While parsing for check constraints, ignore newline characters in the check condition

Fixed bug where PostgreSQL reflection of CHECK constraints would fail to
parse the constraint if the SQL text contained newline characters. The
regular expression has been adjusted to accommodate for this case. Pull
request courtesy Eric Borczuk.

Fixes: #5170
Closes: #5172
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/5172
Pull-request-sha: 5701b7f09f723b727bbee95d19d107d6cc1d7717

Change-Id: If727e9140b645e8b685c3476fb0fa4417c1e6526

1 files changed, 8 insertions, 2 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index 0a442f256..bfe3812be 100644
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -3488,12 +3488,18 @@ class PGDialect(default.DefaultDialect):
             # "CHECK (((a = 1) OR ((a > 2) AND (a < 5))))"
             # "CHECK (((a > 1) AND (a < 5))) NOT VALID"
             # "CHECK (some_boolean_function(a))"
-            m = re.match(r"^CHECK *\((.+)\)( NOT VALID)?$", src)
+            # "CHECK (((a\n < 1)\n OR\n (a\n >= 5))\n)"
+
+            m = re.match(
+                r"^CHECK *\((.+)\)( NOT VALID)?$", src, flags=re.DOTALL
+            )
             if not m:
                 util.warn("Could not parse CHECK constraint text: %r" % src)
                 sqltext = ""
             else:
-                sqltext = re.sub(r"^\((.+)\)$", r"\1", m.group(1))
+                sqltext = re.compile(
+                    r"^[\s\n]*\((.+)\)[\s\n]*$", flags=re.DOTALL
+                ).sub(r"\1", m.group(1))
             entry = {"name": name, "sqltext": sqltext}
             if m and m.group(2):
                 entry["dialect_options"] = {"not_valid": True}