From 762c48e96b2956b075d93e0ab89cda3f7d701017 Mon Sep 17 00:00:00 2001
From: Stanislav Rossovskii <stas.rossovskii@gmail.com>
Date: Tue, 23 Jun 2026 20:04:08 +0400
Subject: [PATCH] Fix scheduler cleanup edge cases

---
 agent/internal/config/config.go            |  2 +-
 agent/internal/config/config_test.go       | 23 +++++++++++++++
 agent/internal/scheduler/scheduler.go      | 25 ++++++++--------
 agent/internal/scheduler/scheduler_test.go | 33 ++++++++++++++++++++++
 web/src/app/globals.css                    |  6 ----
 5 files changed, 69 insertions(+), 20 deletions(-)

diff --git a/agent/internal/config/config.go b/agent/internal/config/config.go
index 722b57c..7a78665 100644
--- a/agent/internal/config/config.go
+++ b/agent/internal/config/config.go
@@ -217,7 +217,7 @@ func (c *Config) Validate() error {
 			return fmt.Errorf("check %q: timeout must be > 0", ch.ID)
 		}
 		if ch.Interval.Duration < 0 {
-			return fmt.Errorf("check %q: interval must be > 0", ch.ID)
+			return fmt.Errorf("check %q: interval must not be negative", ch.ID)
 		}
 		ch.Cron = strings.TrimSpace(ch.Cron)
 		hasInterval := ch.Interval.Duration > 0
diff --git a/agent/internal/config/config_test.go b/agent/internal/config/config_test.go
index 3535a73..702a23e 100644
--- a/agent/internal/config/config_test.go
+++ b/agent/internal/config/config_test.go
@@ -123,6 +123,29 @@ func TestValidateCheckScheduleChoice(t *testing.T) {
 	}
 }
 
+func TestValidateNegativeIntervalMessage(t *testing.T) {
+	_, err := Load(writeTmp(t, `
+agent_id = "host-1"
+state_dir = "/tmp/x"
+
+[server]
+enabled = true
+url = "http://localhost"
+
+[[checks]]
+id = "c1"
+command = "true"
+interval = "-1s"
+timeout = "5s"
+`))
+	if err == nil {
+		t.Fatal("expected negative interval error")
+	}
+	if !strings.Contains(err.Error(), "interval must not be negative") {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
 func TestLoadResourceLimits(t *testing.T) {
 	c, err := Load(writeTmp(t, `
 	agent_id = "host-1"
diff --git a/agent/internal/scheduler/scheduler.go b/agent/internal/scheduler/scheduler.go
index 76fbb7e..9e96ffe 100644
--- a/agent/internal/scheduler/scheduler.go
+++ b/agent/internal/scheduler/scheduler.go
@@ -202,13 +202,24 @@ func (w *checkWorker) Wait() {
 }
 
 func (w *checkWorker) loop(initial config.CheckConfig) {
+	cfg := initial
+	stoppedNotified := false
+	notifyStopped := func() {
+		if stoppedNotified {
+			return
+		}
+		stoppedNotified = true
+		if w.hooks.OnStopped != nil {
+			w.hooks.OnStopped(cfg.ID)
+		}
+	}
 	defer func() {
+		notifyStopped()
 		if w.onDone != nil {
 			w.onDone(w)
 		}
 		w.wg.Done()
 	}()
-	cfg := initial
 	t := time.NewTimer(time.Hour)
 	stopTimer(t)
 	defer t.Stop()
@@ -249,9 +260,6 @@ func (w *checkWorker) loop(initial config.CheckConfig) {
 	}
 
 	if !arm(cfg, true) {
-		if w.hooks.OnStopped != nil {
-			w.hooks.OnStopped(cfg.ID)
-		}
 		return
 	}
 
@@ -261,18 +269,12 @@ func (w *checkWorker) loop(initial config.CheckConfig) {
 			stopping = true
 			ctxDone = nil
 			if !running {
-				if w.hooks.OnStopped != nil {
-					w.hooks.OnStopped(cfg.ID)
-				}
 				return
 			}
 		case <-stopCh:
 			stopping = true
 			stopCh = nil
 			if !running {
-				if w.hooks.OnStopped != nil {
-					w.hooks.OnStopped(cfg.ID)
-				}
 				return
 			}
 		case next := <-w.updateCh:
@@ -307,9 +309,6 @@ func (w *checkWorker) loop(initial config.CheckConfig) {
 				}
 			}
 			if stopping {
-				if w.hooks.OnStopped != nil {
-					w.hooks.OnStopped(cfg.ID)
-				}
 				return
 			}
 			if runAfterCurrent {
diff --git a/agent/internal/scheduler/scheduler_test.go b/agent/internal/scheduler/scheduler_test.go
index f9658ad..019fcd6 100644
--- a/agent/internal/scheduler/scheduler_test.go
+++ b/agent/internal/scheduler/scheduler_test.go
@@ -2,6 +2,7 @@ package scheduler
 
 import (
 	"context"
+	"errors"
 	"strings"
 	"sync/atomic"
 	"testing"
@@ -107,6 +108,38 @@ func TestCronEmitsOnDueSlot(t *testing.T) {
 	m.Wait()
 }
 
+func TestCronArmErrorCallsStoppedHook(t *testing.T) {
+	old := parseCronSchedule
+	var calls int32
+	parseCronSchedule = func(string) (cron.Schedule, error) {
+		if atomic.AddInt32(&calls, 1) == 1 {
+			return fakeCronSchedule{delay: 10 * time.Millisecond}, nil
+		}
+		return nil, errors.New("boom")
+	}
+	t.Cleanup(func() { parseCronSchedule = old })
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+	out := make(chan Event, 10)
+	stopped := make(chan string, 1)
+	m := NewManager(ctx, "a1", out, Hooks{
+		OnStopped: func(id string) { stopped <- id },
+	})
+	m.Update([]config.CheckConfig{mkCronCheck("cron", "true", 100*time.Millisecond)})
+
+	select {
+	case id := <-stopped:
+		if id != "cron" {
+			t.Fatalf("unexpected stopped id: %q", id)
+		}
+	case <-ctx.Done():
+		t.Fatal("stopped hook was not called")
+	}
+	m.Stop()
+	m.Wait()
+}
+
 func TestNoOverlapSkips(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 600*time.Millisecond)
 	defer cancel()
diff --git a/web/src/app/globals.css b/web/src/app/globals.css
index 3d44047..421b578 100644
--- a/web/src/app/globals.css
+++ b/web/src/app/globals.css
@@ -13,12 +13,6 @@
   --font-mono: var(--font-geist-mono);
 }
 
-:root[data-theme="dark"] {
-  --background: #0a0a0a;
-  --foreground: #ededed;
-  color-scheme: dark;
-}
-
 body {
   background: var(--background);
   color: var(--foreground);