StringStore now actually cleaned

Do not lose docs in ref tracking

spacy/language.py

@@ -558,6 +558,7 @@ class Language(object):
                 old_refs.add(doc)
                 nr_seen += 1
             elif len(old_refs) == 0:
+                old_refs, recent_refs = recent_refs, old_refs
                 self.vocab.strings._cleanup_stale_strings()
                 nr_seen = 0
         # Last batch can be not garbage collected and we cannot know it — last

spacy/strings.pyx

@@ -260,6 +260,9 @@ cdef class StringStore:
             if self.hits.count(key) != 0:
                 tmp.push_back(key)
 
+        strings = list(self)
+        self._reset_and_load(strings)
+
         self.keys.swap(tmp)
         self.hits.clear()
 

spacy/tests/regression/test_issue1506.py

@@ -1,6 +1,8 @@
 # coding: utf8
 from __future__ import unicode_literals
 
+import gc
+
 from ...lang.en import English
 
 
@@ -11,12 +13,26 @@ def test_issue1506():
         for _ in range(10001):
             yield "It's sentence produced by that bug."
 
+        yield "Oh snap."
+
         for _ in range(10001):
             yield "I erase lemmas."
 
         for _ in range(10001):
             yield "It's sentence produced by that bug."
 
-    for d in nlp.pipe(string_generator()):
-        for t in d:
-            str(t.lemma_)
+        for _ in range(10001):
+            yield "It's sentence produced by that bug."
+
+    anchor = None
+    remember = None
+    for i, d in enumerate(nlp.pipe(string_generator())):
+        if i == 9999:
+            anchor = d
+        elif 10001 == i:
+            remember = d
+        elif i == 10002:
+            del anchor
+            gc.collect()
+
+    assert remember.text == 'Oh snap.'