Add check for callable to 'Language.replace_pipe' to fix #3737 (#3741)

spacy/errors.py

@@ -383,6 +383,8 @@ class Errors(object):
     E133 = ("The sum of prior probabilities for alias '{alias}' should not exceed 1, "
             "but found {sum}.")
     E134 = ("Alias '{alias}' defined for unknown entity '{entity}'.")
+    E135 = ("If you meant to replace a built-in component, use `create_pipe`: "
+            "`nlp.replace_pipe('{name}', nlp.create_pipe('{name}'))`")
 
 
 @add_codes

spacy/language.py

@@ -333,6 +333,11 @@ class Language(object):
         """
         if name not in self.pipe_names:
             raise ValueError(Errors.E001.format(name=name, opts=self.pipe_names))
+        if not hasattr(component, "__call__"):
+            msg = Errors.E003.format(component=repr(component), name=name)
+            if isinstance(component, basestring_) and component in self.factories:
+                msg += Errors.E135.format(name=name)
+            raise ValueError(msg)
         self.pipeline[self.pipe_names.index(name)] = (name, component)
 
     def rename_pipe(self, old_name, new_name):

spacy/tests/pipeline/test_pipe_methods.py

@@ -52,11 +52,13 @@ def test_get_pipe(nlp, name):
     assert nlp.get_pipe(name) == new_pipe
 
 
-@pytest.mark.parametrize("name,replacement", [("my_component", lambda doc: doc)])
-def test_replace_pipe(nlp, name, replacement):
+@pytest.mark.parametrize("name,replacement,not_callable", [("my_component", lambda doc: doc, {})])
+def test_replace_pipe(nlp, name, replacement, not_callable):
     with pytest.raises(ValueError):
         nlp.replace_pipe(name, new_pipe)
     nlp.add_pipe(new_pipe, name=name)
+    with pytest.raises(ValueError):
+        nlp.replace_pipe(name, not_callable)
     nlp.replace_pipe(name, replacement)
     assert nlp.get_pipe(name) != new_pipe
     assert nlp.get_pipe(name) == replacement