fix(explore): Pass sort param for group-by explore Slack unfurls

When an Explore link with groupBy is unfurled in Slack, the unfurl sets
topEvents=5 but omits the sort parameter. Without it, the timeseries
endpoint returns whichever groups it defaults to rather than the top
groups matching what Explore shows.

Now copies the aggregateSort URL param (Explore's name) as sort (the
API name), and defaults to descending by the charted yAxis when no
explicit sort is present — matching the frontend's behavior.

Fixes DAIN-1490
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: DominikB2014

src/sentry/integrations/slack/unfurl/explore.py

@@ -127,6 +127,10 @@ def _unfurl_explore(
         style = ChartType.SLACK_EXPLORE_LINE
         if group_bys:
             params.setlist("topEvents", [str(TOP_N)])
+            if not params.getlist("sort"):
+                # Default to descending by the first yAxis, matching Explore's
+                # defaultAggregateSortBys behavior
+                params.setlist("sort", [f"-{y_axes[0]}"])
 
         if not params.get("statsPeriod") and not params.get("start"):
             params["statsPeriod"] = DEFAULT_PERIOD
@@ -227,6 +231,12 @@ def map_explore_query_args(url: str, args: Mapping[str, str | None]) -> Mapping[
         if values:
             query.setlist(param, values)
 
+    # Explore stores the aggregate sort as "aggregateSort" in the URL;
+    # the events-timeseries endpoint expects it as "sort".
+    aggregate_sort = raw_query.getlist("aggregateSort")
+    if aggregate_sort:
+        query.setlist("sort", aggregate_sort)
+
     return dict(**args, query=query, chart_type=chart_type, dataset=explore_dataset)
 
 

tests/sentry/integrations/slack/test_unfurl.py

@@ -1576,6 +1576,37 @@ def test_unfurl_explore_with_groupby(
         assert len(mock_generate_chart.mock_calls) == 1
         assert mock_generate_chart.call_args[0][0] == ChartType.SLACK_EXPLORE_LINE
 
+        # Verify sort is passed to the timeseries API for correct top events
+        api_params = mock_client_get.call_args[1]["params"]
+        assert api_params.getlist("sort") == ["-avg(span.duration)"]
+
+    @patch(
+        "sentry.integrations.slack.unfurl.explore.client.get",
+    )
+    @patch("sentry.charts.backend.generate_chart", return_value="chart-url")
+    def test_unfurl_explore_with_groupby_explicit_sort(
+        self, mock_generate_chart: MagicMock, mock_client_get: MagicMock
+    ) -> None:
+        mock_client_get.return_value = MagicMock(data=self._build_mock_timeseries_response())
+        url = f"https://sentry.io/organizations/{self.organization.slug}/explore/traces/?aggregateField=%7B%22groupBy%22%3A%22span.op%22%7D&aggregateField=%7B%22yAxes%22%3A%5B%22avg(span.duration)%22%5D%7D&aggregateSort=span.op&project={self.project.id}&statsPeriod=24h"
+        link_type, args = match_link(url)
+
+        if not args or not link_type:
+            raise AssertionError("Missing link_type/args")
+
+        links = [
+            UnfurlableUrl(url=url, args=args),
+        ]
+
+        with self.feature(["organizations:data-browsing-widget-unfurl"]):
+            unfurls = link_handlers[link_type].fn(self.integration, links, self.user)
+
+        assert len(unfurls) == 1
+
+        # Verify explicit aggregateSort from the URL is used instead of the default
+        api_params = mock_client_get.call_args[1]["params"]
+        assert api_params.getlist("sort") == ["span.op"]
+
     @patch(
         "sentry.integrations.slack.unfurl.explore.client.get",
     )