From: Matt Corallo <git@bluematt.me>
Date: Thu, 11 Nov 2021 17:34:41 +0000 (+0000)
Subject: Hold a reference when we pass Option<Trait> to rust
X-Git-Tag: v0.0.103.1^2~16
X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=commitdiff_plain;h=a46cc8c472582d1b094f73ded7d691c4695bed0d;p=ldk-java

Hold a reference when we pass Option<Trait> to rust

This resolves a NPE when calling trait methods if the user doesn't
hold their own reference to the underlying trait, which is quite
possible for, eg, the `Filter` object.

We also adapt `HumanObjectPeerTest` to test this with a `Filter`.
---

diff --git a/gen_type_mapping.py b/gen_type_mapping.py
index cffdc839..39ee2605 100644
--- a/gen_type_mapping.py
+++ b/gen_type_mapping.py
@@ -371,6 +371,7 @@ class TypeMappingGenerator:
                     # underlying unlike Vecs, and it gives Java more freedom.
                     base_conv = base_conv + "\nFREE((void*)" + ty_info.var_name + ");"
                 if ty_info.rust_obj in self.complex_enums:
+                    to_hu_conv_sfx = ""
                     if needs_full_clone and (ty_info.rust_obj.replace("LDK", "") + "_clone") not in self.clone_fns:
                         # We really need a full clone here, but for now we just implement
                         # a manual clone explicitly for Option<Trait>s
@@ -378,6 +379,7 @@ class TypeMappingGenerator:
                             assert ty_info.rust_obj.startswith("LDKCOption") # We don't support contained traits for anything else yet
                             optional_ty = ty_info.rust_obj[11:-1]
                             assert "LDK" + optional_ty in self.trait_structs # We don't support contained traits for anything else yet
+                            to_hu_conv_sfx = "this.ptrs_to.add(" + ty_info.var_name + ")"
                             base_conv += "\nif (" + ty_info.var_name + "_conv.tag == " + ty_info.rust_obj + "_Some) {"
                             base_conv += "\n\t// Manually implement clone for Java trait instances"
                             optional_ty_info = self.java_c_types("LDK" + optional_ty + " " + ty_info.var_name, None)
@@ -393,7 +395,7 @@ class TypeMappingGenerator:
                         arg_conv = base_conv, arg_conv_name = ty_info.var_name + "_conv", arg_conv_cleanup = None,
                         ret_conv = ret_conv, ret_conv_name = ty_info.var_name + "_ref",
                         to_hu_conv = ty_info.java_hu_ty + " " + ty_info.var_name + "_hu_conv = " + ty_info.java_hu_ty + ".constr_from_ptr(" + ty_info.var_name + ");\n" + ty_info.var_name + "_hu_conv.ptrs_to.add(this);",
-                        to_hu_conv_name = ty_info.var_name + "_hu_conv", from_hu_conv = (ty_info.var_name + ".ptr", ""))
+                        to_hu_conv_name = ty_info.var_name + "_hu_conv", from_hu_conv = (ty_info.var_name + ".ptr", to_hu_conv_sfx))
                 if ty_info.rust_obj in self.result_types:
                     if holds_ref:
                         # If we're trying to return a ref, we have to clone.
diff --git a/src/test/java/org/ldk/HumanObjectPeerTest.java b/src/test/java/org/ldk/HumanObjectPeerTest.java
index a123b6e3..b51df842 100644
--- a/src/test/java/org/ldk/HumanObjectPeerTest.java
+++ b/src/test/java/org/ldk/HumanObjectPeerTest.java
@@ -174,7 +174,7 @@ class HumanObjectPeerTestInstance {
         NetGraphMsgHandler route_handler;
         final Watch chain_watch;
         final HashSet<String> filter_additions;
-        final Option_FilterZ filter;
+        Option_FilterZ filter;
         ChannelManager chan_manager;
         PeerManager peer_manager;
         final HashMap<String, ChannelMonitor> monitors; // Wow I forgot just how terrible Java is - we can't put a byte array here.
@@ -387,6 +387,7 @@ class HumanObjectPeerTestInstance {
             }
 
             this.node_id = chan_manager.get_our_node_id();
+            this.filter = null;
             bind_nio();
             System.gc();
         }
@@ -493,6 +494,7 @@ class HumanObjectPeerTestInstance {
                 // the ChannelSigner.
                 this.ptr_to = orig.chan_manager;
             }
+            this.filter = null;
         }
 
         TwoTuple_TxidCVec_C2Tuple_u32TxOutZZZ[] connect_block(Block b, int height, long expected_monitor_update_len) {