PYTHON-2253 raise client-side error when allowDiskUse is specified with MongoDB <= 3.2

Author: prashantmital

pymongo/collection.py

@@ -1442,7 +1442,8 @@ def find(self, *args, **kwargs):
             disk files to store data exceeding the system memory limit while
             processing a blocking sort operation. The option has no effect if
             MongoDB can satisfy the specified sort using an index, or if the
-            blocking sort requires less memory than the 100 MiB limit.
+            blocking sort requires less memory than the 100 MiB limit. This
+            option is only supported on MongoDB 4.4 and above.
 
         .. note:: There are a number of caveats to using
           :attr:`~pymongo.cursor.CursorType.EXHAUST` as cursor_type:

pymongo/cursor.py

@@ -441,7 +441,9 @@ def allow_disk_use(self, allow_disk_use):
         """Specifies whether MongoDB can use temporary disk files while
         processing a blocking sort operation.
 
-        Raises :exc:`TypeError` is `allow_disk_use` is not a boolean.
+        Raises :exc:`TypeError` if `allow_disk_use` is not a boolean.
+
+        .. note:: `allow_disk_use` requires server version **>= 4.4**
 
         :Parameters:
           - `allow_disk_use`: if True, MongoDB may use temporary

pymongo/message.py

@@ -283,8 +283,9 @@ def use_command(self, sock_info, exhaust):
                 'version of %d.' % (sock_info.max_wire_version,))
 
         if sock_info.max_wire_version < 4 and self.allow_disk_use is not None:
-            # Ignore allowDiskUse for MongoDB < 3.2.
-            self.allow_disk_use = None
+            raise ConfigurationError(
+                'Specifying allowDiskUse is unsupported with a max wire '
+                'version of %d.' % (sock_info.max_wire_version,))
 
         sock_info.validate_session(self.client, self.session)
 

test/crud/v2/find-allowdiskuse-clientError.json

@@ -0,0 +1,40 @@
+{
+  "runOn": [
+    {
+      "maxServerVersion": "3.0.99"
+    }
+  ],
+  "collection_name": "test_find_allowdiskuse_clienterror",
+  "tests": [
+    {
+      "description": "Find fails when allowDiskUse true is specified against pre 3.2 server",
+      "operations": [
+        {
+          "object": "collection",
+          "name": "find",
+          "arguments": {
+            "filter": {},
+            "allowDiskUse": true
+          },
+          "error": true
+        }
+      ],
+      "expectations": []
+    },
+    {
+      "description": "Find fails when allowDiskUse false is specified against pre 3.2 server",
+      "operations": [
+        {
+          "object": "collection",
+          "name": "find",
+          "arguments": {
+            "filter": {},
+            "allowDiskUse": false
+          },
+          "error": true
+        }
+      ],
+      "expectations": []
+    }
+  ]
+}

test/crud/v2/find-allowdiskuse-serverError.json

@@ -0,0 +1,61 @@
+{
+  "runOn": [
+    {
+      "minServerVersion": "3.2",
+      "maxServerVersion": "4.3.0"
+    }
+  ],
+  "collection_name": "test_find_allowdiskuse_servererror",
+  "tests": [
+    {
+      "description": "Find fails when allowDiskUse true is specified against pre 4.4 server (server-side error)",
+      "operations": [
+        {
+          "object": "collection",
+          "name": "find",
+          "arguments": {
+            "filter": {},
+            "allowDiskUse": true
+          },
+          "error": true
+        }
+      ],
+      "expectations": [
+        {
+          "command_started_event": {
+            "command": {
+              "find": "test_find_allowdiskuse_servererror",
+              "filter": {},
+              "allowDiskUse": true
+            }
+          }
+        }
+      ]
+    },
+    {
+      "description": "Find fails when allowDiskUse false is specified against pre 4.4 server (server-side error)",
+      "operations": [
+        {
+          "object": "collection",
+          "name": "find",
+          "arguments": {
+            "filter": {},
+            "allowDiskUse": false
+          },
+          "error": true
+        }
+      ],
+      "expectations": [
+        {
+          "command_started_event": {
+            "command": {
+              "find": "test_find_allowdiskuse_servererror",
+              "filter": {},
+              "allowDiskUse": false
+            }
+          }
+        }
+      ]
+    }
+  ]
+}