Merge "Apply SQL compilation to sqltext for column-level CHECK constraint"

3 files changed, 28 insertions, 1 deletions

diff --git a/doc/build/changelog/changelog_12.rst b/doc/build/changelog/changelog_12.rst
index 1d66adc8e..ad9e73160 100644
--- a/doc/build/changelog/changelog_12.rst
+++ b/doc/build/changelog/changelog_12.rst
@@ -13,6 +13,18 @@
 .. changelog::
     :version: 1.2.0b1
 
+    .. change:: 3957
+        :tags: bug, sql
+        :tickets: 3957
+
+        Fixed bug where a column-level :class:`.CheckConstraint` would fail
+        to compile the SQL expression using the underlying dialect compiler
+        as well as apply proper flags to generate literal values as
+        inline, in the case that the sqltext is a Core expression and
+        not just a plain string.   This was long-ago fixed for table-level
+        check constraints in 0.9 as part of :ticket:`2742`, which more commonly
+        feature Core SQL expressions as opposed to plain string expressions.
+
     .. change:: 3923
         :tags: bug, sql
         :tickets: 3923
diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 441502898..b18f90312 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -2602,7 +2602,9 @@ class DDLCompiler(Compiled):
             formatted_name = self.preparer.format_constraint(constraint)
             if formatted_name is not None:
                 text += "CONSTRAINT %s " % formatted_name
-        text += "CHECK (%s)" % constraint.sqltext
+        text += "CHECK (%s)" % self.sql_compiler.process(constraint.sqltext,
+                                                         include_table=False,
+                                                         literal_binds=True)
         text += self.define_constraint_deferrability(constraint)
         return text
 
diff --git a/test/sql/test_constraints.py b/test/sql/test_constraints.py
index aebbb4c30..3365b3cf0 100644
--- a/test/sql/test_constraints.py
+++ b/test/sql/test_constraints.py
@@ -1137,6 +1137,19 @@ class ConstraintCompilationTest(fixtures.TestBase, AssertsCompiledSQL):
             "ALTER TABLE tbl ADD CHECK (a > 5)"
         )
 
+    def test_render_check_constraint_inline_sql_literal(self):
+        t, t2 = self._constraint_create_fixture()
+
+        m = MetaData()
+        t = Table(
+            't', m,
+            Column('a', Integer, CheckConstraint(Column('a', Integer) > 5)))
+
+        self.assert_compile(
+            schema.CreateColumn(t.c.a),
+            "a INTEGER CHECK (a > 5)"
+        )
+
     def test_render_index_sql_literal(self):
         t, t2 = self._constraint_create_fixture()