From bdb5845cecc777ded4e37071a9ae976a8dcbe0d1 Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <dktapps@pmmp.io>
Date: Mon, 5 Aug 2024 22:33:30 +0100
Subject: [PATCH] Allow name flattening rules where multiple old values map to
 the same new ID this allows more compaction in certain cases, such as
 tallgrass recently. instead of blacklisting any mapping which reuses the same
 flattened infix, we select the flatten property which produces the smallest
 number of distinct rules, which produces the most compact schema possible.
 this change also permits potentially flattening other types of properties
 such as for corals (live/dead and type), although only one may be selected at
 a time.

---
 tools/generate-blockstate-upgrade-schema.php | 30 +++++++++++++-------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/tools/generate-blockstate-upgrade-schema.php b/tools/generate-blockstate-upgrade-schema.php
index 54984d459..299d97d05 100644
--- a/tools/generate-blockstate-upgrade-schema.php
+++ b/tools/generate-blockstate-upgrade-schema.php
@@ -42,6 +42,7 @@ use function array_key_last;
 use function array_keys;
 use function array_map;
 use function array_shift;
+use function array_unique;
 use function array_values;
 use function count;
 use function dirname;
@@ -423,6 +424,10 @@ function processRemappedStates(array $upgradeTable) : array{
 
 			$filter = $pair->old->getStates();
 			foreach($unchangedStatesByNewName[$pair->new->getName()] as $unchangedPropertyName){
+				if($unchangedPropertyName === $propertyName){
+					$notFlattenedProperties[$propertyName] = true;
+					continue 2;
+				}
 				unset($filter[$unchangedPropertyName]);
 			}
 			unset($filter[$propertyName]);
@@ -436,26 +441,31 @@ function processRemappedStates(array $upgradeTable) : array{
 					$notFlattenedProperties[$propertyName] = true;
 					continue;
 				}
-				foreach(Utils::stringifyKeys($valuesToIds) as $otherRawValue => $otherNewId){
-					if($otherRawValue === $rawValue){
-						continue;
-					}
-					if($otherNewId === $pair->new->getName()){
-						//this old value maps to the same new ID as another old value - bad candidate for flattening
-						$notFlattenedProperties[$propertyName] = true;
-						continue 2;
-					}
-				}
 			}
 			$candidateFlattenedValues[$propertyName][$rawFilter][$rawValue] = $pair->new->getName();
 		}
 	}
+	foreach(Utils::stringifyKeys($candidateFlattenedValues) as $propertyName => $filters){
+		foreach($filters as $valuesToIds){
+			if(count(array_unique($valuesToIds)) === 1){
+				//this property doesn't influence the new ID
+				$notFlattenedProperties[$propertyName] = true;
+				continue 2;
+			}
+		}
+	}
 	foreach(Utils::stringifyKeys($notFlattenedProperties) as $propertyName => $_){
 		unset($candidateFlattenedValues[$propertyName]);
 	}
 
 	$flattenedProperties = buildFlattenPropertyRules($candidateFlattenedValues);
 	$flattenProperty = array_key_first($flattenedProperties);
+	//Properties with fewer rules take up less space for the same result
+	foreach(Utils::stringifyKeys($flattenedProperties) as $propertyName => $rules){
+		if(count($rules) < count($flattenedProperties[$flattenProperty])){
+			$flattenProperty = $propertyName;
+		}
+	}
 
 	$list = [];