fix: harden engine across casino, economy, concurrency, security, and content

1 files changed, 12 insertions, 3 deletions

diff --git a/internal/game/sys_triggers.go b/internal/game/sys_triggers.go
index 2dbde9f..312fe50 100644
--- a/internal/game/sys_triggers.go
+++ b/internal/game/sys_triggers.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"sort"
 	"strings"
 	"sync"
 
@@ -98,9 +99,17 @@ func (g *Game) startSequence(sess *net.Session, p *player.Player, steps []behavi
 // sequences are removed.
 func (g *Game) SequenceTick() {
 	g.seqMu.Lock()
-	playerSeqs := make([]*sequence, 0, len(g.sequences))
-	for _, s := range g.sequences {
-		playerSeqs = append(playerSeqs, s)
+	// g.sequences is a map: collect its keys and sort them so the per-tick
+	// order in which simultaneous sequences advance is reproducible (the
+	// determinism contract in building_guide/tick_order.md).
+	keys := make([]string, 0, len(g.sequences))
+	for key := range g.sequences {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+	playerSeqs := make([]*sequence, 0, len(keys))
+	for _, key := range keys {
+		playerSeqs = append(playerSeqs, g.sequences[key])
 	}
 	globalSeqs := append([]*sequence(nil), g.globalSeqs...)
 	g.seqMu.Unlock()