Fix reference leaks in blob filter stream and _cache_enums

Fixes #1481.

Assisted-by: Kimi Code

Author: jdavid

CHANGELOG.md

@@ -25,6 +25,10 @@
   `Tree.diff_to_index()` on early error paths
   [#1480](https://github.com/libgit2/pygit2/issues/1480).
 
+- Fix reference leaks in the blob filter stream callbacks and in
+  `_cache_enums()`
+  [#1481](https://github.com/libgit2/pygit2/issues/1481).
+
 
 # 1.20.0 (2026-08-08)
 

src/blob.c

@@ -190,6 +190,7 @@ static int blob_filter_stream_write(
             err = GIT_ERROR;
             goto done;
         }
+        Py_DECREF(result);
         pos += chunk_size;
     }
 
@@ -202,7 +203,7 @@ static int blob_filter_stream_close(git_writestream *s)
 {
     struct blob_filter_stream *stream = (struct blob_filter_stream *)s;
     PyGILState_STATE gil = PyGILState_Ensure();
-    PyObject *result;
+    PyObject *result = NULL;
     int err = 0;
 
     /* Signal closed and then ready in that order so consumers can block on
@@ -214,13 +215,15 @@ static int blob_filter_stream_close(git_writestream *s)
         git_error_set(GIT_ERROR_OS, "failed to signal writer closed");
         err = GIT_ERROR;
     }
+    Py_XDECREF(result);
     result = PyObject_CallMethod(stream->py_ready, "set", NULL);
     if (result == NULL)
     {
         PyErr_Clear();
         git_error_set(GIT_ERROR_OS, "failed to signal queue ready");
         err = GIT_ERROR;
     }
+    Py_XDECREF(result);
 
     PyGILState_Release(gil);
     return err;

src/pygit2.c

@@ -407,6 +407,7 @@ _cache_enums(PyObject *self, PyObject *args)
 
 #undef CACHE_PYGIT2_ENUM
 
+    Py_DECREF(enums);
     Py_RETURN_NONE;
 
 fail: