fix(actions): default-branch push discards a due schedule occurrence (#40073)

Default-branch pushes and Actions unit saves recreated the repository's
schedules with `Next` recomputed from that moment, so a push between a
cron's due minute and the scheduler's pass skipped the occurrence, and
`@every` timers restarted.

Re-registration now updates schedule rows in place and keeps the spec
rows of unchanged crons, so their cursor survives and an in-flight
scheduler pass still finds its schedule. Re-detection also clears
schedules when no scheduled workflow remains.

Fixes https://github.com/go-gitea/gitea/issues/40062

Written with AI assistance.

---------

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Claude (Opus 5.5) <noreply@anthropic.com>

models/actions/schedule.go

@@ -41,26 +41,57 @@ func init() {
 	db.RegisterModel(new(ActionSchedule))
 }
 
-// CreateScheduleTaskBySchedules creates new schedule task.
-func CreateScheduleTaskBySchedules(ctx context.Context, rows []*ActionSchedule) error {
-	// Return early if there are no rows to insert
-	if len(rows) == 0 {
-		return nil
-	}
+type scheduleSpecKey struct {
+	scheduleID int64
+	spec       string
+}
 
+// ReplaceScheduleTasksByRepo updates schedules in place and keeps the specs of unchanged crons, so re-registering cannot skip a due occurrence.
+func ReplaceScheduleTasksByRepo(ctx context.Context, repoID int64, rows []*ActionSchedule) error {
 	return db.WithTx(ctx, func(ctx context.Context) error {
+		var oldSchedules []*ActionSchedule
+		if err := db.GetEngine(ctx).Cols("id", "workflow_id").Where("repo_id = ?", repoID).Find(&oldSchedules); err != nil {
+			return err
+		}
+		var oldSpecs []*ActionScheduleSpec
+		if err := db.GetEngine(ctx).Cols("id", "schedule_id", "spec").Where("repo_id = ?", repoID).Find(&oldSpecs); err != nil {
+			return err
+		}
+		scheduleIDs := make(map[string]int64, len(oldSchedules))
+		for _, schedule := range oldSchedules {
+			scheduleIDs[schedule.WorkflowID] = schedule.ID
+		}
+		specIDs := make(map[scheduleSpecKey]int64, len(oldSpecs))
+		for _, spec := range oldSpecs {
+			specIDs[scheduleSpecKey{spec.ScheduleID, spec.Spec}] = spec.ID
+		}
+
+		var keptScheduleIDs, keptSpecIDs []int64
+
 		// Loop through each schedule row
 		for _, row := range rows {
 			row.Title = util.EllipsisDisplayString(row.Title, 255)
-			// Create new schedule row
-			if err := db.Insert(ctx, row); err != nil {
+			if id, ok := scheduleIDs[row.WorkflowID]; ok {
+				row.ID = id
+				if _, err := db.GetEngine(ctx).ID(id).AllCols().Update(row); err != nil {
+					return err
+				}
+			} else if err := db.Insert(ctx, row); err != nil {
 				return err
 			}
+			keptScheduleIDs = append(keptScheduleIDs, row.ID)
 
 			// Loop through each schedule spec and create a new spec row
 			now := time.Now()
 
 			for _, spec := range row.Specs {
+				key := scheduleSpecKey{row.ID, spec}
+				if id, ok := specIDs[key]; ok {
+					delete(specIDs, key)
+					keptSpecIDs = append(keptSpecIDs, id)
+					continue
+				}
+
 				specRow := &ActionScheduleSpec{
 					RepoID:     row.RepoID,
 					ScheduleID: row.ID,
@@ -81,9 +112,16 @@ func CreateScheduleTaskBySchedules(ctx context.Context, rows []*ActionSchedule)
 				if err = db.Insert(ctx, specRow); err != nil {
 					return err
 				}
+				keptSpecIDs = append(keptSpecIDs, specRow.ID)
 			}
 		}
-		return nil
+
+		// an empty NotIn matches every row
+		if _, err := db.GetEngine(ctx).Where("repo_id = ?", repoID).NotIn("id", keptScheduleIDs).Delete(&ActionSchedule{}); err != nil {
+			return err
+		}
+		_, err := db.GetEngine(ctx).Where("repo_id = ?", repoID).NotIn("id", keptSpecIDs).Delete(&ActionScheduleSpec{})
+		return err
 	})
 }
 

models/actions/schedule_test.go

@@ -0,0 +1,43 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package actions
+
+import (
+	"testing"
+	"time"
+
+	"gitea.dev/models/unittest"
+	"gitea.dev/modules/timeutil"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestReplaceScheduleTasksByRepo(t *testing.T) {
+	require.NoError(t, unittest.PrepareTestDatabase())
+
+	const repoID = 4711
+	register := func(commitSHA, spec string) {
+		require.NoError(t, ReplaceScheduleTasksByRepo(t.Context(), repoID, []*ActionSchedule{
+			{RepoID: repoID, WorkflowID: "nightly.yml", CommitSHA: commitSHA, Specs: []string{spec}},
+		}))
+	}
+
+	register("c1", "17 */6 * * *")
+	spec := unittest.AssertExistsAndLoadBean(t, &ActionScheduleSpec{RepoID: repoID})
+	spec.Next = timeutil.TimeStamp(time.Now().Add(-time.Minute).Unix())
+	require.NoError(t, UpdateScheduleSpec(t.Context(), spec, "next"))
+
+	register("c2", "17 */6 * * *")
+	unittest.AssertExistsAndLoadBean(t, &ActionSchedule{ID: spec.ScheduleID, CommitSHA: "c2"})
+	unittest.AssertExistsAndLoadBean(t, &ActionScheduleSpec{ID: spec.ID, ScheduleID: spec.ScheduleID, Next: spec.Next})
+
+	register("c3", "23 */6 * * *")
+	unittest.AssertNotExistsBean(t, &ActionScheduleSpec{ID: spec.ID})
+	assert.Greater(t, unittest.AssertExistsAndLoadBean(t, &ActionScheduleSpec{RepoID: repoID}).Next, spec.Next)
+
+	require.NoError(t, ReplaceScheduleTasksByRepo(t.Context(), repoID, nil))
+	unittest.AssertNotExistsBean(t, &ActionSchedule{RepoID: repoID})
+	unittest.AssertNotExistsBean(t, &ActionScheduleSpec{RepoID: repoID})
+}