Fix #144: Crash with Immersive Engineering fluid pipes (#147)

Author: Technici4n

src/main/java/dev/technici4n/moderndynamics/network/NodeHost.java

@@ -147,16 +147,33 @@ public final void refreshSelf() {
     @Nullable
     public abstract Object getApiInstance(BlockCapability<?, Direction> lookup, @Nullable Direction side);
 
+    /**
+     * Returns null if the node is not available.
+     * Throws an exception if the host is not on the logical server.
+     */
     @SuppressWarnings("unchecked")
+    // TODO: consider making this not nullable
     @Nullable
-    protected final <H extends NodeHost, C extends NetworkCache<H, C>> NetworkNode<H, C> findNode() {
-        // TODO: not the best unchecked cast...
+    protected final <H extends NodeHost, C extends NetworkCache<H, C>> NetworkNode<H, C> findNodeOnServer() {
         return getManager().findNode((ServerLevel) pipe.getLevel(), pipe.getBlockPos());
     }
 
+    /**
+     * Returns null on the client side or if the node is not available.
+     */
+    @SuppressWarnings("unchecked")
+    @Nullable
+    protected final <H extends NodeHost, C extends NetworkCache<H, C>> NetworkNode<H, C> findNode() {
+        if (pipe.getLevel() instanceof ServerLevel serverLevel) {
+            return getManager().findNode(serverLevel, pipe.getBlockPos());
+        } else {
+            return null;
+        }
+    }
+
     public final void separateNetwork() {
         @Nullable
-        NetworkNode<?, ?> node = findNode();
+        NetworkNode<?, ?> node = findNodeOnServer();
 
         if (node != null && node.getHost() == this) {
             node.getNetworkCache().separate();
@@ -181,7 +198,7 @@ public final void scheduleUpdate() {
         if (!needsUpdate) {
             needsUpdate = true;
             @Nullable
-            NetworkNode node = findNode();
+            NetworkNode node = findNodeOnServer();
 
             if (node != null) {
                 node.getNetworkCache().scheduleHostUpdate(this);

src/main/java/dev/technici4n/moderndynamics/network/item/ItemHost.java

@@ -113,7 +113,7 @@ private IItemHandler buildExternalNetworkInjectStorage(Direction side) {
                 double speedupFactor = getAttachment(side) instanceof ItemAttachedIo io ? io.getItemSpeedupFactor() : 1;
                 return cache.insertList(node, paths, resource, maxAmount, simulate, speedupFactor, null);
             } else {
-                // The node can be null if the pipe was just placed, and not initialized yet.
+                // The node can be null on the client or if the pipe was just placed and not initialized yet.
                 return 0;
             }
         });
@@ -125,7 +125,7 @@ private IItemHandler buildExternalNetworkInjectStorage(Direction side) {
     private InsertionOnlyItemHandler buildExtractorNetworkInjectStorage(Direction side, ItemAttachedIo extractor,
             @Nullable MaxParticipant maxIndexParticipant) {
         double speedupFactor = extractor.getItemSpeedupFactor();
-        NetworkNode<ItemHost, ItemCache> node = findNode();
+        NetworkNode<ItemHost, ItemCache> node = findNodeOnServer();
         var cache = node.getNetworkCache();
         var paths = rearrangePaths(cache.pathCache.getPaths(node, side.getOpposite()), extractor);
         return new InsertionOnlyItemHandler((resource, maxAmount, simulate) -> {
@@ -233,7 +233,7 @@ public void tickAttractor(Direction side, ItemAttachedIo attractor) {
             if (!insertTarget.hasStorage())
                 return;
 
-            NetworkNode<ItemHost, ItemCache> thisNode = findNode();
+            NetworkNode<ItemHost, ItemCache> thisNode = findNodeOnServer();
             var cache = thisNode.getNetworkCache();
             var pathCache = cache.pathCache;
             var paths = rearrangePaths(pathCache.getPaths(thisNode, side.getOpposite()), attractor);
@@ -356,7 +356,7 @@ public void tickMovingItems() {
 
                 @Nullable
                 ItemHost adjacentItemHost = null;
-                NetworkNode<ItemHost, ItemCache> ownNode = findNode();
+                NetworkNode<ItemHost, ItemCache> ownNode = findNodeOnServer();
                 for (var connection : ownNode.getConnections()) {
                     if (connection.direction() == adjPipeDirection) {
                         adjacentItemHost = connection.target().getHost();
@@ -486,7 +486,7 @@ public void gatherCapabilities() {
 
         if (oldConnections != inventoryConnections) {
             pipe.sync();
-            NetworkNode<ItemHost, ItemCache> node = findNode();
+            NetworkNode<ItemHost, ItemCache> node = findNodeOnServer();
             node.getNetworkCache().pathCache.invalidate();
         }
     }