Ensure Dynamic utility subscribes to dependent function

holoviews/core/accessors.py

@@ -4,6 +4,7 @@
 from __future__ import absolute_import, unicode_literals
 
 from collections import OrderedDict
+from types import FunctionType
 
 import param
 
@@ -84,24 +85,22 @@ def function(object, **kwargs):
         params = {p: val for p, val in kwargs.items()
                   if isinstance(val, param.Parameter)
                   and isinstance(val.owner, param.Parameterized)}
-        param_methods = {p: val for p, val in kwargs.items()
-                         if util.is_param_method(val, has_deps=True)}
+
+        dependent_kws = any(
+            (isinstance(val, FunctionType) and hasattr(val, '_dinfo')) or
+            util.is_param_method(val, has_deps=True) for val in kwargs.values()
+        )
 
         if dynamic is None:
             dynamic = (bool(streams) or isinstance(self._obj, DynamicMap) or
                        util.is_param_method(function, has_deps=True) or
-                       params or param_methods)
+                       params or dependent_kws)
 
         if applies and dynamic:
             return Dynamic(self._obj, operation=function, streams=streams,
                            kwargs=kwargs, link_inputs=link_inputs)
         elif applies:
-            inner_kwargs = dict(kwargs)
-            for k, v in kwargs.items():
-                if util.is_param_method(v, has_deps=True):
-                    inner_kwargs[k] = v()
-                elif k in params:
-                    inner_kwargs[k] = getattr(v.owner, v.name)
+            inner_kwargs = util.resolve_dependent_kwargs(kwargs)
             if hasattr(function, 'dynamic'):
                 inner_kwargs['dynamic'] = False
             return function(self._obj, **inner_kwargs)

holoviews/core/util.py

@@ -9,11 +9,12 @@
 import unicodedata
 import datetime as dt
 
-from distutils.version import LooseVersion as _LooseVersion
-from functools import partial
 from collections import defaultdict
 from contextlib import contextmanager
+from distutils.version import LooseVersion as _LooseVersion
+from functools import partial
 from threading import Thread, Event
+from types import FunctionType
 
 import numpy as np
 import param
@@ -26,7 +27,7 @@
 # Python3 compatibility
 if sys.version_info.major >= 3:
     import builtins as builtins   # noqa (compatibility)
-    
+
     basestring = str
     unicode = str
     long = int
@@ -38,7 +39,7 @@
     LooseVersion = _LooseVersion
 else:
     import __builtin__ as builtins # noqa (compatibility)
-    
+
     basestring = basestring
     unicode = unicode
     from itertools import izip
@@ -1466,6 +1467,35 @@ def is_param_method(obj, has_deps=False):
     return parameterized
 
 
+def resolve_dependent_kwargs(kwargs):
+    """Resolves parameter dependencies in the supplied dictionary
+
+    Resolves parameter values, Parameterized instance methods and
+    parameterized functions with dependencies in the supplied
+    dictionary.
+
+    Args:
+       kwargs (dict): A dictionary of keyword arguments
+
+    Returns:
+       A new dictionary with where any parameter dependencies have been
+       resolved.
+    """
+    resolved = {}
+    for k, v in kwargs.items():
+        if is_param_method(v, has_deps=True):
+            v = v()
+        elif isinstance(v, param.Parameter) and isinstance(v.owner, param.Parameterized):
+            v = getattr(v.owner, v.name)
+        elif isinstance(v, FunctionType) and hasattr(v, '_dinfo'):
+            deps = v._dinfo
+            args = (getattr(p.owner, p.name) for p in deps.get('dependencies', []))
+            kwargs = {k: getattr(p.owner, p.name) for k, p in deps.get('kw', {}).items()}
+            v = v(*args, **kwargs)
+        resolved[k] = v
+    return resolved
+
+
 @contextmanager
 def disable_constant(parameterized):
     """

holoviews/streams.py

@@ -635,7 +635,7 @@ class Params(Stream):
     parameters = param.List([], constant=True, doc="""
         Parameters on the parameterized to watch.""")
 
-    def __init__(self, parameterized=None, parameters=None, watch=True, **params):
+    def __init__(self, parameterized=None, parameters=None, watch=True, watch_only=False, **params):
         if util.param_version < '1.8.0' and watch:
             raise RuntimeError('Params stream requires param version >= 1.8.0, '
                                'to support watching parameters.')
@@ -655,6 +655,7 @@ def __init__(self, parameterized=None, parameters=None, watch=True, **params):
                     rename.update({(o, k): v for o in owners})
             params['rename'] = rename
 
+        self._watch_only = watch_only
         super(Params, self).__init__(parameterized=parameterized, parameters=parameters, **params)
         self._memoize_counter = 0
         self._events = []
@@ -728,6 +729,8 @@ def update(self, **kwargs):
 
