From 56d408c5b951a014f87e80e5233312731dad4753 Mon Sep 17 00:00:00 2001
From: Randy Syring <randy@thesyrings.us>
Date: Tue, 26 Mar 2019 15:50:31 -0400
Subject: [PATCH] remove external dependency for parsing SA version

---
 flask_sqlalchemy/utils.py | 16 +++++++++++++++-
 tests/test_utils.py       |  4 ++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/flask_sqlalchemy/utils.py b/flask_sqlalchemy/utils.py
index 30619b07..52ea94e0 100644
--- a/flask_sqlalchemy/utils.py
+++ b/flask_sqlalchemy/utils.py
@@ -1,8 +1,22 @@
 
-from pkg_resources import parse_version
 import sqlalchemy
 
 
+def parse_version(v):
+    """
+        Take a string version and conver it to a tuple (for easier comparison), e.g.:
+
+            "1.2.3" --> (1, 2, 3)
+            "1.2" --> (1, 2, 0)
+            "1" --> (1, 0, 0)
+    """
+    parts = v.split(".")
+    # Pad the list to make sure there is three elements so that we get major, minor, point
+    # comparisons that default to "0" if not given.  I.e. "1.2" --> (1, 2, 0)
+    parts = (parts + 3 * ['0'])[:3]
+    return tuple(int(x) for x in parts)
+
+
 def sqlalchemy_version(op, val):
     sa_ver = parse_version(sqlalchemy.__version__)
     target_ver = parse_version(val)
diff --git a/tests/test_utils.py b/tests/test_utils.py
index e6dddaaa..4c673f9a 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -4,6 +4,10 @@
 
 
 class TestSQLAlchemyVersion:
+    def test_parse_version(self):
+        assert utils.parse_version('1.2.3') == (1, 2, 3)
+        assert utils.parse_version('1.2') == (1, 2, 0)
+        assert utils.parse_version('1') == (1, 0, 0)
 
     @mock.patch.object(utils, 'sqlalchemy')
     def test_sqlalchemy_version(self, m_sqlalchemy):