fix(matchdoor): skip DeclareBlockersReq when zero legal blockers

.gitignore

@@ -68,6 +68,7 @@ app/main/proto/messages.proto
 
 !.claude/
 .claude/CLAUDE.md
+.claude/worktrees/
 
 # Contains creds
 deploy/services-proxy.conf

matchdoor/src/main/kotlin/leyline/match/CombatHandler.kt

@@ -10,6 +10,7 @@ import leyline.bridge.SeatId
 import leyline.bridge.Target
 import leyline.game.BundleBuilder
 import leyline.game.GameBridge
+import leyline.game.RequestBuilder
 import org.slf4j.LoggerFactory
 import wotc.mtgo.gre.external.messaging.Messages.*
 import kotlin.collections.iterator
@@ -335,7 +336,17 @@ class CombatHandler(private val ops: SessionOps) {
                     // captured AI actions between the last drain and now.
                     drainPendingPlayback(bridge)
                     ops.traceEvent(MatchEventType.COMBAT_PROMPT, game, "DeclareBlockers attackers=${combat.attackers.size}")
-                    sendDeclareBlockersReq(bridge)
+                    val skipBlockers = sendDeclareBlockersReq(bridge)
+                    if (skipBlockers) {
+                        // Zero legal blockers — submit empty declaration and advance
+                        val seatBridge = bridge.seat(ops.seatId)
+                        val pending = seatBridge.action.getPending()
+                        if (pending != null) {
+                            seatBridge.action.submitAction(pending.actionId, PlayerAction.DeclareBlockers(emptyMap()))
+                            bridge.awaitPriority()
+                        }
+                        return Signal.SEND_STATE
+                    }
                     return Signal.STOP
                 } else if (isHumanTurn && combat != null && combat.attackers.isNotEmpty()) {
                     ops.traceEvent(MatchEventType.SEND_STATE, game, "AI blocking result")
@@ -421,13 +432,21 @@ class CombatHandler(private val ops: SessionOps) {
         ops.sendBundledGRE(result.messages)
     }
 
-    private fun sendDeclareBlockersReq(bridge: GameBridge) {
-        val game = bridge.getGame() ?: return
-        val result = BundleBuilder.declareBlockersBundle(game, bridge, ops.matchId, ops.seatId, ops.counter)
+    private fun sendDeclareBlockersReq(bridge: GameBridge): Boolean {
+        val game = bridge.getGame() ?: return false
+        val req = RequestBuilder.buildDeclareBlockersReq(game, ops.seatId, bridge)
 
+        if (req.blockersCount == 0) {
+            log.info("CombatHandler: zero legal blockers — auto-submitting empty declaration")
+            pendingBlockersSent = true
+            return true // caller should auto-advance
+        }
+
+        val result = BundleBuilder.declareBlockersBundle(game, bridge, ops.matchId, ops.seatId, ops.counter)
         pendingBlockersSent = true
         Tap.outboundTemplate("DeclareBlockersReq seat=${ops.seatId}")
         ops.sendBundledGRE(result.messages)
+        return false
     }
 
     /**

matchdoor/src/test/kotlin/leyline/conformance/ZeroBlockersTest.kt

@@ -0,0 +1,72 @@
+package leyline.conformance
+
+import io.kotest.core.spec.style.FunSpec
+import io.kotest.matchers.booleans.shouldBeFalse
+import leyline.IntegrationTag
+
+/**
+ * Regression: when the defending player has zero legal blockers, the server
+ * should auto-advance through declare blockers instead of sending
+ * DeclareBlockersReq to the client (#188).
+ */
+class ZeroBlockersTest :
+    FunSpec({
+
+        tags(IntegrationTag)
+
+        var harness: MatchFlowHarness? = null
+
+        afterEach {
+            harness?.shutdown()
+            harness = null
+        }
+
+        test("zero blockers auto-advances without DeclareBlockersReq") {
+            // Human has only lands, AI has haste attackers
+            val pzl = """
+                [metadata]
+                Name:Zero Blockers AI Attack
+                Goal:Win
+                Turns:10
+                Difficulty:Easy
+                Description:Human has no creatures. AI attacks — should skip blockers.
+
+                [state]
+                ActivePlayer=Human
+                ActivePhase=Main1
+                HumanLife=20
+                AILife=20
+
+                humanbattlefield=Plains;Plains
+                humanlibrary=Plains;Plains;Plains;Plains;Plains
+                aibattlefield=Mountain;Mountain;Raging Goblin;Raging Goblin
+                ailibrary=Mountain;Mountain;Mountain;Mountain;Mountain
+            """.trimIndent()
+
+            val h = MatchFlowHarness(seed = 42L, validating = false)
+            harness = h
+            h.connectAndKeepPuzzleText(
+                pzl,
+                aiScript = listOf(
+                    ScriptedAction.Attack(listOf("Raging Goblin")),
+                    ScriptedAction.PassPriority,
+                ),
+            )
+
+            val snap = h.messageSnapshot()
+
+            // Pass through human turn into AI combat
+            h.passPriority()
+
+            // Pass through combat — should auto-advance without blockers prompt
+            h.passThroughCombat()
+
+            // No DeclareBlockersReq should have been sent
+            val msgs = h.messagesSince(snap)
+            val blockerReq = msgs.any { it.hasDeclareBlockersReq() }
+            blockerReq.shouldBeFalse()
+
+            // Game should still be running (not stuck)
+            h.isGameOver().shouldBeFalse()
+        }
+    })