From 93ef9634e77f3f92e384f9568c88d9828818a15b Mon Sep 17 00:00:00 2001
From: Ofer Koren <koreno@gmail.com>
Date: Wed, 25 Oct 2023 22:01:40 +0300
Subject: [PATCH] Raise appropriate exceptions for condition failures (#1076)

---
 pynamodb/connection/base.py | 10 ++++++++--
 pynamodb/exceptions.py      | 14 ++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/pynamodb/connection/base.py b/pynamodb/connection/base.py
index 975b02e8..e5a14200 100644
--- a/pynamodb/connection/base.py
+++ b/pynamodb/connection/base.py
@@ -1048,7 +1048,10 @@ def update_item(
         try:
             return self.dispatch(UPDATE_ITEM, operation_kwargs, settings)
         except BOTOCORE_EXCEPTIONS as e:
-            raise UpdateError("Failed to update item: {}".format(e), e)
+            exc = UpdateError("Failed to update item: {}".format(e), e)
+            if exc.cause_response_code == "ConditionalCheckFailedException":
+                exc.__class__ = ConditionFailedUpdate
+            raise exc
 
     def put_item(
         self,
@@ -1079,7 +1082,10 @@ def put_item(
         try:
             return self.dispatch(PUT_ITEM, operation_kwargs, settings)
         except BOTOCORE_EXCEPTIONS as e:
-            raise PutError("Failed to put item: {}".format(e), e)
+            exc = PutError("Failed to put item: {}".format(e), e)
+            if exc.cause_response_code == "ConditionalCheckFailedException":
+                exc.__class__ = ConditionFailedPut
+            raise exc
 
     def _get_transact_operation_kwargs(
         self,
diff --git a/pynamodb/exceptions.py b/pynamodb/exceptions.py
index 39dd5437..c252f3ad 100644
--- a/pynamodb/exceptions.py
+++ b/pynamodb/exceptions.py
@@ -84,6 +84,13 @@ class PutError(PynamoDBConnectionError):
     msg = "Error putting item"
 
 
+class ConditionFailedPut(PutError):
+    """
+    Raised when an item fails to be created due to condition
+    """
+    msg = "Condition failed while putting item"
+
+
 class UpdateError(PynamoDBConnectionError):
     """
     Raised when an item fails to be updated
@@ -91,6 +98,13 @@ class UpdateError(PynamoDBConnectionError):
     msg = "Error updating item"
 
 
+class ConditionFailedUpdate(UpdateError):
+    """
+    Raised when an item fails to be updated due to condition
+    """
+    msg = "Condition failed while updating item"
+
+
 class GetError(PynamoDBConnectionError):
     """
     Raised when an item fails to be retrieved