Preserve W3I player count in synthesized headers

Author: Frotty

de.peeeq.wurstscript/src/main/java/de/peeeq/wurstio/languageserver/ProjectConfigBuilder.java

@@ -107,7 +107,7 @@ public static MapRequest.CompilationResult apply(WurstProjectConfigData projectC
         w3I.write(result.w3i);
 
         // Apply map header (this is cheap, so we always do it)
-        applyMapHeader(projectConfig, targetMap);
+        applyMapHeader(projectConfig, targetMap, w3I.getPlayers().size());
 
         // Update the manifest with new config hash (must open writable to insert)
         try (MpqEditor mpq = MpqEditorFactory.getEditor(Optional.of(targetMap), false)) {
@@ -356,7 +356,8 @@ private static void setVolatilePlayerConfig(WurstProjectBuildPlayer wplayer, W3I
         }
     }
 
-    private static void applyMapHeader(WurstProjectConfigData projectConfig, File targetMap) throws IOException {
+    private static void applyMapHeader(WurstProjectConfigData projectConfig, File targetMap,
+                                       int existingPlayerCount) throws IOException {
         boolean shouldWrite = false;
         WurstProjectBuildMapData buildMapData = projectConfig.buildMapData();
         if (buildMapData.players().isEmpty() && StringUtils.isBlank(buildMapData.name())) {
@@ -367,12 +368,15 @@ private static void applyMapHeader(WurstProjectConfigData projectConfig, File ta
         // directly with its MPQ archive. MapHeader.ofFile only reads the prefix,
         // so use a new header in that case; writeToMapFile will insert it before
         // the archive.
-        MapHeader mapHeader = startsWithMpqArchive(targetMap)
+        boolean hasNoMapHeader = startsWithMpqArchive(targetMap);
+        MapHeader mapHeader = hasNoMapHeader
             ? new MapHeader()
             : MapHeader.ofFile(targetMap);
         if (!buildMapData.players().isEmpty()) {
             mapHeader.setMaxPlayersCount(buildMapData.players().size());
             shouldWrite = true;
+        } else if (hasNoMapHeader) {
+            mapHeader.setMaxPlayersCount(existingPlayerCount);
         }
         if (StringUtils.isNotBlank(buildMapData.name())) {
             mapHeader.setMapName(buildMapData.name());

de.peeeq.wurstscript/src/test/java/tests/wurstscript/tests/WurstBuildConfigTests.java

@@ -236,7 +236,7 @@ public void mapHeaderConfigAcceptsAnArchiveWithoutAnHm3wPrefix() throws Exceptio
         Files.write(mapWithoutHeader, original);
 
         Method applyMapHeader = ProjectConfigBuilder.class.getDeclaredMethod(
-            "applyMapHeader", WurstProjectConfigData.class, File.class
+            "applyMapHeader", WurstProjectConfigData.class, File.class, int.class
         );
         applyMapHeader.setAccessible(true);
 
@@ -249,11 +249,12 @@ public void mapHeaderConfigAcceptsAnArchiveWithoutAnHm3wPrefix() throws Exceptio
                 null,
                 null
             ),
-            mapWithoutHeader.toFile()
+            mapWithoutHeader.toFile(),
+            3
         );
 
         assertEquals(Files.readAllBytes(mapWithoutHeader)[0], (byte) 'H');
-        assertEquals(MapHeader.ofFile(mapWithoutHeader.toFile()).getMaxPlayersCount(), 0);
+        assertEquals(MapHeader.ofFile(mapWithoutHeader.toFile()).getMaxPlayersCount(), 3);
         assertEquals(Files.size(mapWithoutHeader), original.length + 512);
     }
 
@@ -268,10 +269,10 @@ public void mapHeaderConfigDoesNotReadAnArchiveWhenNothingNeedsChanging() throws
         Files.write(mapWithoutHeader, original);
 
         Method applyMapHeader = ProjectConfigBuilder.class.getDeclaredMethod(
-            "applyMapHeader", WurstProjectConfigData.class, File.class
+            "applyMapHeader", WurstProjectConfigData.class, File.class, int.class
         );
         applyMapHeader.setAccessible(true);
-        applyMapHeader.invoke(null, WurstProjectConfigData.empty(), mapWithoutHeader.toFile());
+        applyMapHeader.invoke(null, WurstProjectConfigData.empty(), mapWithoutHeader.toFile(), 0);
 
         assertEquals(Files.readAllBytes(mapWithoutHeader), original);
     }