Fix resolution of packages with missing required extras

poetry/puzzle/provider.py

@@ -453,23 +453,19 @@ class Provider:
                     self.search_for_url(r)
 
         optional_dependencies = []
-        activated_extras = []
-        for extra in package.dependency.extras:
-            if extra not in package.extras:
-                continue
-
-            activated_extras.append(extra)
-            optional_dependencies += [d.name for d in package.extras[extra]]
-
         _dependencies = []
 
         # If some extras/features were required, we need to
         # add a special dependency representing the base package
         # to the current package
         if package.dependency.extras:
-            if activated_extras:
-                package = package.with_features(activated_extras)
+            for extra in package.dependency.extras:
+                if extra not in package.extras:
+                    continue
+
+                optional_dependencies += [d.name for d in package.extras[extra]]
 
+            package = package.with_features(list(package.dependency.extras))
             _dependencies.append(package.without_features().to_dependency())
 
         for dep in requires:

poetry/repositories/repository.py

@@ -24,14 +24,9 @@ class Repository(BaseRepository):
     def package(self, name, version, extras=None):
         name = name.lower()
 
-        if extras is None:
-            extras = []
-
         for package in self.packages:
             if name == package.name and package.version.text == version:
-                package = package.with_features(extras)
-
-                return package
+                return package.clone()
 
     def find_packages(self, dependency):
         constraint = dependency.constraint

tests/puzzle/test_solver.py

@@ -2435,7 +2435,6 @@ def test_solver_can_resolve_transitive_extras(solver, repo, package):
     requests = get_package("requests", "2.24.0")
     requests.add_dependency(Factory.create_dependency("certifi", ">=2017.4.17"))
     dep = get_dependency("PyOpenSSL", ">=0.14")
-    dep.in_extras.append("security")
     requests.add_dependency(
         Factory.create_dependency("PyOpenSSL", {"version": ">=0.14", "optional": True})
     )
@@ -2465,6 +2464,41 @@ def test_solver_can_resolve_transitive_extras(solver, repo, package):
     )
 
 
+def test_solver_can_resolve_for_packages_with_missing_extras(solver, repo, package):
+    package.add_dependency(
+        Factory.create_dependency(
+            "django-anymail", {"version": "^6.0", "extras": ["postmark"]}
+        )
+    )
+
+    django_anymail = get_package("django-anymail", "6.1.0")
+    django_anymail.add_dependency(Factory.create_dependency("django", ">=2.0"))
+    django_anymail.add_dependency(Factory.create_dependency("requests", ">=2.4.3"))
+    django_anymail.add_dependency(
+        Factory.create_dependency("boto3", {"version": "*", "optional": True})
+    )
+    django_anymail.extras["amazon_ses"] = [Factory.create_dependency("boto3", "*")]
+    django = get_package("django", "2.2.0")
+    boto3 = get_package("boto3", "1.0.0")
+    requests = get_package("requests", "2.24.0")
+
+    repo.add_package(django_anymail)
+    repo.add_package(django)
+    repo.add_package(boto3)
+    repo.add_package(requests)
+
+    ops = solver.solve()
+
+    check_solver_result(
+        ops,
+        [
+            {"job": "install", "package": django},
+            {"job": "install", "package": requests},
+            {"job": "install", "package": django_anymail},
+        ],
+    )
+
+
 def test_solver_can_resolve_python_restricted_package_dependencies(
     solver, repo, package, locked
 ):