Deprecate the usage of certain objects via certain modules

As an example, this displays a deprecation warning for the use of
"bb.encodeurl" when you should be using "bb.fetch.encodeurl".  It includes a
convenience function for this purpose.  It should be of use when moving
objects between modules permanently, changing the API the user sees.

(Bitbake rev: 78f56049ba863b2e585b89db12b32697eb879bbc)

Signed-off-by: Chris Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

bitbake/lib/bb/__init__.py

@@ -52,7 +52,45 @@ def fatal(*args):
     bb.msg.fatal(None, ''.join(args))
 
 
+def deprecated(func, name = None, advice = ""):
+    """This is a decorator which can be used to mark functions
+    as deprecated. It will result in a warning being emmitted
+    when the function is used."""
+    import warnings
+
+    if advice:
+        advice = ": %s" % advice
+    if name is None:
+        name = func.__name__
+
+    def newFunc(*args, **kwargs):
+        warnings.warn("Call to deprecated function %s%s." % (name,
+                                                             advice),
+                      category = DeprecationWarning,
+                      stacklevel = 2)
+        return func(*args, **kwargs)
+    newFunc.__name__ = func.__name__
+    newFunc.__doc__ = func.__doc__
+    newFunc.__dict__.update(func.__dict__)
+    return newFunc
+
 # For compatibility
-from bb.fetch import MalformedUrl, encodeurl, decodeurl
-from bb.utils import mkdirhier, movefile, copyfile, which
-from bb.utils import vercmp_string as vercmp
+def deprecate_import(current, modulename, fromlist, renames = None):
+    """Import objects from one module into another, wrapping them with a DeprecationWarning"""
+    import sys
+
+    module = __import__(modulename, fromlist = fromlist)
+    for position, objname in enumerate(fromlist):
+        obj = getattr(module, objname)
+        newobj = deprecated(obj, "{0}.{1}".format(current, objname),
+                            "Please use {0}.{1} instead".format(modulename, objname))
+        if renames:
+            newname = renames[position]
+        else:
+            newname = objname
+
+        setattr(sys.modules[current], newname, newobj)
+
+deprecate_import(__name__, "bb.fetch", ("MalformedUrl", "encodeurl", "decodeurl"))
+deprecate_import(__name__, "bb.utils", ("mkdirhier", "movefile", "copyfile", "which"))
+deprecate_import(__name__, "bb.utils", ["vercmp_string"], ["vercmp"])

bitbake/lib/bb/parse/parse_py/BBHandler.py

@@ -33,7 +33,7 @@ from ConfHandler import include, init
 from bb.parse import resolve_file, ast
 
 # For compatibility
-from bb.parse import vars_from_file
+bb.deprecate_import(__name__, "bb.parse", ["vars_from_file"])
 
 __func_start_regexp__    = re.compile( r"(((?P<py>python)|(?P<fr>fakeroot))\s*)*(?P<func>[\w\.\-\+\{\}\$]+)?\s*\(\s*\)\s*{$" )
 __inherit_regexp__       = re.compile( r"inherit\s+(.+)" )