SNOW-857216: fix compatibility issue with sqlalchemy 1.4.49 (snowflakedb#423)

Author: sfc-gh-aling

Diff for: DESCRIPTION.md

@@ -11,7 +11,8 @@ Source code is also available at:
 
 - v1.4.8(TBD)
 
-  - Added opiton to create a temporary stage command.
+  - Added option to create a temporary stage command.
+  - Fixed a compatibility issue of regex expression with SQLAlchemy 1.4.49.
 
 - v1.4.7(Mar 22, 2023)
 

Diff for: src/snowflake/sqlalchemy/base.py

@@ -376,7 +376,14 @@ def visit_regexp_match_op_binary(self, binary, operator, **kw):
 
     def visit_regexp_replace_op_binary(self, binary, operator, **kw):
         string, pattern, flags = self._get_regexp_args(binary, kw)
-        replacement = self.process(binary.modifiers["replacement"], **kw)
+        try:
+            replacement = self.process(binary.modifiers["replacement"], **kw)
+        except KeyError:
+            # in sqlalchemy 1.4.49, the internal structure of the expression is changed
+            # that binary.modifiers doesn't have "replacement":
+            # https://docs.sqlalchemy.org/en/20/changelog/changelog_14.html#change-1.4.49
+            return f"REGEXP_REPLACE({string}, {pattern}{'' if flags is None else f', {flags}'})"
+
         if flags is None:
             return f"REGEXP_REPLACE({string}, {pattern}, {replacement})"
         else: