From: pg3-ivan <ivan.melnychuk@pg3.ch>
Date: Fri, 25 Aug 2017 14:02:31 +0000 (-0400)
Subject: Don't compare scale if Numeric has no precision
X-Git-Tag: rel_0_9_6~15
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7fb22863a80a5bad8c906e4655c502953cb3490c;p=thirdparty%2Fsqlalchemy%2Falembic.git

Don't compare scale if Numeric has no precision

Fixed bug where comparison of ``Numeric`` types would produce
a difference if the Python-side ``Numeric`` inadvertently specified
a non-None "scale" with a "precision" of None, even though this ``Numeric``
type will pass over the "scale" argument when rendering. Pull request
courtesy Ivan Mmelnychuk.

Change-Id: I0a676e01579fdf6802bf53ea7f9238003da98847
Pull-request: https://bitbucket.org/zzzeek/alembic/pull-requests/70
---

diff --git a/alembic/ddl/impl.py b/alembic/ddl/impl.py
index 39558ab4..ec170fd0 100644
--- a/alembic/ddl/impl.py
+++ b/alembic/ddl/impl.py
@@ -333,15 +333,14 @@ def _string_compare(t1, t2):
 
 
 def _numeric_compare(t1, t2):
-    return \
-        (
-            t1.precision is not None and
-            t1.precision != t2.precision
-        ) or \
-        (
-            t1.scale is not None and
-            t1.scale != t2.scale
-        )
+    return (
+        t1.precision is not None and
+        t1.precision != t2.precision
+    ) or (
+        t1.precision is not None and
+        t1.scale is not None and
+        t1.scale != t2.scale
+    )
 
 
 def _integer_compare(t1, t2):
diff --git a/docs/build/unreleased/numeric_comparison.rst b/docs/build/unreleased/numeric_comparison.rst
new file mode 100644
index 00000000..3e2edfaf
--- /dev/null
+++ b/docs/build/unreleased/numeric_comparison.rst
@@ -0,0 +1,9 @@
+.. change::
+    :tags: bug, autogenerate
+    :pullreq: bitbucket:70
+
+    Fixed bug where comparison of ``Numeric`` types would produce
+    a difference if the Python-side ``Numeric`` inadvertently specified
+    a non-None "scale" with a "precision" of None, even though this ``Numeric``
+    type will pass over the "scale" argument when rendering. Pull request
+    courtesy Ivan Mmelnychuk.
diff --git a/tests/test_autogen_diffs.py b/tests/test_autogen_diffs.py
index e01d631a..db77d745 100644
--- a/tests/test_autogen_diffs.py
+++ b/tests/test_autogen_diffs.py
@@ -638,6 +638,13 @@ class CompareTypeSpecificityTest(TestBase):
         is_(impl.compare_type(Column('x', t3), Column('x', t2)), True)
         is_(impl.compare_type(Column('x', t3), Column('x', t4)), True)
 
+    def test_numeric_noprecision(self):
+        t1 = Numeric()
+        t2 = Numeric(scale=5)
+
+        impl = self._fixture()
+        is_(impl.compare_type(Column('x', t1), Column('x', t2)), False)
+
     def test_integer(self):
         t1 = Integer()
         t2 = SmallInteger()