From fd09ca103fd9fd14f5d0ecd3df6efd839a9df560 Mon Sep 17 00:00:00 2001
From: Deluan <deluan@navidrome.org>
Date: Mon, 9 Feb 2026 16:42:05 -0500
Subject: [PATCH] fix(scanner): resolve data race on conf.Server access in
 getScanner

Captured DevExternalScanner config value in the controller struct at
construction time instead of reading the global conf.Server pointer in
getScanner(). The background goroutine spawned by ScanFolders() was
reading conf.Server.DevExternalScanner concurrently with test cleanup
reassigning the conf.Server pointer, causing a data race detected by
the race detector in the E2E test suite.
---
 scanner/controller.go | 38 ++++++++++++++++++++------------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/scanner/controller.go b/scanner/controller.go
index 635011840..db6444fa9 100644
--- a/scanner/controller.go
+++ b/scanner/controller.go
@@ -29,21 +29,22 @@ var (
 func New(rootCtx context.Context, ds model.DataStore, cw artwork.CacheWarmer, broker events.Broker,
 	pls core.Playlists, m metrics.Metrics) model.Scanner {
 	c := &controller{
-		rootCtx: rootCtx,
-		ds:      ds,
-		cw:      cw,
-		broker:  broker,
-		pls:     pls,
-		metrics: m,
+		rootCtx:            rootCtx,
+		ds:                 ds,
+		cw:                 cw,
+		broker:             broker,
+		pls:                pls,
+		metrics:            m,
+		devExternalScanner: conf.Server.DevExternalScanner,
 	}
-	if !conf.Server.DevExternalScanner {
+	if !c.devExternalScanner {
 		c.limiter = P(rate.Sometimes{Interval: conf.Server.DevActivityPanelUpdateRate})
 	}
 	return c
 }
 
 func (s *controller) getScanner() scanner {
-	if conf.Server.DevExternalScanner {
+	if s.devExternalScanner {
 		return &scannerExternal{}
 	}
 	return &scannerImpl{ds: s.ds, cw: s.cw, pls: s.pls}
@@ -92,16 +93,17 @@ type scanner interface {
 }
 
 type controller struct {
-	rootCtx         context.Context
-	ds              model.DataStore
-	cw              artwork.CacheWarmer
-	broker          events.Broker
-	metrics         metrics.Metrics
-	pls             core.Playlists
-	limiter         *rate.Sometimes
-	count           atomic.Uint32
-	folderCount     atomic.Uint32
-	changesDetected bool
+	rootCtx            context.Context
+	ds                 model.DataStore
+	cw                 artwork.CacheWarmer
+	broker             events.Broker
+	metrics            metrics.Metrics
+	pls                core.Playlists
+	limiter            *rate.Sometimes
+	devExternalScanner bool
+	count              atomic.Uint32
+	folderCount        atomic.Uint32
+	changesDetected    bool
 }
 
 // getLastScanTime returns the most recent scan time across all libraries