Tolerate missing bindep.txt when using --profiles

When just trying to determine the list of possible platform profiles, it
seems silly to need to `touch bindep.txt`.

Note that we'll still log the error about how neither bindep.txt nor
other-requirements.txt exists

Change-Id: I6ab187cdfb7d8fc5638880bcffea6800f5227c79

bindep/depends.py

@@ -68,11 +68,14 @@ PY2 = "base-py2"
 PY3 = "base-py3"
 
 
-def get_depends(filename=None):
+def get_depends(filename=None, default_blank=False):
     fd = get_depends_file(filename)
     if not fd:
-        return None
-    return Depends(fd.read())
+        if default_blank:
+            return Depends("")
+        else:
+            return None
+    return Depends(fd.read(), filename)
 
 
 def get_depends_file(filename=None):
@@ -132,15 +135,18 @@ class Depends(object):
         (True, True): True,
     }
 
-    def __init__(self, depends_string):
+    def __init__(self, depends_string, filename=None):
         """Construct a Depends instance.
 
         :param depends_string: The string description of the requirements that
             need to be satisfied. See the bindep README.rst for syntax for the
             requirements list.
+        :param filename: The string name of the file from which requirements
+            were loaded.
         """
         parser = makeGrammar(grammar, {})(depends_string)
         self._rules = parser.rules()
+        self.filename = filename
 
     def _partition(self, rule):
         """Separate conditions into platform and user profiles.

bindep/main.py

@@ -53,7 +53,9 @@ def main(depends=None):
     args = parser.parse_args()
 
     if depends is None:
-        depends = bindep.depends.get_depends(args.filename)
+        depends = bindep.depends.get_depends(
+            args.filename,
+            default_blank=args.profiles)
         if not depends:
             return 1
 
@@ -61,10 +63,12 @@ def main(depends=None):
         logging.info("Platform profiles:")
         for profile in depends.platform_profiles():
             logging.info("%s", profile)
-        logging.info("")
-        logging.info("Configuration profiles:")
-        for profile in depends.profiles():
-            logging.info("%s", profile)
+
+        if depends.filename:
+            logging.info("")
+            logging.info("Configuration profiles:")
+            for profile in depends.profiles():
+                logging.info("%s", profile)
         return 0
 
     profiles = args.profile + depends.platform_profiles()

bindep/tests/test_depends.py

@@ -70,6 +70,12 @@ class DistroFixture(fixtures.Fixture):
 
 class TestDepends(TestCase):
 
+    def test_filename(self):
+        depends = Depends("")
+        self.assertIsNone(depends.filename)
+        depends = Depends("", "/some/path/to/bindep.txt")
+        self.assertEqual(depends.filename, "/some/path/to/bindep.txt")
+
     def test_empty_file(self):
         depends = Depends("")
         self.assertEqual([], depends.profiles())

bindep/tests/test_main.py

@@ -53,6 +53,8 @@ class TestMain(TestCase):
         self.useFixture(MonkeyPatch('sys.argv', ['bindep', '--profiles']))
 
         class TestFactory:
+            filename = 'some/bindep.txt'
+
             def platform_profiles(self):
                 return ['platform:ubuntu', 'platform:i386']
 
@@ -69,6 +71,25 @@ class TestMain(TestCase):
             foo
             """), logger.output)
 
+    def test_profiles_lists_profiles_no_file_loaded(self):
+        logger = self.useFixture(FakeLogger())
+        self.useFixture(MonkeyPatch('sys.argv', ['bindep', '--profiles']))
+
+        class TestFactory:
+            filename = None
+
+            def platform_profiles(self):
+                return ['platform:ubuntu', 'platform:i386']
+
+            def profiles(self):
+                return []
+        self.assertEqual(0, main(depends=TestFactory()))
+        self.assertEqual(dedent("""\
+            Platform profiles:
+            platform:ubuntu
+            platform:i386
+            """), logger.output)
+
     def test_missing_default_requirements_file(self):
         fixture = self.useFixture(MainFixture())
         self.useFixture(MonkeyPatch('sys.argv', ['bindep']))