     @property
     def contents(self):
+        if self._watch_only:
+            return {}
         filtered = {(p.owner, p.name): getattr(p.owner, p.name) for p in self.parameters}
         return {self._rename.get((o, n), n): v for (o, n), v in filtered.items()
                 if self._rename.get((o, n), True) is not None}
@@ -750,11 +753,9 @@ def __init__(self, parameterized, parameters=None, watch=True, **params):
         parameterized = util.get_method_owner(parameterized)
         if not parameters:
             parameters = [p.pobj for p in parameterized.param.params_depended_on(method.__name__)]
+        params['watch_only'] = True
         super(ParamMethod, self).__init__(parameterized, parameters, watch, **params)
 
-    @property
-    def contents(self):
-        return {}
 
 
 

holoviews/tests/core/testapply.py

@@ -109,6 +109,39 @@ def test_element_apply_param_method_with_dependencies(self):
         pinst.label = 'Another label'
         self.assertEqual(applied[()], self.element.relabel('Another label'))
 
+    def test_element_apply_function_with_dependencies(self):
+        pinst = ParamClass()
+
+        @param.depends(pinst.param.label)
+        def get_label(label):
+            return label + '!'
+
+        applied = self.element.apply('relabel', label=get_label)
+
+        # Check stream
+        self.assertEqual(len(applied.streams), 1)
+        stream = applied.streams[0]
+        self.assertIsInstance(stream, Params)
+        self.assertEqual(stream.parameters, [pinst.param.label])
+
+        # Check results
+        self.assertEqual(applied[()], self.element.relabel('Test!'))
+
+        # Ensure subscriber gets called
+        stream.add_subscriber(lambda **kwargs: applied[()])
+        pinst.label = 'Another label'
+        self.assertEqual(applied.last, self.element.relabel('Another label!'))
+
+    def test_element_apply_function_with_dependencies_non_dynamic(self):
+        pinst = ParamClass()
+
+        @param.depends(pinst.param.label)
+        def get_label(label):
+            return label + '!'
+
+        applied = self.element.apply('relabel', dynamic=False, label=get_label)
+        self.assertEqual(applied, self.element.relabel('Test!'))
+
     def test_element_apply_dynamic_with_param_method(self):
         pinst = ParamClass()
         applied = self.element.apply(lambda x, label: x.relabel(label), label=pinst.dynamic_label)

holoviews/util/__init__.py

@@ -898,6 +898,12 @@ def _get_streams(self, map_obj, watch=True):
         for value in self.p.kwargs.values():
             if util.is_param_method(value, has_deps=True):
                 streams.append(value)
+            elif isinstance(value, FunctionType) and hasattr(value, '_dinfo'):
+                dependencies = list(value._dinfo.get('dependencies', []))
+                dependencies += list(value._dinfo.get('kwargs', {}).values())
+                params = [d for d in dependencies if isinstance(d, param.Parameter)
+                          and isinstance(d.owner, param.Parameterized)]
+                streams.append(Params(parameters=params, watch_only=True))
 
         valid, invalid = Stream._process_streams(streams)
         if invalid:
@@ -915,33 +921,19 @@ def _process(self, element, key=None, kwargs={}):
         else:
             return self.p.operation(element, **kwargs)
 
-    def _eval_kwargs(self):
-        """Evaluates any parameterized methods in the kwargs"""
-        evaled_kwargs = {}
-        for k, v in self.p.kwargs.items():
-            if util.is_param_method(v):
-                v = v()
-            elif isinstance(v, FunctionType) and hasattr(v, '_dinfo'):
-                deps = v._dinfo
-                args = (getattr(p.owner, p.name) for p in deps.get('dependencies', []))
-                kwargs = {k: getattr(p.owner, p.name) for k, p in deps.get('kw', {}).items()}
-                v = v(*args, **kwargs)
-            evaled_kwargs[k] = v
-        return evaled_kwargs
-
     def _dynamic_operation(self, map_obj):
         """
         Generate function to dynamically apply the operation.
         Wraps an existing HoloMap or DynamicMap.
         """
         if not isinstance(map_obj, DynamicMap):
             def dynamic_operation(*key, **kwargs):
-                kwargs = dict(self._eval_kwargs(), **kwargs)
+                kwargs = dict(util.resolve_dependent_kwargs(self.p.kwargs), **kwargs)
                 obj = map_obj[key] if isinstance(map_obj, HoloMap) else map_obj
                 return self._process(obj, key, kwargs)
         else:
             def dynamic_operation(*key, **kwargs):
-                kwargs = dict(self._eval_kwargs(), **kwargs)
+                kwargs = dict(util.resolve_dependent_kwargs(self.p.kwargs), **kwargs)
                 if map_obj._posarg_keys and not key:
                     key = tuple(kwargs[k] for k in map_obj._posarg_keys)
                 return self._process(map_obj[key], key, kwargs)