Deprecate DataAccelerationReport.get

Tableau deprecated data acceleration in Tableau Server 2022.1 and
retired it, with its REST API methods, in Tableau Server 2026.2. It was
never available on Tableau Cloud. Emit a DeprecationWarning from get so
callers are told the method will be removed in a future release.

Related to #734

Co-Authored-By: Claude Code <noreply@anthropic.com>

Author: jacalata

tableauserverclient/server/endpoint/data_acceleration_report_endpoint.py

@@ -1,4 +1,5 @@
 import logging
+import warnings
 
 from .default_permissions_endpoint import _DefaultPermissionsEndpoint
 from .endpoint import api, Endpoint
@@ -21,6 +22,38 @@ def baseurl(self):
 
     @api(version="3.8")
     def get(self, req_options=None):
+        """
+        Gets the data acceleration report for the current site, which compares
+        page load times for sheets before and after data acceleration.
+
+        Deprecated: this method will be removed in a future release of this
+        library. Tableau retired data acceleration and its REST API methods
+        in Tableau Server 2026.2, and it was never available on Tableau Cloud.
+
+        REST API: https://help.tableau.com/current/api/rest_api/en-us/REST/rest_api_ref_site.htm#get_data_acceleration_report
+
+        Parameters
+        ----------
+        req_options : RequestOptions, optional
+            Options to pass to the request.
+
+        Returns
+        -------
+        DataAccelerationReportItem
+            The report, with one comparison record per accelerated sheet.
+
+        Warnings
+        --------
+        This method is deprecated. Tableau Cloud and Tableau Server 2026.2 and
+        later return an error for this request.
+        """
+        warnings.warn(
+            "DataAccelerationReport.get is deprecated and will be removed. Tableau retired data acceleration "
+            "in Tableau Server 2026.2.",
+            DeprecationWarning,
+            # 3, not 2: the @api wrapper adds a frame, and the warning should point at the caller.
+            stacklevel=3,
+        )
         logger.info("Querying data acceleration report")
         url = self.baseurl
         server_response = self.get_request(url, req_options)

test/test_data_acceleration_report.py

@@ -26,8 +26,10 @@ def test_get_data_acceleration_report(server):
     response_xml = GET_XML.read_text()
     with requests_mock.mock() as m:
         m.get(server.data_acceleration_report.baseurl, text=response_xml)
-        data_acceleration_report = server.data_acceleration_report.get()
+        with pytest.warns(DeprecationWarning, match="deprecated and will be removed") as record:
+            data_acceleration_report = server.data_acceleration_report.get()
 
+    assert record[0].filename == __file__
     assert 2 == len(data_acceleration_report.comparison_records)
 
     assert "site-1" == data_acceleration_report.comparison_records[0].site