Fix resolving directory dependencies with no sub dependencies

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 - Fixed the way packages information are retrieved for legacy repositories.
 - Fixed an error when adding packages with invalid versions.
+- Fixed an error when resolving directory dependencies with no sub dependencies.
 
 
 ## [0.12.10] - 2018-11-22

poetry/utils/helpers.py

@@ -5,6 +5,7 @@
 import tempfile
 
 from contextlib import contextmanager
+from typing import List
 from typing import Optional
 from typing import Union
 
@@ -41,7 +42,7 @@ def temporary_directory(*args, **kwargs):
         shutil.rmtree(name)
 
 
-def parse_requires(requires):  # type: (str) -> Union[list, None]
+def parse_requires(requires):  # type: (str) -> List[str]
     lines = requires.split("\n")
 
     requires_dist = []
@@ -79,8 +80,7 @@ def parse_requires(requires):  # type: (str) -> Union[list, None]
 
         requires_dist.append(line)
 
-    if requires_dist:
-        return requires_dist
+    return requires_dist
 
 
 def get_http_basic_auth(

tests/fixtures/git/github.com/demo/no-dependencies/demo/__init__.py

@@ -0,0 +1 @@
+__version__ = "1.2.3"

tests/fixtures/git/github.com/demo/no-dependencies/setup.py

@@ -0,0 +1,17 @@
+# -*- coding: utf-8 -*-
+from setuptools import setup
+
+
+kwargs = dict(
+    name="demo",
+    license="MIT",
+    version="0.1.2",
+    description="Demo project.",
+    author="Sébastien Eustace",
+    author_email="[email protected]",
+    url="https://github.com/demo/demo",
+    packages=["demo"],
+)
+
+
+setup(**kwargs)

tests/puzzle/test_provider.py

@@ -227,6 +227,28 @@ def test_search_for_directory_setup_read_setup_with_extras(provider, mocker):
     }
 
 
+@pytest.mark.skipif(not PY35, reason="AST parsing does not work for Python <3.4")
+def test_search_for_directory_setup_read_setup_with_no_dependencies(provider, mocker):
+    mocker.patch("poetry.utils.env.Env.get", return_value=MockEnv())
+
+    dependency = DirectoryDependency(
+        "demo",
+        Path(__file__).parent.parent
+        / "fixtures"
+        / "git"
+        / "github.com"
+        / "demo"
+        / "no-dependencies",
+    )
+
+    package = provider.search_for_directory(dependency)[0]
+
+    assert package.name == "demo"
+    assert package.version.text == "0.1.2"
+    assert package.requires == []
+    assert package.extras == {}
+
+
 def test_search_for_directory_poetry(provider):
     dependency = DirectoryDependency(
         "demo", Path(__file__).parent.parent / "fixtures" / "project_with_extras"