From 8eb9e23aa7ed0269cfc1cbbb8a9bfa9107bf3a25 Mon Sep 17 00:00:00 2001
From: Tor Andersson <tor@ccxvii.net>
Date: Fri, 16 Sep 2022 17:16:36 +0200
Subject: Oops! Supply lines do not radiate from water ways.

---
 rules.js | 50 +++++++++++++++++++++++++++++---------------------
 1 file changed, 29 insertions(+), 21 deletions(-)

diff --git a/rules.js b/rules.js
index 87b4763..13aae8b 100644
--- a/rules.js
+++ b/rules.js
@@ -2035,32 +2035,45 @@ function update_vp(name, s) {
 
 // SUPPLY LINES
 
+function is_cultivated_or_fortification_or_amphib(space) {
+	return is_cultivated(space) || has_friendly_fortifications(space) || has_friendly_amphib(space)
+}
+
 function search_supply_spaces_imp(queue) {
+	let visited = new Array(spaces.length).fill(0)
 	// console.log("======")
 	let reached = []
-	for (let s of queue)
+	for (let s of queue) {
 		set_add(reached, s)
+		visited[s] = 1
+	}
 	while (queue.length > 0) {
-		let current = queue.shift()
-		// If we must have come here by water way:
-		let cultivated = is_cultivated(current) || has_friendly_fortifications(current) || has_friendly_amphib(current)
-		// console.log("SUPPLY", space_name(current), cultivated)
-		for_each_exit_with_type(current, (next, type) => {
-			if (set_has(reached, next))
-				return // continue
+		let here = queue.shift()
+		// console.log("SUPPLY", space_name(here))
+		for_each_exit_with_type(here, (next, type) => {
+			if (visited[next])
+				return
 			if (has_unbesieged_enemy_units(next) || has_unbesieged_enemy_fortifications(next))
 				return // continue
-			if (!cultivated) {
-				// came from wilderness by water, must continue by water
-				if (type !== 'land') {
-					// console.log("    ", space_name(next), "(adjacent-water)")
+			if (is_cultivated_or_fortification_or_amphib(here)) {
+				// came from cultivated/fortification,
+				// may continue by water or another fortification
+				// may stop at anything
+				if (type !== 'land' || is_cultivated_or_fortification_or_amphib(next)) {
+					// console.log("    ", space_name(next), "(from cultivated, continue)")
 					set_add(reached, next)
+					visited[next] = 1
 					queue.push(next)
+				} else {
+					// console.log("    ", space_name(next), "(from cultivated, stop)")
+					// allow re-visits in case we come by water a longer way
+					set_add(reached, next)
 				}
 			} else {
-				// came from cultivated by any path, may continue to cultivated or by water
-				if (is_cultivated(next) || has_friendly_fortifications(next) || has_friendly_amphib(next) || type !== 'land') {
-					// console.log("    ", space_name(next), "(from land)")
+				// in wilderness, arrived by water, must continue by water
+				if (type !== 'land') {
+					// console.log("    ", space_name(next), "(from river)")
+					visited[next] = 1
 					set_add(reached, next)
 					queue.push(next)
 				}
@@ -2091,12 +2104,7 @@ function is_in_supply(from) {
 		search_supply_spaces()
 	if (set_has(supply_cache, from))
 		return true
-	let x = false
-	for_each_exit(from, next => {
-		if (set_has(supply_cache, next))
-			x = true
-	})
-	return x
+	return false
 }
 
 function query_supply() {
-- 
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