Simplify loader functionality

.gitignore

@@ -1,4 +1,5 @@
 docs/_build
 .coverage
-*.egg-info
 .tox
+*.egg-info
+*.pyc

dev-requirements.txt

@@ -1,6 +1,6 @@
 # Docs
 Sphinx>=1.1.2
-releases>=0.2.0
+releases>=0.2.4
 # Testing (explicit dependencies to get around a Travis/pip issue)
 # For now, need master as 1.3 isn't out yet :(
 #nose>=1.3

invoke/cli.py

@@ -4,11 +4,11 @@
 
 from .vendor import six
 
+from .collection import Collection
 from .context import Context
-from .loader import Loader
 from .parser import Parser, Context as ParserContext, Argument
 from .executor import Executor
-from .exceptions import Failure, CollectionNotFound, ParseError
+from .exceptions import Failure, ParseError
 from .util import debug, pty_size
 from ._version import __version__
 
@@ -48,7 +48,6 @@ def print_help(tuples):
     print('')
 
 
-
 def parse_gracefully(parser, argv):
     """
     Run ``parser.parse_argv(argv)`` & gracefully handle ``ParseError``.
@@ -148,7 +147,7 @@ def parse(argv, collection=None):
     # TODO: if this wants to display context sensitive help (e.g. a combo help
     # and available tasks listing; or core flags modified by plugins/task
     # modules) it will have to move farther down.
-    if args.help.value == True:
+    if args.help.value is True:
         print("Usage: inv[oke] [--core-opts] task1 [--task1-opts] ... taskN [--taskN-opts]")
         print("")
         print("Core options:")
@@ -159,8 +158,8 @@ def parse(argv, collection=None):
     # (Skip loading if somebody gave us an explicit task collection.)
     if not collection:
         debug("No collection given, loading from %r" % args.root.value)
-        loader = Loader(root=args.root.value)
-        collection = loader.load_collection(args.collection.value)
+        name, root = args.collection.value, args.root.value
+        collection = Collection.load_collection(name, root)
     parser = Parser(contexts=collection.to_contexts())
     debug("Parsing actual tasks against collection %r" % collection)
     tasks = parse_gracefully(parser, core.unparsed)

invoke/collection.py

@@ -1,18 +1,37 @@
 import copy
-from operator import add
+import imp
+import os
 import types
 
 from .vendor import six
 from .vendor.lexicon import Lexicon
 
-from .parser import Context, Argument
+from .exceptions import CollectionNotFound
+from .parser import Context
 from .tasks import Task
 
 
+def _parent_dirs(root=None):
+    if root is None:
+        root = os.getcwd()
+    roots = [os.path.abspath(root)]
+    # Accumulate all parent directories
+    roots.append(os.path.dirname(roots[-1]))
+    while roots[-1] != roots[-2]:
+        roots.append(os.path.dirname(roots[-1]))
+    # Make sure we haven't got duplicates on the end
+    if roots[-1] == roots[-2]:
+        roots = roots[:-1]
+    return roots
+
+
 class Collection(object):
     """
     A collection of executable tasks.
     """
+
+    default_module_name = 'tasks'
+
     def __init__(self, *args, **kwargs):
         """
         Create a new task collection/namespace.
@@ -294,3 +313,28 @@ def configure(self, options):
         :returns: ``None``.
         """
         self._configuration.update(options)
+
+    @classmethod
+    def load_collection(cls, name=None, root=None):
+        """
+        Try find find the module ``name``, recursively from the
+        directory ``root``.
+
+        default: name = 'tasks', root = current working directory.
+        """
+        if name is None:
+            # TODO: make this configurable
+            name = cls.default_module_name
+        roots = _parent_dirs(root)
+        # Try to find the module
+        try:
+            file, pathname, desc = imp.find_module(name, roots)
+        except ImportError:
+            raise CollectionNotFound(name=name, root=root)
+        # Try to load it, then close the file we found
+        try:
+            module = imp.load_module(name, file, pathname, desc)
+        finally:
+            file.close()
+
+        return Collection.from_module(module)

tests/_support/tree.out

@@ -3,7 +3,6 @@
 │   ├── cli.rst
 │   ├── collection.rst
 │   ├── exceptions.rst
-│   ├── loader.rst
 │   ├── parser
 │   │   ├── argument.rst
 │   │   ├── context.rst