Make snapshot projections self-diagnosing

internal/agent/runner/runner.go

@@ -77,6 +77,12 @@ func (r *Runner) resticEnv() restic.Env {
 	}
 }
 
+// RefreshSnapshots reconciles the server's cached projection without running
+// a mutating repository job.
+func (r *Runner) RefreshSnapshots(ctx context.Context) error {
+	return r.reportSnapshots(ctx, r.resticEnv())
+}
+
 // sendStarted ships a job.started envelope.
 func (r *Runner) sendStarted(jobID string, kind api.JobKind, startedAt time.Time) {
 	env, _ := api.Marshal(api.MsgJobStarted, jobID, api.JobStartedPayload{
@@ -226,14 +232,9 @@ func (r *Runner) RunBackup(ctx context.Context, jobID string, paths, excludes, t
 		}
 	}
 
-	r.sendFinished(ctx, jobID, finishedAt, err, statsBlob)
-
 	// On a successful backup, refresh the server's snapshot projection.
-	// We do this *after* job.finished so the UI sees the job land first;
-	// the snapshot list is a follow-up that the host detail page polls
-	// or the dashboard sees on its next refresh. A failure here is
-	// logged but doesn't fail the job — the next successful backup will
-	// catch the projection up.
+	// Do this before job.finished so a failure in terminal reporting cannot
+	// prevent the independently useful projection refresh.
 	if err == nil {
 		if rerr := r.reportSnapshots(ctx, env); rerr != nil {
 			slog.Warn("runner: snapshots.report failed", "job_id", jobID, "err", rerr)
@@ -242,6 +243,7 @@ func (r *Runner) RunBackup(ctx context.Context, jobID string, paths, excludes, t
 			slog.Warn("runner: stats.report after backup failed", "job_id", jobID, "err", rerr)
 		}
 	}
+	r.sendFinished(ctx, jobID, finishedAt, err, statsBlob)
 
 	if err != nil {
 		return fmt.Errorf("runner backup: %w", err)
@@ -282,8 +284,6 @@ func (r *Runner) RunForget(ctx context.Context, jobID string, groups []restic.Fo
 	var seq atomic.Int64
 	err := env.RunForget(ctx, groups, dryRun, r.streamHandler(jobID, &seq))
 	finishedAt := time.Now().UTC()
-	r.sendFinished(ctx, jobID, finishedAt, err, nil)
-
 	// Refresh the server's snapshot projection — forget rewrites the
 	// index so the host's snapshot list almost certainly shrunk.
 	if err == nil {
@@ -292,6 +292,7 @@ func (r *Runner) RunForget(ctx context.Context, jobID string, groups []restic.Fo
 				"job_id", jobID, "err", rerr)
 		}
 	}
+	r.sendFinished(ctx, jobID, finishedAt, err, nil)
 
 	if err != nil {
 		return fmt.Errorf("runner forget: %w", err)
@@ -318,6 +319,9 @@ func (r *Runner) RunPrune(ctx context.Context, jobID string) error {
 		if rerr := r.reportStats(ctx, env, api.RepoStatsPayload{LastPruneAt: &pruneAt}); rerr != nil {
 			slog.Warn("runner: stats.report after prune failed", "job_id", jobID, "err", rerr)
 		}
+		if rerr := r.reportSnapshots(ctx, env); rerr != nil {
+			slog.Warn("runner: snapshots.report after prune failed", "job_id", jobID, "err", rerr)
+		}
 	}
 
 	r.sendFinished(ctx, jobID, finishedAt, err, nil)