fix posting list merge operator in batch_merge, bump to 2.4.1

- Fix atom comparison in ParseOperand to use enif_is_identical() instead
  of direct == comparison. Atoms decoded via enif_binary_to_term require
  proper NIF comparison functions.
- Add posting_list_batch_merge_test to verify batch operations work correctly

Author: benoitc

CHANGELOG.md

@@ -1,3 +1,12 @@
+## erlang-rocksdb 2.4.1, released on 2026/01/04
+
+### Bug Fixes
+
+- fix posting list merge operator not recognizing operands in `batch_merge`:
+  - Fixed atom comparison in `ParseOperand` to use `enif_is_identical()` instead of direct `==` comparison
+  - Atoms decoded via `enif_binary_to_term` require proper NIF comparison functions
+  - Added `posting_list_batch_merge_test` to verify batch operations work correctly
+
 ## erlang-rocksdb 2.4.0, released on 2026/01/04
 
 ### New Features

README.md

@@ -3,7 +3,7 @@
 [![Build Status](https://github.com/EnkiMultimedia/erlang-rocksdb/workflows/build/badge.svg)](https://github.com/EnkiMultimedia/erlang-rocksdb/actions?query=workflow%3Abuild)
 [![Hex pm](http://img.shields.io/hexpm/v/rocksdb.svg?style=flat)](https://hex.pm/packages/rocksdb)
 
-**Current version: 2.4.0**
+**Current version: 2.4.1**
 
 Copyright (c) 2016-2026 Benoît Chesneau
 

c_src/posting_list_merge_operator.cc

@@ -125,9 +125,9 @@ namespace erocksdb {
             return false;
         }
 
-        if (tuple[0] == ATOM_POSTING_ADD) {
+        if (enif_is_identical(tuple[0], ATOM_POSTING_ADD)) {
             is_tombstone = false;
-        } else if (tuple[0] == ATOM_POSTING_DELETE) {
+        } else if (enif_is_identical(tuple[0], ATOM_POSTING_DELETE)) {
             is_tombstone = true;
         } else {
             enif_free_env(env);

src/rocksdb.app.src

@@ -17,7 +17,7 @@
 {application, rocksdb,
  [
   {description, "RocksDB for Erlang"},
-  {vsn, "2.4.0"},
+  {vsn, "2.4.1"},
   {registered, []},
   {applications, [
           kernel,

test/posting_list.erl

@@ -76,6 +76,47 @@ posting_list_delete_test() ->
     rocksdb:destroy(DbPath, []),
     rocksdb_test_util:rm_rf(DbPath).
 
+posting_list_batch_merge_test() ->
+    DbPath = "posting_list_batch_merge.test",
+    rocksdb_test_util:rm_rf(DbPath),
+    {ok, Db} = rocksdb:open(DbPath, [
+        {create_if_missing, true},
+        {merge_operator, posting_list_merge_operator}
+    ]),
+
+    %% Create a batch with posting list operations
+    {ok, Batch} = rocksdb:batch(),
+    ok = rocksdb:batch_merge(Batch, <<"term1">>, {posting_add, <<"doc1">>}),
+    ok = rocksdb:batch_merge(Batch, <<"term1">>, {posting_add, <<"doc2">>}),
+    ok = rocksdb:batch_merge(Batch, <<"term1">>, {posting_add, <<"doc3">>}),
+    ok = rocksdb:batch_merge(Batch, <<"term2">>, {posting_add, <<"doc1">>}),
+    ok = rocksdb:batch_merge(Batch, <<"term2">>, {posting_add, <<"doc2">>}),
+    %% Delete doc2 from term1 in the same batch
+    ok = rocksdb:batch_merge(Batch, <<"term1">>, {posting_delete, <<"doc2">>}),
+
+    %% Write the batch
+    ok = rocksdb:write_batch(Db, Batch, []),
+    ok = rocksdb:release_batch(Batch),
+
+    %% Verify term1: should have doc1 and doc3 (doc2 was deleted)
+    {ok, Bin1} = rocksdb:get(Db, <<"term1">>, []),
+    Keys1 = rocksdb:posting_list_keys(Bin1),
+    ?assert(lists:member(<<"doc1">>, Keys1)),
+    ?assertNot(lists:member(<<"doc2">>, Keys1)),
+    ?assert(lists:member(<<"doc3">>, Keys1)),
+    ?assertEqual(2, rocksdb:posting_list_count(Bin1)),
+
+    %% Verify term2: should have doc1 and doc2
+    {ok, Bin2} = rocksdb:get(Db, <<"term2">>, []),
+    Keys2 = rocksdb:posting_list_keys(Bin2),
+    ?assert(lists:member(<<"doc1">>, Keys2)),
+    ?assert(lists:member(<<"doc2">>, Keys2)),
+    ?assertEqual(2, rocksdb:posting_list_count(Bin2)),
+
+    ok = rocksdb:close(Db),
+    rocksdb:destroy(DbPath, []),
+    rocksdb_test_util:rm_rf(DbPath).
+
 posting_list_compaction_test() ->
     %% Test that merge operator cleans up tombstones during merge
     %% Tombstones are removed during reads (FullMergeV2) and compaction (PartialMergeMulti)