[FIX] util/pg: drop indexes when removing constraints

If a constraint with the same name was found. Attempt as well to drop
any existing index with the same name. Otherwise we may leave behind
constraints implemented as unique indexes.

See odoo/upgrade#8318

closes #310

Signed-off-by: Christophe Simonis (chs) <chs@odoo.com>

Author: aj-fuentes

src/util/pg.py

@@ -795,15 +795,17 @@ def remove_constraint(cr, table, name, cascade=False, warn=True):
     """
     _validate_table(table)
     log = _logger.warning if warn else _logger.info
-    cascade = "CASCADE" if cascade else ""
-    cr.execute('ALTER TABLE "{}" DROP CONSTRAINT IF EXISTS "{}" {}'.format(table, name, cascade))
+    cascade = SQLStr("CASCADE" if cascade else "")
+    cr.execute(format_query(cr, "ALTER TABLE {} DROP CONSTRAINT IF EXISTS {} {}", table, name, cascade))
     # Exceptionally remove Odoo records, even if we are in PG land on this file. This is somehow
     # valid because ir.model.constraint are ORM low-level objects that relate directly to table
     # constraints.
     cr.execute("DELETE FROM ir_model_constraint WHERE name = %s RETURNING id", [name])
     if cr.rowcount:
         ids = tuple(c for (c,) in cr.fetchall())
         cr.execute("DELETE FROM ir_model_data WHERE model = 'ir.model.constraint' AND res_id IN %s", [ids])
+        # The constraint was found remove any index with same name
+        cr.execute(format_query(cr, "DROP INDEX IF EXISTS {}", name))
         return True
     if name.startswith(table + "_"):
         log("%r not found in ir_model_constraint, table=%r", name, table)