constraint = parse_constraint("~2.7 || >=3.4")
+
     def is_root(self):
     def is_root(self):
         return True
         return True
 
 
@@ -19,3 +25,15 @@ class ProjectPackage(Package):
         dependency.is_root = True
         dependency.is_root = True
 
 
         return dependency
         return dependency
+
+    @property
+    def python_versions(self):
+        return self._python_versions
+
+    @python_versions.setter
+    def python_versions(self, value):
+        self._python_versions = value
+        if value == "*" or value == VersionRange():
+            value = "~2.7 || >=3.4"
+
+        self._python_constraint = parse_constraint(value)

poetry/puzzle/provider.py

@@ -311,21 +311,27 @@ class Provider:
         else:
         else:
             dependencies = package.requires
             dependencies = package.requires
 
 
-        if not self._package.python_constraint.allows_any(package.python_constraint):
-            return [
-                Incompatibility(
-                    [Term(package.to_dependency(), True)],
-                    PythonCause(package.python_versions, self._package.python_versions),
-                )
-            ]
-
-        if not self._package.platform_constraint.matches(package.platform_constraint):
-            return [
-                Incompatibility(
-                    [Term(package.to_dependency(), True)],
-                    PlatformCause(package.platform),
-                )
-            ]
+            if not package.python_constraint.allows_all(
+                self._package.python_constraint
+            ):
+                return [
+                    Incompatibility(
+                        [Term(package.to_dependency(), True)],
+                        PythonCause(
+                            package.python_versions, self._package.python_versions
+                        ),
+                    )
+                ]
+
+            if not self._package.platform_constraint.matches(
+                package.platform_constraint
+            ):
+                return [
+                    Incompatibility(
+                        [Term(package.to_dependency(), True)],
+                        PlatformCause(package.platform),
+                    )
+                ]
 
 
         dependencies = [
         dependencies = [
             dep
             dep

tests/puzzle/test_solver.py

@@ -291,17 +291,17 @@ def test_solver_sets_categories(solver, repo, package):
 
 
 
 
 def test_solver_respects_root_package_python_versions(solver, repo, package):
 def test_solver_respects_root_package_python_versions(solver, repo, package):
-    package.python_versions = "^3.4"
+    package.python_versions = "~3.4"
     package.add_dependency("A")
     package.add_dependency("A")
     package.add_dependency("B")
     package.add_dependency("B")
 
 
     package_a = get_package("A", "1.0")
     package_a = get_package("A", "1.0")
     package_b = get_package("B", "1.0")
     package_b = get_package("B", "1.0")
-    package_b.python_versions = "^3.6"
+    package_b.python_versions = "^3.3"
     package_c = get_package("C", "1.0")
     package_c = get_package("C", "1.0")
-    package_c.python_versions = "^3.6"
+    package_c.python_versions = "^3.4"
     package_c11 = get_package("C", "1.1")
     package_c11 = get_package("C", "1.1")
-    package_c11.python_versions = "~3.3"
+    package_c11.python_versions = "^3.6"
     package_b.add_dependency("C", "^1.0")
     package_b.add_dependency("C", "^1.0")
 
 
     repo.add_package(package_a)
     repo.add_package(package_a)
@@ -342,16 +342,16 @@ def test_solver_fails_if_mismatch_root_python_versions(solver, repo, package):
 
 
 
 
 def test_solver_solves_optional_and_compatible_packages(solver, repo, package):
 def test_solver_solves_optional_and_compatible_packages(solver, repo, package):
-    package.python_versions = "^3.4"
+    package.python_versions = "~3.4"
     package.extras["foo"] = [get_dependency("B")]
     package.extras["foo"] = [get_dependency("B")]
-    package.add_dependency("A", {"version": "*", "python": "~3.5"})
+    package.add_dependency("A", {"version": "*", "python": "^3.4"})
     package.add_dependency("B", {"version": "*", "optional": True})
     package.add_dependency("B", {"version": "*", "optional": True})
 
 
     package_a = get_package("A", "1.0")
     package_a = get_package("A", "1.0")
     package_b = get_package("B", "1.0")
     package_b = get_package("B", "1.0")
-    package_b.python_versions = "^3.6"
+    package_b.python_versions = "^3.3"
     package_c = get_package("C", "1.0")
     package_c = get_package("C", "1.0")
-    package_c.python_versions = "^3.6"
+    package_c.python_versions = "^3.4"
     package_b.add_dependency("C", "^1.0")
     package_b.add_dependency("C", "^1.0")
 
 
     repo.add_package(package_a)
     repo.add_package(package_a)
@@ -377,7 +377,6 @@ def test_solver_solves_while_respecting_root_platforms(solver, repo, package):
 
 
     package_a = get_package("A", "1.0")
     package_a = get_package("A", "1.0")
     package_b = get_package("B", "1.0")
     package_b = get_package("B", "1.0")
-    package_b.python_versions = "^3.6"
     package_c12 = get_package("C", "1.2")
     package_c12 = get_package("C", "1.2")
     package_c12.platform = "win32"
     package_c12.platform = "win32"
     package_c10 = get_package("C", "1.0")
     package_c10 = get_package("C", "1.0")