Make all Span attrs writable (#8062)

Also allow `Span` string properties `label_` and `kb_id_` to be writable
following #6696.

spacy/errors.py

@@ -375,21 +375,10 @@ class Errors:
     E125 = ("Unexpected value: {value}")
     E126 = ("Unexpected matcher predicate: '{bad}'. Expected one of: {good}. "
             "This is likely a bug in spaCy, so feel free to open an issue.")
-    E129 = ("Cannot write the label of an existing Span object because a Span "
-            "is a read-only view of the underlying Token objects stored in the "
-            "Doc. Instead, create a new Span object and specify the `label` "
-            "keyword argument, for example:\nfrom spacy.tokens import Span\n"
-            "span = Span(doc, start={start}, end={end}, label='{label}')")
     E130 = ("You are running a narrow unicode build, which is incompatible "
             "with spacy >= 2.1.0. To fix this, reinstall Python and use a wide "
             "unicode build instead. You can also rebuild Python and set the "
             "`--enable-unicode=ucs4 flag`.")
-    E131 = ("Cannot write the kb_id of an existing Span object because a Span "
-            "is a read-only view of the underlying Token objects stored in "
-            "the Doc. Instead, create a new Span object and specify the "
-            "`kb_id` keyword argument, for example:\nfrom spacy.tokens "
-            "import Span\nspan = Span(doc, start={start}, end={end}, "
-            "label='{label}', kb_id='{kb_id}')")
     E132 = ("The vectors for entities and probabilities for alias '{alias}' "
             "should have equal length, but found {entities_length} and "
             "{probabilities_length} respectively.")

spacy/tests/doc/test_span.py

@@ -266,16 +266,10 @@ def test_span_string_label_kb_id(doc):
     assert span.kb_id == doc.vocab.strings["Q342"]
 
 
-def test_span_label_readonly(doc):
+def test_span_attrs_writable(doc):
     span = Span(doc, 0, 1)
-    with pytest.raises(NotImplementedError):
+    span.label_ = "label"
-        span.label_ = "hello"
+    span.kb_id_ = "kb_id"
-
-
-def test_span_kb_id_readonly(doc):
-    span = Span(doc, 0, 1)
-    with pytest.raises(NotImplementedError):
-        span.kb_id_ = "Q342"
 
 
 def test_span_ents_property(doc):

spacy/tokens/span.pyx

@@ -740,7 +740,7 @@ cdef class Span:
         def __get__(self):
             return self.root.ent_id_
 
-        def __set__(self, hash_t key):
+        def __set__(self, unicode key):
             raise NotImplementedError(Errors.E200.format(attr="ent_id_"))
 
     @property
@@ -762,9 +762,7 @@ cdef class Span:
             return self.doc.vocab.strings[self.label]
 
         def __set__(self, unicode label_):
-            if not label_:
+            self.label = self.doc.vocab.strings.add(label_)
-                label_ = ''
-            raise NotImplementedError(Errors.E129.format(start=self.start, end=self.end, label=label_))
 
     property kb_id_:
         """RETURNS (str): The named entity's KB ID."""
@@ -772,13 +770,7 @@ cdef class Span:
             return self.doc.vocab.strings[self.kb_id]
 
         def __set__(self, unicode kb_id_):
-            if not kb_id_:
+            self.kb_id = self.doc.vocab.strings.add(kb_id_)
-                kb_id_ = ''
-            current_label = self.label_
-            if not current_label:
-                current_label = ''
-            raise NotImplementedError(Errors.E131.format(start=self.start, end=self.end,
-                                                         label=current_label, kb_id=kb_id_))
 
 
 cdef int _count_words_to_root(const TokenC* token, int sent_length) except -1: