Check correctly if package is loadable

homeassistant/util/package.py

@@ -32,7 +32,7 @@ def install_package(package: str, upgrade: bool = True,
     """
     # Not using 'import pip; pip.main([])' because it breaks the logger
     with INSTALL_LOCK:
-        if check_package_exists(package):
+        if package_loadable(package):
             return True
 
         _LOGGER.info('Attempting install of %s', package)
@@ -61,8 +61,8 @@ def install_package(package: str, upgrade: bool = True,
         return True
 
 
-def check_package_exists(package: str) -> bool:
-    """Check if a package is installed globally or in lib_dir.
+def package_loadable(package: str) -> bool:
+    """Check if a package is what will be loaded when we import it.
 
     Returns True when the requirement is met.
     Returns False when the package is not installed or doesn't meet req.
@@ -73,8 +73,14 @@ def check_package_exists(package: str) -> bool:
         # This is a zip file
         req = pkg_resources.Requirement.parse(urlparse(package).fragment)
 
-    env = pkg_resources.Environment()
-    return any(dist in req for dist in env[req.project_name])
+    for path in sys.path:
+        for dist in pkg_resources.find_distributions(path):
+            # If the project name is the same, it will be the one that is
+            # loaded when we import it.
+            if dist.project_name == req.project_name:
+                return dist in req
+
+    return False
 
 
 async def async_get_user_site(deps_dir: str) -> str:

tests/util/test_package.py

@@ -30,8 +30,8 @@ def mock_sys():
 
 @pytest.fixture
 def mock_exists():
-    """Mock check_package_exists."""
-    with patch('homeassistant.util.package.check_package_exists') as mock:
+    """Mock package_loadable."""
+    with patch('homeassistant.util.package.package_loadable') as mock:
         mock.return_value = False
         yield mock
 
@@ -193,12 +193,12 @@ def test_install_constraint(
 def test_check_package_global():
     """Test for an installed package."""
     installed_package = list(pkg_resources.working_set)[0].project_name
-    assert package.check_package_exists(installed_package)
+    assert package.package_loadable(installed_package)
 
 
 def test_check_package_zip():
     """Test for an installed zip package."""
-    assert not package.check_package_exists(TEST_ZIP_REQ)
+    assert not package.package_loadable(TEST_ZIP_REQ)
 
 
 @asyncio.coroutine
@@ -217,3 +217,25 @@ def test_async_get_user_site(mock_env_copy):
         stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.DEVNULL,
         env=env)
     assert ret == os.path.join(deps_dir, 'lib_dir')
+
+
+def test_package_loadable_installed_twice():
+    """Test that a package is loadable when installed twice.
+
+    If a package is installed twice, only the first version will be imported.
+    Test that package_loadable will only compare with the first package.
+    """
+    v1 = pkg_resources.Distribution(project_name='hello', version='1.0.0')
+    v2 = pkg_resources.Distribution(project_name='hello', version='2.0.0')
+
+    with patch('pkg_resources.find_distributions', side_effect=[[v1]]):
+        assert not package.package_loadable('hello==2.0.0')
+
+    with patch('pkg_resources.find_distributions', side_effect=[[v1], [v2]]):
+        assert not package.package_loadable('hello==2.0.0')
+
+    with patch('pkg_resources.find_distributions', side_effect=[[v2], [v1]]):
+        assert package.package_loadable('hello==2.0.0')
+
+    with patch('pkg_resources.find_distributions', side_effect=[[v2]]):
+        assert package.package_loadable('hello==2.0.0')