Harden MapLibre style readiness

frontend/README.md

@@ -162,6 +162,7 @@ React + TypeScript + MapLibre foundation for project/area/dataset workflow.
 - The strip summarizes existing connected state for project, AOI, datasets, active map layer, persisted QA/QC results and exports.
 - It suggests the next operator action based on missing V1 loop state without calling new APIs or adding backend behavior.
 - The status strip is implemented in `src/components/WorkbenchStatusStrip.tsx` and remains driven by `App.tsx` orchestration state.
+- MapLibre source/layer updates now wait for style readiness to avoid runtime blank-screen failures during first render.
 
 ## Release hardening updates
 

frontend/src/components/GeoMap.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useRef } from 'react'
+import { useEffect, useRef, useState } from 'react'
 import maplibregl from 'maplibre-gl'
 import 'maplibre-gl/dist/maplibre-gl.css'
 
@@ -63,6 +63,7 @@ function GeoMap({
   const containerRef = useRef<HTMLDivElement | null>(null)
   const mapRef = useRef<maplibregl.Map | null>(null)
   const onFeatureSelectRef = useRef<GeoMapProps['onFeatureSelect']>(onFeatureSelect)
+  const [mapStyleReady, setMapStyleReady] = useState(false)
 
   useEffect(() => {
     onFeatureSelectRef.current = onFeatureSelect
@@ -80,6 +81,9 @@ function GeoMap({
       zoom: 9,
     })
     map.addControl(new maplibregl.NavigationControl(), 'top-right')
+    map.on('load', () => {
+      setMapStyleReady(true)
+    })
     map.on('click', (event) => {
       const layers = ['dataset-fill', 'dataset-line', 'area-fill', 'area-line'].filter((layerId) => map.getLayer(layerId))
       if (layers.length === 0) {
@@ -101,12 +105,13 @@ function GeoMap({
     return () => {
       map.remove()
       mapRef.current = null
+      setMapStyleReady(false)
     }
   }, [])
 
   useEffect(() => {
     const map = mapRef.current
-    if (!map) {
+    if (!map || !mapStyleReady || !map.isStyleLoaded()) {
       return
     }
 
@@ -174,11 +179,11 @@ function GeoMap({
         }
       }
     }
-  }, [data])
+  }, [data, mapStyleReady])
 
   useEffect(() => {
     const map = mapRef.current
-    if (!map) {
+    if (!map || !mapStyleReady || !map.isStyleLoaded()) {
       return
     }
 
@@ -231,11 +236,11 @@ function GeoMap({
         map.fitBounds(bounds, { padding: 40 })
       }
     }
-  }, [areaData, data])
+  }, [areaData, data, mapStyleReady])
 
   useEffect(() => {
     const map = mapRef.current
-    if (!map) {
+    if (!map || !mapStyleReady || !map.isStyleLoaded()) {
       return
     }
     const visibility = visible ? 'visible' : 'none'
@@ -247,11 +252,11 @@ function GeoMap({
       map.setLayoutProperty('dataset-line', 'visibility', visibility)
       map.setPaintProperty('dataset-line', 'line-opacity', visible ? 1 : 0)
     }
-  }, [visible, opacity, data])
+  }, [visible, opacity, data, mapStyleReady])
 
   useEffect(() => {
     const map = mapRef.current
-    if (!map) {
+    if (!map || !mapStyleReady || !map.isStyleLoaded()) {
       return
     }
     const visibility = areaVisible ? 'visible' : 'none'
@@ -263,7 +268,7 @@ function GeoMap({
       map.setLayoutProperty('area-line', 'visibility', visibility)
       map.setPaintProperty('area-line', 'line-opacity', areaVisible ? 1 : 0)
     }
-  }, [areaVisible, areaOpacity, areaData])
+  }, [areaVisible, areaOpacity, areaData, mapStyleReady])
 
   return <div className="map-container" ref={containerRef} />
 }