Document the co_lines method on code objects (#113682)

AlexWaygood · hugovk · web-flow · commit f1f839243251 · 2024-01-03T19:29:24.000Z
Co-authored-by: Hugo van Kemenade &lt;hugovk@users.noreply.github.com&gt;
diff --git a/Doc/library/dis.rst b/Doc/library/dis.rst
@@ -342,17 +342,18 @@ operation is being performed, so the intermediate analysis object isn't useful:
 
 .. function:: findlinestarts(code)
 
-   This generator function uses the ``co_lines`` method
-   of the code object *code* to find the offsets which are starts of
+   This generator function uses the :meth:`~codeobject.co_lines` method
+   of the :ref:`code object <code-objects>` *code* to find the offsets which
+   are starts of
    lines in the source code.  They are generated as ``(offset, lineno)`` pairs.
 
    .. versionchanged:: 3.6
       Line numbers can be decreasing. Before, they were always increasing.
 
    .. versionchanged:: 3.10
-      The :pep:`626` ``co_lines`` method is used instead of the
+      The :pep:`626` :meth:`~codeobject.co_lines` method is used instead of the
       :attr:`~codeobject.co_firstlineno` and :attr:`~codeobject.co_lnotab`
-      attributes of the code object.
+      attributes of the :ref:`code object <code-objects>`.
 
    .. versionchanged:: 3.13
       Line numbers can be ``None`` for bytecode that does not map to source lines.
diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
@@ -1219,8 +1219,8 @@ If a code object represents a function, the first item in
 :attr:`~codeobject.co_consts` is
 the documentation string of the function, or ``None`` if undefined.
 
-The :meth:`!co_positions` method
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Methods on code objects
+~~~~~~~~~~~~~~~~~~~~~~~
 
 .. method:: codeobject.co_positions()
 
@@ -1255,6 +1255,41 @@ The :meth:`!co_positions` method
       :option:`-X` ``no_debug_ranges`` command line flag or the :envvar:`PYTHONNODEBUGRANGES`
       environment variable can be used.
 
+.. method:: codeobject.co_lines()
+
+   Returns an iterator that yields information about successive ranges of
+   :term:`bytecode`\s. Each item yielded is a ``(start, end, lineno)``
+   :class:`tuple`:
+
+   * ``start`` (an :class:`int`) represents the offset (inclusive) of the start
+     of the :term:`bytecode` range
+   * ``end`` (an :class:`int`) represents the offset (inclusive) of the end of
+     the :term:`bytecode` range
+   * ``lineno`` is an :class:`int` representing the line number of the
+     :term:`bytecode` range, or ``None`` if the bytecodes in the given range
+     have no line number
+
+   The items yielded generated will have the following properties:
+
+   * The first range yielded will have a ``start`` of 0.
+   * The ``(start, end)`` ranges will be non-decreasing and consecutive. That
+     is, for any pair of :class:`tuple`\s, the ``start`` of the second will be
+     equal to the ``end`` of the first.
+   * No range will be backwards: ``end >= start`` for all triples.
+   * The :class:`tuple` yielded will have ``end`` equal to the size of the
+     :term:`bytecode`.
+
+   Zero-width ranges, where ``start == end``, are allowed. Zero-width ranges
+   are used for lines that are present in the source code, but have been
+   eliminated by the :term:`bytecode` compiler.
+
+   .. versionadded:: 3.10
+
+   .. seealso::
+
+      :pep:`626` - Precise line numbers for debugging and other tools.
+         The PEP that introduced the :meth:`!co_lines` method.
+
 
 .. _frame-objects:
 
diff --git a/Doc/whatsnew/3.10.rst b/Doc/whatsnew/3.10.rst
@@ -402,9 +402,11 @@ Tracing events, with the correct line number, are generated for all lines of cod
 The :attr:`~frame.f_lineno` attribute of frame objects will always contain the
 expected line number.
 
-The :attr:`~codeobject.co_lnotab` attribute of code objects is deprecated and
+The :attr:`~codeobject.co_lnotab` attribute of
+:ref:`code objects <code-objects>` is deprecated and
 will be removed in 3.12.
-Code that needs to convert from offset to line number should use the new ``co_lines()`` method instead.
+Code that needs to convert from offset to line number should use the new
+:meth:`~codeobject.co_lines` method instead.
 
 PEP 634: Structural Pattern Matching
 ------------------------------------
diff --git a/Doc/whatsnew/3.13.rst b/Doc/whatsnew/3.13.rst
@@ -816,7 +816,8 @@ although there is currently no date scheduled for their removal.
 
 * :mod:`!sre_compile`, :mod:`!sre_constants` and :mod:`!sre_parse` modules.
 
-* :attr:`~codeobject.co_lnotab`: use the ``co_lines`` attribute instead.
+* :attr:`codeobject.co_lnotab`: use the :meth:`codeobject.co_lines` method
+  instead.
 
 * :class:`typing.Text` (:gh:`92332`).
 
diff --git a/Misc/NEWS.d/3.12.0a4.rst b/Misc/NEWS.d/3.12.0a4.rst
@@ -147,8 +147,8 @@ clinic.
 .. nonce: yRWQ1y
 .. section: Core and Builtins
 
-Improve the output of ``co_lines`` by emitting only one entry for each line
-range.
+Improve the output of :meth:`codeobject.co_lines` by emitting only one entry
+for each line range.
 
 ..
 
diff --git a/Objects/lnotab_notes.txt b/Objects/lnotab_notes.txt
@@ -60,7 +60,7 @@ Final form:
 Iterating over the table.
 -------------------------
 
-For the `co_lines` attribute we want to emit the full form, omitting the (350, 360, No line number) and empty entries.
+For the `co_lines` method we want to emit the full form, omitting the (350, 360, No line number) and empty entries.
 
 The code is as follows:
 
