Resolve Empty Sub-Commands Lists

- Resolves Issue #444

CHANGELOG.md

@@ -10,6 +10,8 @@ Bugs:
 
 - `[ext.redis]` Unable To Set Redis Host
     - [Issue #440](https://github.com/datafolklabs/cement/issues/440)
+- `[ext.argparse]` Empty Sub-Commands List
+    - [Issue #444](https://github.com/datafolklabs/cement/issues/444)
 
 
 Features:

Makefile

@@ -6,7 +6,7 @@ dev:
 	docker-compose up -d
 	docker-compose exec cement /bin/ash
 
-test:
+test: comply
 	python -m pytest -v --cov=cement --cov-report=term --cov-report=html:coverage-report tests/
 
 comply:

cement/ext/ext_argparse.py

@@ -656,9 +656,18 @@ class ArgparseController(ControllerHandler):
         # parsers['base'].parse_args()
 
         kwargs = self._get_subparser_options(self)
-        sub = self.app.args.add_subparsers(**kwargs)
 
-        parents['base'] = sub
+        # only create a subparser if there are commands or nested
+        # controllers
+        cmds = self._collect_commands()
+        contrs = [x for x in self._controllers
+                  if x._meta.label != self._meta.label and
+                  x._meta.stacked_on == self._meta.label]
+
+        if len(cmds) > 0 or len(contrs) > 0:
+            sub = self.app.args.add_subparsers(**kwargs)
+            parents['base'] = sub
+
         base_parser_options = self._get_parser_options(self)
         for key, val in base_parser_options.items():
             setattr(self.app.args, key, val)
@@ -701,7 +710,16 @@ class ArgparseController(ControllerHandler):
                 # we need to add subparsers to this parser so we can
                 # attach commands and other nested controllers to it
                 kwargs = self._get_subparser_options(contr)
-                parents[label] = parsers[label].add_subparsers(**kwargs)
+
+                # only create a subparser if there are commands or nested
+                # controllers
+                cmds = contr._collect_commands()
+                contrs = [x for x in self._controllers
+                          if x._meta.label != label and
+                          x._meta.stacked_on == label]
+
+                if len(cmds) > 0 or len(contrs) > 0:
+                    parents[label] = parsers[label].add_subparsers(**kwargs)
 
                 # add an invisible controller option so we can figure out what
                 # to call later in self._dispatch

docker/Dockerfile.dev

@@ -13,4 +13,5 @@ RUN apk update \
         make \
     && pip install --no-cache-dir -r requirements-dev.txt
 COPY . /app
+RUN python setup.py develop
 CMD ["/bin/ash"]