Fix port traffic wall blank chart when enabling baseline compare.

Set uPlot data before toggling baseline series, keep previous compare data while refetching, and resize after legend layout changes.

Co-authored-by: Cursor <cursoragent@cursor.com>

web/src/pages/network/PortTrafficPage.tsx

@@ -1,5 +1,5 @@
 import { useEffect, useMemo, useState } from "react";
-import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+import { useMutation, useQuery, useQueryClient, keepPreviousData } from "@tanstack/react-query";
 import {
   collectPortTrafficNow,
   createPortTrafficTask,
@@ -17,13 +17,14 @@ import {
 import { queryKeys } from "../../constants/queryKeys";
 import { useI18n } from "../../i18n";
 import { useToast } from "../../hooks/useToast";
-import type { CliTargetItem, PortTrafficDiscoverPort, PortTrafficTargetIn } from "../../types";
+import type { CliTargetItem, PortTrafficDiscoverPort, PortTrafficSamplePoint, PortTrafficTargetIn } from "../../types";
 import { pageCount } from "../../utils/display";
 import { formatSystemTime } from "../../utils/time";
 import { PortTrafficWall } from "./PortTrafficWall";
 
 const POLL_MS = 5000;
 const TARGET_PAGE_SIZE = 20;
+const EMPTY_COMPARE_POINTS: PortTrafficSamplePoint[] = [];
 
 type PortPick = PortTrafficTargetIn & { key: string };
 type BaselineMode = "off" | "shift" | "day" | "week" | "custom";
@@ -136,12 +137,19 @@ export function PortTrafficPage() {
       }),
     enabled: view === "wall" && Boolean(wallTargetId),
     staleTime: 1000,
+    placeholderData: keepPreviousData,
     refetchInterval: (q) => {
       const n = q.state.data?.current?.length ?? 0;
       return n === 0 ? 2500 : POLL_MS;
     },
   });
 
+  const wallPoints = compareQuery.data?.current ?? EMPTY_COMPARE_POINTS;
+  const wallBaselinePoints =
+    baseline === "off" && !mapBaselineTargetId
+      ? EMPTY_COMPARE_POINTS
+      : (compareQuery.data?.baseline ?? EMPTY_COMPARE_POINTS);
+
   const invalidateAll = () => {
     void queryClient.invalidateQueries({ queryKey: queryKeys.portTrafficTasksAll });
     void queryClient.invalidateQueries({ queryKey: queryKeys.portTrafficDashboard });
@@ -788,12 +796,8 @@ export function PortTrafficPage() {
           ) : null}
           <PortTrafficWall
             target={selectedWallTarget}
-            points={compareQuery.data?.current || []}
+            points={wallPoints}
-            baselinePoints={
+            baselinePoints={wallBaselinePoints}
-              baseline === "off" && !mapBaselineTargetId
-                ? []
-                : compareQuery.data?.baseline || []
-            }
             rangeLabel={`${rangeHours}h${
               baseline === "off"
                 ? ""

web/src/pages/network/PortTrafficWall.tsx

@@ -65,6 +65,8 @@ function chartSize(el: HTMLElement): { width: number; height: number } {
   return { width, height };
 }
 
+const EMPTY_POINTS: PortTrafficSamplePoint[] = [];
+
 type Props = {
   target: PortTrafficTarget | null;
   points: PortTrafficSamplePoint[];
@@ -77,7 +79,7 @@ type Props = {
 export function PortTrafficWall({
   target,
   points,
-  baselinePoints = [],
+  baselinePoints = EMPTY_POINTS,
   rangeLabel,
   loading,
   hint,
@@ -287,11 +289,25 @@ export function PortTrafficWall({
   useEffect(() => {
     const plot = plotRef.current;
     if (!plot) return;
+    // Always setData with resetScales; toggling series.show before setData can leave
+    // uPlot stuck on a blank [0,1] y-range until a later update.
+    const data = toAlignedSeries(points, baselinePoints);
     const showBaseline = baselinePoints.length > 0;
-    plot.setSeries(3, { show: showBaseline });
+    plot.setData(data, true);
-    plot.setSeries(4, { show: showBaseline });
+    const s3 = Boolean(plot.series[3]?.show);
-    plot.setData(toAlignedSeries(points, baselinePoints));
+    const s4 = Boolean(plot.series[4]?.show);
-    if (mountRef.current) plot.setSize(chartSize(mountRef.current));
+    if (s3 !== showBaseline || s4 !== showBaseline) {
+      plot.setSeries(3, { show: showBaseline }, false);
+      plot.setSeries(4, { show: showBaseline }, false);
+    }
+    const el = mountRef.current;
+    if (el) {
+      // Legend show/hide changes layout; size after paint.
+      requestAnimationFrame(() => {
+        if (!plotRef.current || !mountRef.current) return;
+        plotRef.current.setSize(chartSize(mountRef.current));
+      });
+    }
   }, [points, baselinePoints]);
 
   const empty = points.length === 0 && baselinePoints.length === 0;