fix(master): remember the tag's deployed digest after any tag job (#9)

Renames last_auto_digest to last_tag_digest. FinishJob sets it to the pinned
digest after any successful job whose to_ref had no digest, so a rollback
holds however the update was started.

internal/e2e/agent_master_test.go

@@ -91,14 +91,14 @@ func (m *memStore) SetPollError(_ context.Context, ids []int64, msg string) erro
 	return nil
 }
 
-func (m *memStore) SetLastAutoDigest(_ context.Context, id int64, digest string) error {
+func (m *memStore) SetLastTagDigest(_ context.Context, id int64, digest string) error {
 	m.mu.Lock()
 	defer m.mu.Unlock()
 	svc, ok := m.svcRows[id]
 	if !ok {
 		return model.ErrNotFound
 	}
-	svc.LastAutoDigest = digest
+	svc.LastTagDigest = digest
 	m.svcRows[id] = svc
 	return nil
 }
@@ -241,6 +241,9 @@ func (m *memStore) FinishJob(_ context.Context, agentID, jobID int64, f model.Jo
 	if f.Status == model.JobSucceeded {
 		svc := m.svcRows[j.ServiceID]
 		svc.DesiredRef = f.Ref
+		if _, d, _ := strings.Cut(f.Ref, "@"); !strings.Contains(requestedRef, "@") && d != "" {
+			svc.LastTagDigest = d
+		}
 		// Same rule as the SQL: the job was created for the suggested ref after it was reported.
 		requested, digest, _ := strings.Cut(requestedRef, "@")
 		if svc.AvailableAt != nil && svc.AvailableRef == requested && !svc.AvailableAt.After(j.CreatedAt) &&

internal/e2e/versions_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
+	"github.com/shcizo/package-updater/internal/master/jobs"
 	"github.com/shcizo/package-updater/internal/master/model"
 	"github.com/shcizo/package-updater/internal/master/poller"
 	"github.com/shcizo/package-updater/internal/protocol"
@@ -88,7 +89,7 @@ func TestPollStartsAutoJob(t *testing.T) {
 	assert.Equal(t, slusk+":1.4.2", svc.AvailableRef)
 	assert.Equal(t, "sha256:new", svc.AvailableDigest)
 	assert.Equal(t, model.SourcePoll, svc.AvailableSource)
-	assert.Equal(t, "sha256:new", svc.LastAutoDigest)
+	assert.Equal(t, "sha256:new", svc.LastTagDigest)
 
 	p.Cycle(context.Background())
 
@@ -97,3 +98,36 @@ func TestPollStartsAutoJob(t *testing.T) {
 	close(env.exec.release)
 	env.waitStatus(t, job.ID, model.JobSucceeded)
 }
+
+// An update started by the webhook, then a rollback by hand: polling must not
+// redo the update while the registry still shows the digest that was deployed.
+func TestPollKeepsARollbackAfterAWebhookUpdate(t *testing.T) {
+	env := newJobEnv(t)
+	ctx := context.Background()
+	close(env.exec.release)
+	env.store.seedService(model.Service{ID: 1, Kind: protocol.KindCompose, ComposeProject: "slusk", ComposeService: "web",
+		AgentID: ptr(agentID), ImageRepo: slusk, ActualRef: slusk + ":main@sha256:old", ActualDigest: "sha256:old",
+		UpdateMode: model.ModeAuto})
+	env.store.seedVersion(model.ImageVersion{ID: 5, Repo: slusk, Tag: "main", Digest: "sha256:old", Source: model.SourceRunning})
+	svc, err := env.store.GetService(ctx, 1)
+	require.NoError(t, err)
+
+	hook, err := env.jobs.Start(ctx, svc, jobs.StartRequest{Trigger: model.TriggerWebhook, Ref: slusk + ":main"})
+	require.NoError(t, err)
+	env.waitStatus(t, hook.ID, model.JobSucceeded)
+	svc, err = env.store.GetService(ctx, 1)
+	require.NoError(t, err)
+	assert.Equal(t, "sha256:e2e", svc.LastTagDigest, "the deployed digest of the tag is remembered")
+
+	pick, err := env.jobs.TriggerVersion(ctx, 1, 5, "alice")
+	require.NoError(t, err)
+	env.waitStatus(t, pick.ID, model.JobSucceeded)
+	jobsBefore := env.store.jobCount()
+
+	reg := &fixedRegistry{digests: map[string]string{slusk + ":main": "sha256:e2e"}}
+	p := poller.New(env.store, env.jobs, reg, env.m.broker, poller.Config{Workers: 1}, slog.New(slog.NewTextHandler(io.Discard, nil)))
+	p.Cycle(ctx)
+
+	assert.Equal(t, 1, reg.calls)
+	assert.Equal(t, jobsBefore, env.store.jobCount(), "the rollback stays")
+}