bpo-32030: Add pymain_get_global_config() (#4735)

* Py_Main() now starts by reading Py_xxx configuration variables to
  only work on its own private structure, and then later writes back
  the configuration into these variables.
* Replace Py_GETENV() with pymain_get_env_var() which ignores empty
  variables.
* Add _PyCoreConfig.dump_refs
* Add _PyCoreConfig.malloc_stats
* _PyObject_DebugMallocStats() is now responsible to check if debug
  hooks are installed. The function returns 1 if stats were written,
  or 0 if the hooks are disabled. Mark _PyMem_PymallocEnabled() as
  static.

1 files changed, 10 insertions, 2 deletions

diff --git a/Objects/obmalloc.c b/Objects/obmalloc.c
index 7911028..c065541 100644
--- a/Objects/obmalloc.c
+++ b/Objects/obmalloc.c
@@ -379,7 +379,7 @@ _PyMem_DebugEnabled(void)
     return (_PyObject.malloc == _PyMem_DebugMalloc);
 }
 
-int
+static int
 _PyMem_PymallocEnabled(void)
 {
     if (_PyMem_DebugEnabled()) {
@@ -2467,10 +2467,17 @@ pool_is_in_list(const poolp target, poolp list)
 /* Print summary info to "out" about the state of pymalloc's structures.
  * In Py_DEBUG mode, also perform some expensive internal consistency
  * checks.
+ *
+ * Return 0 if the memory debug hooks are not installed or no statistics was
+ * writen into out, return 1 otherwise.
  */
-void
+int
 _PyObject_DebugMallocStats(FILE *out)
 {
+    if (!_PyMem_PymallocEnabled()) {
+        return 0;
+    }
+
     uint i;
     const uint numclasses = SMALL_REQUEST_THRESHOLD >> ALIGNMENT_SHIFT;
     /* # of pools, allocated blocks, and free blocks per class index */
@@ -2603,6 +2610,7 @@ _PyObject_DebugMallocStats(FILE *out)
     total += printone(out, "# bytes lost to quantization", quantization);
     total += printone(out, "# bytes lost to arena alignment", arena_alignment);
     (void)printone(out, "Total", total);
+    return 1;
 }
 
 #endif /* #ifdef WITH_PYMALLOC */