Fix reflection of long expressions in postgresql

Fixed issue that prevented reflection of expression based indexes
with long expressions in PostgreSQL. The expression where erroneously
truncated to the identifier length (that's 63 bytes by default).

Fixes: #9615
Change-Id: I50727b0699e08fa25f10f3c94dcf8b79534bfb75

1 files changed, 22 insertions, 4 deletions

diff --git a/lib/sqlalchemy/testing/suite/test_reflection.py b/lib/sqlalchemy/testing/suite/test_reflection.py
index 8b7cb8cbc..5927df065 100644
--- a/lib/sqlalchemy/testing/suite/test_reflection.py
+++ b/lib/sqlalchemy/testing/suite/test_reflection.py
@@ -2397,7 +2397,8 @@ class ComponentReflectionTestExtra(ComparesIndexes, fixtures.TestBase):
         )
 
         Index("t_idx", func.lower(t.c.x), t.c.z, func.lower(t.c.y))
-
+        long_str = "long string " * 100
+        Index("t_idx_long", func.coalesce(t.c.x, long_str))
         Index("t_idx_2", t.c.x)
 
         metadata.create_all(connection)
@@ -2424,24 +2425,41 @@ class ComponentReflectionTestExtra(ComparesIndexes, fixtures.TestBase):
 
         completeIndex(expected[0])
 
-        class filtering_str(str):
+        class lower_index_str(str):
             def __eq__(self, other):
                 # test that lower and x or y are in the string
                 return "lower" in other and ("x" in other or "y" in other)
 
+        class coalesce_index_str(str):
+            def __eq__(self, other):
+                # test that coalesce and the string is in other
+                return "coalesce" in other.lower() and long_str in other
+
         if testing.requires.reflect_indexes_with_expressions.enabled:
             expr_index = {
                 "name": "t_idx",
                 "column_names": [None, "z", None],
                 "expressions": [
-                    filtering_str("lower(x)"),
+                    lower_index_str("lower(x)"),
                     "z",
-                    filtering_str("lower(y)"),
+                    lower_index_str("lower(y)"),
                 ],
                 "unique": False,
             }
             completeIndex(expr_index)
             expected.insert(0, expr_index)
+
+            expr_index_long = {
+                "name": "t_idx_long",
+                "column_names": [None],
+                "expressions": [
+                    coalesce_index_str(f"coalesce(x, '{long_str}')")
+                ],
+                "unique": False,
+            }
+            completeIndex(expr_index_long)
+            expected.append(expr_index_long)
+
             eq_(insp.get_indexes("t"), expected)
             m2 = MetaData()
             t2 = Table("t", m2, autoload_with=connection)