fix(admin): re-acquisition settings take effect without a restart, and say why a save was refused (#3936, #3937)

#3936: Router() built a reacquisition.SettingsService of its own, so a save
from the admin card refreshed that instance's cache while the sweeper in
main.go kept serving what it loaded at boot. The card showed the new
policy, the feature ran the old one, and only a restart reconciled them.
main.go now hands its instance to the server (srv.ReacqSettings), as it
already did for RecSettings, TagSettings and FingerprintSettings, and
Router() constructs one only when that field is nil. The regression test
saves through the router and reads the sweeper's instance.

#3937: the card's catch tested `e instanceof Error`, but api.put throws a
plain {code, message, status} object, so every reason the server gave was
discarded in favour of "Couldn't save settings." It now uses errMessage,
which appends the server's message for invalid_setting. Its test rejected
with an Error no code path produces, so it passed throughout; it now
rejects with what the client actually throws.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SQ31KQpYbStyK5y58UmPLH

internal/server/server.go

@@ -105,6 +105,11 @@ type Server struct {
 	// fingerprint workers, so a save from the admin card reaches them without a
 	// restart. Router() constructs a fallback when nil (tests).
 	FingerprintSettings *library.FingerprintSettingsService
+	// ReacqSettings is the DB-backed missing-file re-acquisition policy
+	// (milestone #290) — the same instance the sweeper in cmd/minstrel/main.go
+	// reads, so a save from the admin card reaches it without a restart
+	// (#3936). Router() constructs a fallback when nil (tests).
+	ReacqSettings *reacquisition.SettingsService
 	// StreamSecret is the HMAC key used by /api/cast/stream-token to
 	// mint signed UPnP / Sonos stream URLs and by /api/tracks/{id}/stream
 	// to verify them. Sourced from config.Config.StreamSecret. Tests that
@@ -157,13 +162,18 @@ func (s *Server) Router() http.Handler {
 			return lidarr.NewClient(cfg.BaseURL, cfg.APIKey)
 		}
 		lidarrReqs := lidarrrequests.NewService(s.Pool, lidarrCfg, lidarrClientFn, nil)
-		// Always usable even when the load fails — it falls back to the
-		// shipped defaults rather than leaving the admin card unable to
-		// render (same posture as netsettings above).
-		reacqSettings, raErr := reacquisition.NewSettingsService(
-			context.Background(), s.Pool, s.Logger)
-		if raErr != nil {
-			s.Logger.Warn("reacquisition settings unavailable; serving defaults", "err", raErr)
+		reacqSettings := s.ReacqSettings
+		if reacqSettings == nil {
+			// Test contexts construct Server without main.go's boot wiring.
+			// Always usable even when the load fails — it falls back to the
+			// shipped defaults rather than leaving the admin card unable to
+			// render (same posture as netsettings above).
+			var raErr error
+			reacqSettings, raErr = reacquisition.NewSettingsService(
+				context.Background(), s.Pool, s.Logger)
+			if raErr != nil {
+				s.Logger.Warn("reacquisition settings unavailable; serving defaults", "err", raErr)
+			}
 		}
 		lidarrQuar := lidarrquarantine.NewService(s.Pool, lidarrCfg, lidarrClientFn, s.DataDir)
 		tracksSvc := tracks.NewService(s.Pool, s.Logger, lidarrUnmonitorAdapter{fn: lidarrClientFn}, s.DataDir)

internal/server/server_test.go

@@ -1,6 +1,7 @@
 package server
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
 	"io"
@@ -20,6 +21,7 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/db"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/library"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/reacquisition"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/subsonic"
 )
 
@@ -242,6 +244,110 @@ func TestRouter_AdminSubtreeNotShadowed(t *testing.T) {
 	}
 }
 
