Add runtime setting to suppress leak warnings

README.md

@@ -203,7 +203,9 @@ improvements for developers:
 
 - When the python interpreter shuts down, _nanobind_ reports instance, type,
   and function leaks related to bindings, which is useful for tracking down
-  reference counting issues.
+  reference counting issues.  
+  If these warnings are undesired, call `nb::set_leak_warnings(false)` from
+  any one of the loaded extension modules.
 
 - _nanobind_ deletes its internal data structures when the Python interpreter
   terminates, which avoids memory leak reports in tools like _valgrind_.

include/nanobind/nb_lib.h

@@ -406,5 +406,9 @@ NB_CORE void incref_checked(PyObject *o) noexcept;
 /// Decrease the reference count of 'o', and check that the GIL is held
 NB_CORE void decref_checked(PyObject *o) noexcept;
 
+// ========================================================================
+
+NB_CORE void set_leak_warnings(bool print_leak_warnings) noexcept;
+
 NAMESPACE_END(detail)
 NAMESPACE_END(NB_NAMESPACE)

include/nanobind/nb_misc.h

@@ -54,4 +54,6 @@ template <typename T> struct deleter {
     PyObject *o{nullptr};
 };
 
+void set_leak_warnings(bool print_leak_warnings) noexcept;
+
 NAMESPACE_END(NB_NAMESPACE)

src/common.cpp

@@ -865,7 +865,6 @@ bool load_i64(PyObject *o, uint8_t flags, int64_t *out) noexcept {
     return load_int(o, flags, out);
 }
 
-
 // ========================================================================
 
 void incref_checked(PyObject *o) noexcept {
@@ -886,5 +885,17 @@ void decref_checked(PyObject *o) noexcept {
     Py_DECREF(o);
 }
 
+// ========================================================================
+
+void set_leak_warnings(bool print_leak_warnings) noexcept {
+    nb_internals &internals = internals_get();
+    internals.print_leak_warnings = print_leak_warnings;
+}
+
 NAMESPACE_END(detail)
+
+void set_leak_warnings(bool print_leak_warnings) noexcept {
+    detail::set_leak_warnings(print_leak_warnings);
+}
+
 NAMESPACE_END(NB_NAMESPACE)

src/nb_internals.cpp

@@ -325,41 +325,49 @@ static void internals_cleanup() {
     bool leak = false;
 
     if (!internals_p->inst_c2p.empty()) {
-        fprintf(stderr, "nanobind: leaked %zu instances!\n",
-                internals_p->inst_c2p.size());
+        if (internals_p->print_leak_warnings) {
+            fprintf(stderr, "nanobind: leaked %zu instances!\n",
+                    internals_p->inst_c2p.size());
+        }
         leak = true;
     }
 
     if (!internals_p->keep_alive.empty()) {
-        fprintf(stderr, "nanobind: leaked %zu keep_alive records!\n",
-                internals_p->keep_alive.size());
+        if (internals_p->print_leak_warnings) {
+            fprintf(stderr, "nanobind: leaked %zu keep_alive records!\n",
+                    internals_p->keep_alive.size());
+        }
         leak = true;
     }
 
     if (!internals_p->type_c2p.empty()) {
-        fprintf(stderr, "nanobind: leaked %zu types!\n",
-                internals_p->type_c2p.size());
-        int ctr = 0;
-        for (const auto &kv : internals_p->type_c2p) {
-            fprintf(stderr, " - leaked type \"%s\"\n", kv.second->name);
-            if (ctr++ == 10) {
-                fprintf(stderr, " - ... skipped remainder\n");
-                break;
+        if (internals_p->print_leak_warnings) {
+            fprintf(stderr, "nanobind: leaked %zu types!\n",
+                    internals_p->type_c2p.size());
+            int ctr = 0;
+            for (const auto &kv : internals_p->type_c2p) {
+                fprintf(stderr, " - leaked type \"%s\"\n", kv.second->name);
+                if (ctr++ == 10) {
+                    fprintf(stderr, " - ... skipped remainder\n");
+                    break;
+                }
             }
         }
         leak = true;
     }
 
     if (!internals_p->funcs.empty()) {
-        fprintf(stderr, "nanobind: leaked %zu functions!\n",
-                internals_p->funcs.size());
-        int ctr = 0;
-        for (void *f : internals_p->funcs) {
-            fprintf(stderr, " - leaked function \"%s\"\n",
-                    nb_func_data(f)->name);
-            if (ctr++ == 10) {
-                fprintf(stderr, " - ... skipped remainder\n");
-                break;
+        if (internals_p->print_leak_warnings) {
+            fprintf(stderr, "nanobind: leaked %zu functions!\n",
+                    internals_p->funcs.size());
+            int ctr = 0;
+            for (void *f : internals_p->funcs) {
+                fprintf(stderr, " - leaked function \"%s\"\n",
+                        nb_func_data(f)->name);
+                if (ctr++ == 10) {
+                    fprintf(stderr, " - ... skipped remainder\n");
+                    break;
+                }
             }
         }
         leak = true;
@@ -369,8 +377,10 @@ static void internals_cleanup() {
         delete internals_p;
         internals_p = nullptr;
     } else {
-        fprintf(stderr, "nanobind: this is likely caused by a reference "
-                        "counting issue in the binding code.\n");
+        if (internals_p->print_leak_warnings) {
+            fprintf(stderr, "nanobind: this is likely caused by a reference "
+                            "counting issue in the binding code.\n");
+        }
 
 #if NB_ABORT_ON_LEAK == 1
         abort(); // Extra-strict behavior for the CI server

src/nb_internals.h

@@ -200,6 +200,9 @@ struct nb_internals {
 
     /// Registered C++ -> Python exception translators
     std::vector<std::pair<exception_translator, void *>> exception_translators;
+
+    /// Boolean specifying whether to print leak warnings on exit
+    bool print_leak_warnings{true};
 };
 
 struct current_method {