From bec8db91e6b8aa8c64a24ac6562c9a8aaf639a13 Mon Sep 17 00:00:00 2001
From: Ines Montani <ines@ines.io>
Date: Fri, 15 Mar 2019 16:38:44 +0100
Subject: [PATCH] Add actual deprecation warning for n_threads (resolves #3410)

---
 spacy/errors.py                          |  4 ++++
 spacy/language.py                        |  2 ++
 spacy/matcher/matcher.pyx                |  4 +++-
 spacy/matcher/phrasematcher.pyx          |  2 ++
 spacy/tests/regression/test_issue3410.py | 21 +++++++++++++++++++++
 spacy/tokenizer.pyx                      |  2 ++
 6 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100644 spacy/tests/regression/test_issue3410.py

diff --git a/spacy/errors.py b/spacy/errors.py
index 0ccff4c75..1fca7060b 100644
--- a/spacy/errors.py
+++ b/spacy/errors.py
@@ -76,6 +76,10 @@ class Warnings(object):
     W015 = ("As of v2.1.0, the use of keyword arguments to exclude fields from "
             "being serialized or deserialized is deprecated. Please use the "
             "`exclude` argument instead. For example: exclude=['{arg}'].")
+    W016 = ("The keyword argument `n_threads` on the is now deprecated, as "
+            "the v2.x models cannot release the global interpreter lock. "
+            "Future versions may introduce a `n_process` argument for "
+            "parallel inference via multiprocessing.")
 
 
 @add_codes
diff --git a/spacy/language.py b/spacy/language.py
index 48ba17218..ec365e12b 100644
--- a/spacy/language.py
+++ b/spacy/language.py
@@ -666,6 +666,8 @@ class Language(object):
 
         DOCS: https://spacy.io/api/language#pipe
         """
+        if n_threads != -1:
+            deprecation_warning(Warnings.W016)
         if as_tuples:
             text_context1, text_context2 = itertools.tee(texts)
             texts = (tc[0] for tc in text_context1)
diff --git a/spacy/matcher/matcher.pyx b/spacy/matcher/matcher.pyx
index 7abe42843..37218ce0d 100644
--- a/spacy/matcher/matcher.pyx
+++ b/spacy/matcher/matcher.pyx
@@ -19,7 +19,7 @@ from ..attrs cimport ID, attr_id_t, NULL_ATTR, ORTH
 
 from ._schemas import TOKEN_PATTERN_SCHEMA
 from ..util import get_json_validator, validate_json
-from ..errors import Errors, MatchPatternError
+from ..errors import Errors, MatchPatternError, Warnings, deprecation_warning
 from ..strings import get_string_id
 from ..attrs import IDS
 
@@ -160,6 +160,8 @@ cdef class Matcher:
         batch_size (int): Number of documents to accumulate into a working set.
         YIELDS (Doc): Documents, in order.
         """
+        if n_threads != -1:
+            deprecation_warning(Warnings.W016)
         for doc in docs:
             self(doc)
             yield doc
diff --git a/spacy/matcher/phrasematcher.pyx b/spacy/matcher/phrasematcher.pyx
index ddf6e8cce..22ce8831a 100644
--- a/spacy/matcher/phrasematcher.pyx
+++ b/spacy/matcher/phrasematcher.pyx
@@ -182,6 +182,8 @@ cdef class PhraseMatcher:
 
         DOCS: https://spacy.io/api/phrasematcher#pipe
         """
+        if n_threads != -1:
+            deprecation_warning(Warnings.W016)
         if as_tuples:
             for doc, context in stream:
                 matches = self(doc)
diff --git a/spacy/tests/regression/test_issue3410.py b/spacy/tests/regression/test_issue3410.py
new file mode 100644
index 000000000..5d2ac5ba3
--- /dev/null
+++ b/spacy/tests/regression/test_issue3410.py
@@ -0,0 +1,21 @@
+# coding: utf8
+from __future__ import unicode_literals
+
+import pytest
+from spacy.lang.en import English
+from spacy.matcher import Matcher, PhraseMatcher
+
+
+def test_issue3410():
+    texts = ["Hello world", "This is a test"]
+    nlp = English()
+    matcher = Matcher(nlp.vocab)
+    phrasematcher = PhraseMatcher(nlp.vocab)
+    with pytest.deprecated_call():
+        docs = list(nlp.pipe(texts, n_threads=4))
+    with pytest.deprecated_call():
+        docs = list(nlp.tokenizer.pipe(texts, n_threads=4))
+    with pytest.deprecated_call():
+        list(matcher.pipe(docs, n_threads=4))
+    with pytest.deprecated_call():
+        list(phrasematcher.pipe(docs, n_threads=4))
diff --git a/spacy/tokenizer.pyx b/spacy/tokenizer.pyx
index bec509624..86c2d6ad3 100644
--- a/spacy/tokenizer.pyx
+++ b/spacy/tokenizer.pyx
@@ -134,6 +134,8 @@ cdef class Tokenizer:
 
         DOCS: https://spacy.io/api/tokenizer#pipe
         """
+        if n_threads != -1:
+            deprecation_warning(Warnings.W016)
         for text in texts:
             yield self(text)