From 4d198a7e92f813fb9df2ade72fbeaf847284a7a0 Mon Sep 17 00:00:00 2001
From: Ines Montani <ines@ines.io>
Date: Tue, 9 Apr 2019 12:50:43 +0200
Subject: [PATCH] Ensure match pattern error isn't raised on empty errors
 (closes #3549)

---
 spacy/matcher/matcher.pyx                |  2 +-
 spacy/tests/regression/test_issue3549.py | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 spacy/tests/regression/test_issue3549.py

diff --git a/spacy/matcher/matcher.pyx b/spacy/matcher/matcher.pyx
index 37218ce0d..b58c0e072 100644
--- a/spacy/matcher/matcher.pyx
+++ b/spacy/matcher/matcher.pyx
@@ -105,7 +105,7 @@ cdef class Matcher:
                 raise ValueError(Errors.E012.format(key=key))
             if self.validator:
                 errors[i] = validate_json(pattern, self.validator)
-        if errors:
+        if any(err for err in errors.values()):
             raise MatchPatternError(key, errors)
         key = self._normalize_key(key)
         for pattern in patterns:
diff --git a/spacy/tests/regression/test_issue3549.py b/spacy/tests/regression/test_issue3549.py
new file mode 100644
index 000000000..3932bf19c
--- /dev/null
+++ b/spacy/tests/regression/test_issue3549.py
@@ -0,0 +1,15 @@
+# coding: utf8
+from __future__ import unicode_literals
+
+import pytest
+from spacy.matcher import Matcher
+from spacy.errors import MatchPatternError
+
+
+def test_issue3549(en_vocab):
+    """Test that match pattern validation doesn't raise on empty errors."""
+    matcher = Matcher(en_vocab, validate=True)
+    pattern = [{"LOWER": "hello"}, {"LOWER": "world"}]
+    matcher.add("GOOD", None, pattern)
+    with pytest.raises(MatchPatternError):
+        matcher.add("BAD", None, [{"X": "Y"}])