Enhance FK reflection with Unicode names (#225)

Accommodate differences in quoting between CockroachDB
and PostgreSQL

Also bump cryptography version as per #223

CHANGES.md

@@ -3,6 +3,7 @@ Unreleased
 
 - Implement reflection for array types (#213)
 - Fix get_multi_columns() to support multiple table names in filter_array (#220)
+- Enhance foreign key reflection to accommodate quoting differences with PostgreSQL
 
 # Version 2.0.1
 April 14, 2023

dev-requirements.txt

@@ -6,7 +6,7 @@ cffi==1.15.1
     # via cryptography
 charset-normalizer==3.2.0
     # via requests
-cryptography==41.0.3
+cryptography==41.0.4
     # via secretstorage
 distlib==0.3.7
     # via virtualenv

sqlalchemy_cockroachdb/base.py

@@ -2,6 +2,7 @@
 import re
 import threading
 from sqlalchemy import text
+from sqlalchemy import util
 from sqlalchemy.dialects.postgresql.base import PGDialect
 from sqlalchemy.dialects.postgresql import ARRAY
 from sqlalchemy.dialects.postgresql import INET
@@ -357,6 +358,24 @@ def get_foreign_keys_v1(self, conn, table_name, schema=None, **kw):
                 fkeys.append(fkey_d)
         return fkeys
 
+    @util.memoized_property
+    def _fk_regex_pattern(self):
+        # optionally quoted token
+        qtoken = r'(?:"[^"]+"|[\w]+?)'
+
+        # https://www.postgresql.org/docs/current/static/sql-createtable.html
+        return re.compile(
+            r"FOREIGN KEY \((.*?)\) "
+            rf"REFERENCES (?:({qtoken})\.)?({qtoken})\(((?:{qtoken}(?: *, *)?)+)\)"  # noqa: E501
+            r"[\s]?(MATCH (FULL|PARTIAL|SIMPLE)+)?"
+            r"[\s]?(ON UPDATE "
+            r"(CASCADE|RESTRICT|NO ACTION|SET NULL|SET DEFAULT)+)?"
+            r"[\s]?(ON DELETE "
+            r"(CASCADE|RESTRICT|NO ACTION|SET NULL|SET DEFAULT)+)?"
+            r"[\s]?(DEFERRABLE|NOT DEFERRABLE)?"
+            r"[\s]?(INITIALLY (DEFERRED|IMMEDIATE)+)?"
+        )
+
     def get_foreign_keys(
         self, connection, table_name, schema=None, postgresql_ignore_search_path=False, **kw
     ):
@@ -390,16 +409,7 @@ def get_foreign_keys(
           ORDER BY 1
         """
         # http://www.postgresql.org/docs/9.0/static/sql-createtable.html
-        FK_REGEX = re.compile(
-            r"FOREIGN KEY \((.*?)\) REFERENCES (?:(.*?)\.)?(.*?)[\s]?\((.*?)\)"
-            r"[\s]?(MATCH (FULL|PARTIAL|SIMPLE)+)?"
-            r"[\s]?(ON UPDATE "
-            r"(CASCADE|RESTRICT|NO ACTION|SET NULL|SET DEFAULT)+)?"
-            r"[\s]?(ON DELETE "
-            r"(CASCADE|RESTRICT|NO ACTION|SET NULL|SET DEFAULT)+)?"
-            r"[\s]?(DEFERRABLE|NOT DEFERRABLE)?"
-            r"[\s]?(INITIALLY (DEFERRED|IMMEDIATE)+)?"
-        )
+        FK_REGEX = self._fk_regex_pattern
 
         t = sql.text(FK_SQL).columns(conname=sqltypes.Unicode, condef=sqltypes.Unicode)
         c = connection.execute(t, {"table": table_oid})