[3.10] bpo-46006: Revert "bpo-40521: Per-interpreter interned strings (GH-20085)" (GH-30422) (GH-30425)

This reverts commit ea251806b8dffff11b30d2182af1e589caf88acf.

Keep "assert(interned == NULL);" in _PyUnicode_Fini(), but only for
the main interpreter.

Keep _PyUnicode_ClearInterned() changes avoiding the creation of a
temporary Python list object.

Leave the PyInterpreterState structure unchanged to keep the ABI
backward compatibility with Python 3.10.0: rename the "interned"
member to "unused_interned".

(cherry picked from commit 35d6540c904ef07b8602ff014e520603f84b5886)

1 files changed, 3 insertions, 9 deletions

diff --git a/Include/internal/pycore_interp.h b/Include/internal/pycore_interp.h
index bfd082b..4307b61 100644
--- a/Include/internal/pycore_interp.h
+++ b/Include/internal/pycore_interp.h
@@ -71,15 +71,9 @@ struct _Py_unicode_state {
     PyObject *latin1[256];
     struct _Py_unicode_fs_codec fs_codec;
 
-    /* This dictionary holds all interned unicode strings.  Note that references
-       to strings in this dictionary are *not* counted in the string's ob_refcnt.
-       When the interned string reaches a refcnt of 0 the string deallocation
-       function will delete the reference from this dictionary.
-
-       Another way to look at this is that to say that the actual reference
-       count of a string is:  s->ob_refcnt + (s->state ? 2 : 0)
-    */
-    PyObject *interned;
+    // Unused member kept for ABI backward compatibility with Python 3.10.0:
+    // see bpo-46006.
+    PyObject *unused_interned;
 
     // Unicode identifiers (_Py_Identifier): see _PyUnicode_FromId()
     struct _Py_unicode_ids ids;