diff --git a/lib/spack/spack/cmd/activate.py b/lib/spack/spack/cmd/activate.py
index a5909df9fb..12a743161d 100644
--- a/lib/spack/spack/cmd/activate.py
+++ b/lib/spack/spack/cmd/activate.py
@@ -61,4 +61,5 @@ def activate(parser, args):
     if spec.package.is_activated(extensions_layout=layout):
         tty.die("Package %s is already activated." % specs[0].short_spec)
 
-    spec.package.do_activate(extensions_layout=layout)
+    spec.package.do_activate(extensions_layout=layout,
+                             with_dependencies=not args.force)
diff --git a/lib/spack/spack/filesystem_view.py b/lib/spack/spack/filesystem_view.py
index 9be55e381b..1c6e5f0523 100644
--- a/lib/spack/spack/filesystem_view.py
+++ b/lib/spack/spack/filesystem_view.py
@@ -94,7 +94,7 @@ def add_specs(self, *specs, **kwargs):
 
     def add_extension(self, spec):
         """
-            Add (link) an extension in this view.
+            Add (link) an extension in this view. Does not add dependencies.
         """
         raise NotImplementedError
 
@@ -228,6 +228,9 @@ def add_extension(self, spec):
         try:
             if not spec.package.is_activated(self.extensions_layout):
                 spec.package.do_activate(
+                    ignore_conflicts=self.ignore_conflicts,
+                    with_dependencies=False,  # already taken care of
+                                              # in add_specs()
                     verbose=self.verbose,
                     extensions_layout=self.extensions_layout)
 
diff --git a/lib/spack/spack/package.py b/lib/spack/spack/package.py
index f0f092015f..f7cb3b0253 100644
--- a/lib/spack/spack/package.py
+++ b/lib/spack/spack/package.py
@@ -1825,12 +1825,17 @@ def _sanity_check_extension(self):
             raise ActivationError("%s does not extend %s!" %
                                   (self.name, self.extendee.name))
 
-    def do_activate(self, force=False, verbose=True, extensions_layout=None):
+    def do_activate(self, with_dependencies=True, ignore_conflicts=False,
+                    verbose=True, extensions_layout=None):
         """Called on an extension to invoke the extendee's activate method.
 
         Commands should call this routine, and should not call
         activate() directly.
         """
+        if verbose:
+            tty.msg("Activating extension %s for %s" %
+                    (self.spec.cshort_spec, self.extendee_spec.cshort_spec))
+
         self._sanity_check_extension()
 
         if extensions_layout is None:
@@ -1840,16 +1845,19 @@ def do_activate(self, force=False, verbose=True, extensions_layout=None):
             self.extendee_spec, self.spec)
 
         # Activate any package dependencies that are also extensions.
-        if not force:
+        if with_dependencies:
             for spec in self.dependency_activations():
                 if not spec.package.is_activated(
                         extensions_layout=extensions_layout):
                     spec.package.do_activate(
-                        force=force, verbose=verbose,
+                        with_dependencies=with_dependencies,
+                        ignore_conflicts=ignore_conflicts,
+                        verbose=verbose,
                         extensions_layout=extensions_layout)
 
         self.extendee_spec.package.activate(
-            self, extensions_layout=extensions_layout, **self.extendee_args)
+            self, extensions_layout=extensions_layout,
+            ignore_conflicts=ignore_conflicts, **self.extendee_args)
 
         extensions_layout.add_extension(self.extendee_spec, self.spec)
 
@@ -1863,7 +1871,7 @@ def dependency_activations(self):
         return (spec for spec in self.spec.traverse(root=False, deptype='run')
                 if spec.package.extends(self.extendee_spec))
 
-    def activate(self, extension, **kwargs):
+    def activate(self, extension, ignore_conflicts=False, **kwargs):
         """Make extension package usable by linking all its files to a target
         provided by the directory layout (depending if the user wants to
         activate globally or in a specified file system view).
@@ -1883,11 +1891,18 @@ def ignore(filename):
                     kwargs.get('ignore', lambda f: False)(filename))
 
         tree = LinkTree(extension.prefix)
+
         conflict = tree.find_conflict(target, ignore=ignore)
-        if conflict:
+        if not conflict:
+            pass
+        elif ignore_conflicts:
+            tty.warn("While activating %s, found conflict %s" %
+                     (self.spec.cshort_spec, conflict))
+        else:
             raise ExtensionConflictError(conflict)
 
-        tree.merge(target, ignore=ignore, link=extensions_layout.link)
+        tree.merge(target, ignore=ignore, link=extensions_layout.link,
+                   ignore_conflicts=ignore_conflicts)
 
     def do_deactivate(self, **kwargs):
         """Called on the extension to invoke extendee's deactivate() method.