pythongh-101865: Remove deprecated co_lnotab from code objects as p…

…er PEP626

Doc/library/inspect.rst

@@ -164,10 +164,6 @@ attributes (see :ref:`import-mod-attrs` for module attributes):
 |           |                   | read more :ref:`here      |
 |           |                   | <inspect-module-co-flags>`|
 +-----------+-------------------+---------------------------+
-|           | co_lnotab         | encoded mapping of line   |
-|           |                   | numbers to bytecode       |
-|           |                   | indices                   |
-+-----------+-------------------+---------------------------+
 |           | co_freevars       | tuple of names of free    |
 |           |                   | variables (referenced via |
 |           |                   | a function's closure)     |

Doc/reference/datamodel.rst

@@ -962,7 +962,6 @@ Internal types
          single: co_filename (code object attribute)
          single: co_firstlineno (code object attribute)
          single: co_flags (code object attribute)
-         single: co_lnotab (code object attribute)
          single: co_name (code object attribute)
          single: co_names (code object attribute)
          single: co_nlocals (code object attribute)
@@ -989,9 +988,7 @@ Internal types
       a tuple containing the literals used by the bytecode; :attr:`co_names` is
       a tuple containing the names used by the bytecode; :attr:`co_filename` is
       the filename from which the code was compiled; :attr:`co_firstlineno` is
-      the first line number of the function; :attr:`co_lnotab` is a string
-      encoding the mapping from bytecode offsets to line numbers (for details
-      see the source code of the interpreter); :attr:`co_stacksize` is the
+      the first line number of the function; :attr:`co_stacksize` is the
       required stack size; :attr:`co_flags` is an integer encoding a number
       of flags for the interpreter.
 

Doc/whatsnew/3.12.rst

@@ -700,6 +700,10 @@ Removed
   *context* parameter instead.
   (Contributed by Victor Stinner in :gh:`94172`.)
 
+* Remove ``co_lnotab`` attribute from code objects per :pep:`626`:
+  use ``co_lines`` method instead.
+  (Contributed by Nikita Sobolev in :gh:`101865`.)
+
 
 Porting to Python 3.12
 ======================

Lib/inspect.py

@@ -499,7 +499,6 @@ def iscode(object):
         co_freevars         tuple of names of free variables
         co_posonlyargcount  number of positional only arguments
         co_kwonlyargcount   number of keyword only arguments (not including ** arg)
-        co_lnotab           encoded mapping of line numbers to bytecode indices
         co_name             name with which this code object was defined
         co_names            tuple of names other than arguments and function locals
         co_nlocals          number of local variables
@@ -1708,7 +1707,6 @@ def getframeinfo(frame, context=1):
 
 def getlineno(frame):
     """Get the line number from a frame object, allowing for optimization."""
-    # FrameType.f_lineno is now a descriptor that grovels co_lnotab
     return frame.f_lineno
 
 _FrameInfo = namedtuple('_FrameInfo', ('frame',) + Traceback._fields)

Lib/pydoc_data/topics.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# Autogenerated by Sphinx on Tue Feb  7 13:18:04 2023
+# Autogenerated by Sphinx on Mon Feb 13 10:21:05 2023
 topics = {'assert': 'The "assert" statement\n'
            '**********************\n'
            '\n'
@@ -13704,13 +13704,10 @@
           '      bytecode; "co_filename" is the filename from which the code '
           'was\n'
           '      compiled; "co_firstlineno" is the first line number of the\n'
-          '      function; "co_lnotab" is a string encoding the mapping from\n'
-          '      bytecode offsets to line numbers (for details see the source\n'
-          '      code of the interpreter); "co_stacksize" is the required '
-          'stack\n'
-          '      size; "co_flags" is an integer encoding a number of flags '
-          'for\n'
-          '      the interpreter.\n'
+          '      function; "co_stacksize" is the required stack size; '
+          '"co_flags"\n'
+          '      is an integer encoding a number of flags for the '
+          'interpreter.\n'
           '\n'
           '      The following flag bits are defined for "co_flags": bit '
           '"0x04"\n'

Misc/NEWS.d/next/Core and Builtins/2023-02-13-10-35-52.gh-issue-101865.2kjTxP.rst

@@ -0,0 +1 @@
+Remove deprecated ``co_lnotab`` from code objects as per :pep:`626`.