+// TestRouter_ReacquisitionSettingsSavedThroughTheAPIReachTheSweeper is a
+// regression test for #3936. Router() used to construct a
+// reacquisition.SettingsService of its own, so a save from the admin card
+// refreshed THAT instance's cache while the sweeper in cmd/minstrel/main.go
+// kept serving what it had loaded at boot. The card showed the new policy, the
+// feature kept running the old one, and only a restart reconciled them — the
+// exact thing rule 25 says a setting must not need.
+//
+// The assertion is made against the instance main.go hands the sweeper: save
+// through the router, then read that instance. A second service leaves it stale.
+func TestRouter_ReacquisitionSettingsSavedThroughTheAPIReachTheSweeper(t *testing.T) {
+	dsn := os.Getenv("MINSTREL_TEST_DATABASE_URL")
+	if dsn == "" {
+		t.Skip("MINSTREL_TEST_DATABASE_URL not set")
+	}
+	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
+	if err := db.Migrate(dsn, logger); err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+	pool, err := pgxpool.New(context.Background(), dsn)
+	if err != nil {
+		t.Fatalf("pool: %v", err)
+	}
+	t.Cleanup(pool.Close)
+
+	ctx := context.Background()
+	q := dbq.New(pool)
+	_, _ = pool.Exec(ctx, "DELETE FROM sessions WHERE user_agent = 'reacq-settings-test'")
+	_, _ = pool.Exec(ctx, "DELETE FROM users WHERE username = 'test-reacq-settings-admin'")
+	user, err := q.CreateUser(ctx, dbq.CreateUserParams{
+		Username:     "test-reacq-settings-admin",
+		PasswordHash: "x",
+		ApiToken:     "test-reacq-settings-token",
+		IsAdmin:      true,
+	})
+	if err != nil {
+		t.Fatalf("CreateUser: %v", err)
+	}
+	t.Cleanup(func() { _, _ = pool.Exec(ctx, "DELETE FROM users WHERE id = $1", user.ID) })
+	token := "reacq-settings-test-" + time.Now().Format("20060102150405.000000")
+	tokenHash := auth.HashSessionToken(token)
+	if _, err := pool.Exec(ctx,
+		"INSERT INTO sessions (user_id, token_hash, user_agent) VALUES ($1, $2, 'reacq-settings-test')",
+		user.ID, tokenHash[:],
+	); err != nil {
+		t.Fatalf("insert session: %v", err)
+	}
+
+	// The sweeper's service. Nothing else in the process may write to the
+	// settings for the assertion below to mean what it says.
+	sweeperSettings, err := reacquisition.NewSettingsService(ctx, pool, logger)
+	if err != nil {
+		t.Fatalf("reacquisition settings: %v", err)
+	}
+	before := sweeperSettings.Get()
+	t.Cleanup(func() {
+		if _, err := sweeperSettings.Set(context.Background(), before); err != nil {
+			t.Errorf("restore reacquisition settings: %v", err)
+		}
+	})
+	wantGrace := before.GraceHours + 1
+	if wantGrace > 720 {
+		wantGrace = before.GraceHours - 1
+	}
+
+	s := New(logger, pool, stubScanner{}, subsonic.Config{}, config.EventsConfig{},
+		config.RecommendationConfig{}, "", config.BrandingConfig{}, nil, nil, nil, library.RunScanConfig{})
+	s.ReacqSettings = sweeperSettings
+	ts := httptest.NewServer(s.Router())
+	defer ts.Close()
+
+	body, err := json.Marshal(map[string]any{
+		"enabled":            before.Enabled,
+		"grace_hours":        wantGrace,
+		"backoff_base_hours": before.BackoffBaseHours,
+		"backoff_max_hours":  before.BackoffMaxHours,
+		"max_attempts":       before.MaxAttempts,
+		"max_per_pass":       before.MaxPerPass,
+		"auto_approve":       before.AutoApprove,
+	})
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	req, err := http.NewRequest(http.MethodPut, ts.URL+"/api/admin/library/reacquisition", bytes.NewReader(body))
+	if err != nil {
+		t.Fatalf("build request: %v", err)
+	}
+	req.Header.Set("Authorization", "Bearer "+token)
+	req.Header.Set("Content-Type", "application/json")
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		t.Fatalf("PUT reacquisition settings: %v", err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("PUT reacquisition settings: status = %d, want 200", resp.StatusCode)
+	}
+
+	if got := sweeperSettings.Get().GraceHours; got != wantGrace {
+		t.Fatalf("the sweeper's settings hold grace_hours = %d after the save, want %d — "+
+			"the API wrote through a different service instance", got, wantGrace)
+	}
+}
+
 // stubScanner is a no-op ScanTrigger used only to make Server.Router()
 // register /api/admin/scan. Its Scan method must never be called by the
 // route-presence assertions in this file.