feat(code): add co_qualname field

Author: P403n1x87

Include/cpython/code.h

@@ -75,6 +75,8 @@ struct PyCodeObject {
     PyObject *co_localspluskinds; /* Bytes mapping to local kinds (one byte per variable) */
     PyObject *co_filename;      /* unicode (where it was loaded from) */
     PyObject *co_name;          /* unicode (name, for reference) */
+    PyObject *co_qualname;      /* unicode (qualname, only for code objects created
+                                   by the compiler, otherwise NULL) */
     PyObject *co_linetable;     /* string (encoding addr<->lineno mapping) See
                                    Objects/lnotab_notes.txt for details. */
 

Include/internal/pycore_code.h

@@ -212,6 +212,7 @@ struct _PyCodeConstructor {
     /* metadata */
     PyObject *filename;
     PyObject *name;
+    PyObject *qualname;
     int flags;
 
     /* the code */

Misc/NEWS.d/next/C API/2021-06-28-23-44-47.bpo-44530.qij7YC.rst

@@ -0,0 +1,5 @@
+Added the co_qualname to the PyCodeObject structure to propagate the
+qualified name from the compiler to code objects. Code objects that are
+created manually have this new field set to NULL.
+
+Patch by Gabriele N. Tornetta

Objects/codeobject.c

@@ -296,6 +296,9 @@ init_code(PyCodeObject *co, struct _PyCodeConstructor *con)
     co->co_filename = con->filename;
     Py_INCREF(con->name);
     co->co_name = con->name;
+    if (con->qualname != NULL)
+        Py_INCREF(con->qualname);
+    co->co_qualname = con->qualname;
     co->co_flags = con->flags;
 
     Py_INCREF(con->code);
@@ -351,6 +354,9 @@ _PyCode_New(struct _PyCodeConstructor *con)
     if (PyUnicode_READY(con->name) < 0) {
         return NULL;
     }
+    if (con->qualname != NULL && PyUnicode_READY(con->qualname) < 0) {
+        return NULL;
+    }
     if (PyUnicode_READY(con->filename) < 0) {
         return NULL;
     }
@@ -456,6 +462,7 @@ PyCode_NewWithPosOnlyArgs(int argcount, int posonlyargcount, int kwonlyargcount,
     struct _PyCodeConstructor con = {
         .filename = filename,
         .name = name,
+        .qualname = NULL,
         .flags = flags,
 
         .code = code,
@@ -549,6 +556,7 @@ PyCode_NewEmpty(const char *filename, const char *funcname, int firstlineno)
     struct _PyCodeConstructor con = {
         .filename = filename_ob,
         .name = funcname_ob,
+        .qualname = NULL,
         .code = emptystring,
         .firstlineno = firstlineno,
         .linetable = emptystring,
@@ -1146,6 +1154,7 @@ code_dealloc(PyCodeObject *co)
     Py_XDECREF(co->co_cellvars);
     Py_XDECREF(co->co_filename);
     Py_XDECREF(co->co_name);
+    Py_XDECREF(co->co_qualname);
     Py_XDECREF(co->co_linetable);
     Py_XDECREF(co->co_exceptiontable);
     if (co->co_weakreflist != NULL)

Python/compile.c

@@ -7287,6 +7287,7 @@ makecode(struct compiler *c, struct assembler *a, PyObject *constslist,
     struct _PyCodeConstructor con = {
         .filename = c->c_filename,
         .name = c->u->u_name,
+        .qualname = c->u->u_qualname,
         .flags = flags,
 
         .code = a->a_bytecode,

Python/importlib.h

@@ -1378,6 +1378,7 @@ r_object(RFILE *p)
             struct _PyCodeConstructor con = {
                 .filename = filename,
                 .name = name,
+                .qualname = NULL,
                 .flags = flags,
 
                 .code = code,