Fix a memory leak for WBuffers used in channel_write().

channel_write() uses a ref-counted buffer for writing. This buffer
should be released if it was used in "refcount" channel_write() calls.
But calling channel_write() on a closed channel would return early and
not decrease the refcount of the used buffer.

2 files changed, 4 insertions, 3 deletions

diff --git a/src/nvim/msgpack_rpc/channel.c b/src/nvim/msgpack_rpc/channel.c
index ab67500fdc..35549ce042 100644
--- a/src/nvim/msgpack_rpc/channel.c
+++ b/src/nvim/msgpack_rpc/channel.c
@@ -495,6 +495,7 @@ static bool channel_write(Channel *channel, WBuffer *buffer)
   bool success;
 
   if (channel->closed) {
+    wstream_release_wbuffer(buffer);
     return false;
   }
 
diff --git a/src/nvim/os/wstream.c b/src/nvim/os/wstream.c
index 90d4ebeec8..13c6c0429f 100644
--- a/src/nvim/os/wstream.c
+++ b/src/nvim/os/wstream.c
@@ -181,7 +181,7 @@ bool wstream_write(WStream *wstream, WBuffer *buffer)
   return true;
 
 err:
-  release_wbuffer(buffer);
+  wstream_release_wbuffer(buffer);
   return false;
 }
 
@@ -217,7 +217,7 @@ static void write_cb(uv_write_t *req, int status)
 
   data->wstream->curmem -= data->buffer->size;
 
-  release_wbuffer(data->buffer);
+  wstream_release_wbuffer(data->buffer);
 
   if (data->wstream->cb) {
     data->wstream->cb(data->wstream,
@@ -239,7 +239,7 @@ static void write_cb(uv_write_t *req, int status)
   kmp_free(WRequestPool, wrequest_pool, data);
 }
 
-static void release_wbuffer(WBuffer *buffer)
+void wstream_release_wbuffer(WBuffer *buffer)
 {
   if (!--buffer->refcount) {
     if (buffer->cb) {