Misc/gdbinit

@@ -54,25 +54,7 @@ end
 # A rewrite of the Python interpreter's line number calculator in GDB's
 # command language
 define lineno
-    set $__continue = 1
-    set $__co = f->f_code
-    set $__lasti = f->f_lasti
-    set $__sz = ((PyVarObject *)$__co->co_lnotab)->ob_size/2
-    set $__p = (unsigned char *)((PyBytesObject *)$__co->co_lnotab)->ob_sval
-    set $__li = $__co->co_firstlineno
-    set $__ad = 0
-    while ($__sz-1 >= 0 && $__continue)
-      set $__sz = $__sz - 1
-      set $__ad = $__ad + *$__p
-      set $__p = $__p + 1
-      if ($__ad > $__lasti)
-	set $__continue = 0
-      else
-        set $__li = $__li + *$__p
-        set $__p = $__p + 1
-      end
-    end
-    printf "%d", $__li
+    printf "%d", f->f_lineno
 end
 
 define pyframev

Objects/codeobject.c

@@ -1097,77 +1097,6 @@ _PyLineTable_NextAddressRange(PyCodeAddressRange *range)
     return 1;
 }
 
-static int
-emit_pair(PyObject **bytes, int *offset, int a, int b)
-{
-    Py_ssize_t len = PyBytes_GET_SIZE(*bytes);
-    if (*offset + 2 >= len) {
-        if (_PyBytes_Resize(bytes, len * 2) < 0)
-            return 0;
-    }
-    unsigned char *lnotab = (unsigned char *) PyBytes_AS_STRING(*bytes);
-    lnotab += *offset;
-    *lnotab++ = a;
-    *lnotab++ = b;
-    *offset += 2;
-    return 1;
-}
-
-static int
-emit_delta(PyObject **bytes, int bdelta, int ldelta, int *offset)
-{
-    while (bdelta > 255) {
-        if (!emit_pair(bytes, offset, 255, 0)) {
-            return 0;
-        }
-        bdelta -= 255;
-    }
-    while (ldelta > 127) {
-        if (!emit_pair(bytes, offset, bdelta, 127)) {
-            return 0;
-        }
-        bdelta = 0;
-        ldelta -= 127;
-    }
-    while (ldelta < -128) {
-        if (!emit_pair(bytes, offset, bdelta, -128)) {
-            return 0;
-        }
-        bdelta = 0;
-        ldelta += 128;
-    }
-    return emit_pair(bytes, offset, bdelta, ldelta);
-}
-
-static PyObject *
-decode_linetable(PyCodeObject *code)
-{
-    PyCodeAddressRange bounds;
-    PyObject *bytes;
-    int table_offset = 0;
-    int code_offset = 0;
-    int line = code->co_firstlineno;
-    bytes = PyBytes_FromStringAndSize(NULL, 64);
-    if (bytes == NULL) {
-        return NULL;
-    }
-    _PyCode_InitAddressRange(code, &bounds);
-    while (_PyLineTable_NextAddressRange(&bounds)) {
-        if (bounds.opaque.computed_line != line) {
-            int bdelta = bounds.ar_start - code_offset;
-            int ldelta = bounds.opaque.computed_line - line;
-            if (!emit_delta(&bytes, bdelta, ldelta, &table_offset)) {
-                Py_DECREF(bytes);
-                return NULL;
-            }
-            code_offset = bounds.ar_start;
-            line = bounds.opaque.computed_line;
-        }
-    }
-    _PyBytes_Resize(&bytes, table_offset);
-    return bytes;
-}
-
 
 typedef struct {
     PyObject_HEAD
@@ -1881,12 +1810,6 @@ static PyMemberDef code_memberlist[] = {
 };
 
 
-static PyObject *
-code_getlnotab(PyCodeObject *code, void *closure)
-{
-    return decode_linetable(code);
-}
-
 static PyObject *
 code_getvarnames(PyCodeObject *code, void *closure)
 {
@@ -1919,7 +1842,6 @@ code_getcode(PyCodeObject *code, void *closure)
 }
 
 static PyGetSetDef code_getsetlist[] = {
-    {"co_lnotab",         (getter)code_getlnotab,       NULL, NULL},
     {"_co_code_adaptive", (getter)code_getcodeadaptive, NULL, NULL},
     // The following old names are kept for backward compatibility.
     {"co_varnames",       (getter)code_getvarnames,     NULL, NULL},