Merge branch 'main' into pythongh-119726-generate-and-patch-AArch64-t…

…rampolines

Doc/c-api/buffer.rst

@@ -244,7 +244,6 @@ The following fields are not influenced by *flags* and must always be filled in
 with the correct values: :c:member:`~Py_buffer.obj`, :c:member:`~Py_buffer.buf`,
 :c:member:`~Py_buffer.len`, :c:member:`~Py_buffer.itemsize`, :c:member:`~Py_buffer.ndim`.
 
-
 readonly, format
 ~~~~~~~~~~~~~~~~
 
@@ -253,7 +252,8 @@ readonly, format
       Controls the :c:member:`~Py_buffer.readonly` field. If set, the exporter
       MUST provide a writable buffer or else report failure. Otherwise, the
       exporter MAY provide either a read-only or writable buffer, but the choice
-      MUST be consistent for all consumers.
+      MUST be consistent for all consumers. For example, :c:expr:`PyBUF_SIMPLE | PyBUF_WRITABLE`
+      can be used to request a simple writable buffer.
 
    .. c:macro:: PyBUF_FORMAT
 
@@ -265,8 +265,9 @@ readonly, format
 Since :c:macro:`PyBUF_SIMPLE` is defined as 0, :c:macro:`PyBUF_WRITABLE`
 can be used as a stand-alone flag to request a simple writable buffer.
 
-:c:macro:`PyBUF_FORMAT` can be \|'d to any of the flags except :c:macro:`PyBUF_SIMPLE`.
-The latter already implies format ``B`` (unsigned bytes).
+:c:macro:`PyBUF_FORMAT` must be \|'d to any of the flags except :c:macro:`PyBUF_SIMPLE`, because
+the latter already implies format ``B`` (unsigned bytes). :c:macro:`!PyBUF_FORMAT` cannot be
+used on its own.
 
 
 shape, strides, suboffsets

Doc/library/dis.rst

@@ -312,7 +312,8 @@ operation is being performed, so the intermediate analysis object isn't useful:
    .. versionchanged:: 3.14
       Added the *show_positions* parameter.
 
-.. function:: disassemble(code, lasti=-1, *, file=None, show_caches=False, adaptive=False)
+.. function:: disassemble(code, lasti=-1, *, file=None, show_caches=False,\
+                          adaptive=False, show_offsets=False, show_positions=False)
               disco(code, lasti=-1, *, file=None, show_caches=False, adaptive=False,\
                     show_offsets=False, show_positions=False)
 

Doc/library/tomllib.rst

@@ -13,7 +13,7 @@
 
 --------------
 
-This module provides an interface for parsing TOML (Tom's Obvious Minimal
+This module provides an interface for parsing TOML 1.0.0 (Tom's Obvious Minimal
 Language, `https://toml.io <https://toml.io/en/>`_). This module does not
 support writing TOML.
 

Doc/whatsnew/3.14.rst

@@ -70,6 +70,21 @@ Summary -- Release highlights
 New Features
 ============
 
+Improved Error Messages
+-----------------------
+
+* When unpacking assignment fails due to incorrect number of variables, the
+  error message prints the received number of values in more cases than before.
+  (Contributed by Tushar Sadhwani in :gh:`122239`.)
+
+  .. code-block:: pycon
+
+     >>> x, y, z = 1, 2, 3, 4
+     Traceback (most recent call last):
+       File "<stdin>", line 1, in <module>
+         x, y, z = 1, 2, 3, 4
+         ^^^^^^^
+     ValueError: too many values to unpack (expected 3, got 4)
 
 
 Other Language Changes

Lib/test/test_unpack.py

@@ -18,6 +18,13 @@
     >>> a == 4 and b == 5 and c == 6
     True
 
+Unpack dict
+
+    >>> d = {4: 'four', 5: 'five', 6: 'six'}
+    >>> a, b, c = d
+    >>> a == 4 and b == 5 and c == 6
+    True
+
 Unpack implied tuple
 
     >>> a, b, c = 7, 8, 9
@@ -66,14 +73,14 @@
     >>> a, b = t
     Traceback (most recent call last):
       ...
-    ValueError: too many values to unpack (expected 2)
+    ValueError: too many values to unpack (expected 2, got 3)
 
 Unpacking tuple of wrong size
 
     >>> a, b = l
     Traceback (most recent call last):
       ...
-    ValueError: too many values to unpack (expected 2)
+    ValueError: too many values to unpack (expected 2, got 3)
 
 Unpacking sequence too short
 
@@ -140,8 +147,52 @@
     >>> () = [42]
     Traceback (most recent call last):
       ...
-    ValueError: too many values to unpack (expected 0)
+    ValueError: too many values to unpack (expected 0, got 1)
+
+Unpacking a larger iterable should raise ValuleError, but it
+should not entirely consume the iterable
 
+    >>> it = iter(range(100))
+    >>> x, y, z = it
+    Traceback (most recent call last):
+      ...
+    ValueError: too many values to unpack (expected 3)
+    >>> next(it)
+    4
+
+Unpacking unbalanced dict
+
+    >>> d = {4: 'four', 5: 'five', 6: 'six', 7: 'seven'}
+    >>> a, b, c = d
+    Traceback (most recent call last):
+      ...
+    ValueError: too many values to unpack (expected 3, got 4)
+
+Ensure that custom `__len__()` is NOT called when showing the error message
+
+    >>> class LengthTooLong:
+    ...     def __len__(self):
+    ...         return 5
+    ...     def __getitem__(self, i):
+    ...         return i*2
+    ...
+    >>> x, y, z = LengthTooLong()
+    Traceback (most recent call last):
+      ...
+    ValueError: too many values to unpack (expected 3)
+
+For evil cases like these as well, no actual count to be shown
+
+    >>> class BadLength:
+    ...     def __len__(self):
+    ...         return 1
+    ...     def __getitem__(self, i):
+    ...         return i*2
+    ...
+    >>> x, y, z = BadLength()
+    Traceback (most recent call last):
+      ...
+    ValueError: too many values to unpack (expected 3)
 """
 
 __test__ = {'doctests' : doctests}

Misc/NEWS.d/next/Core_and_Builtins/2024-07-25-01-45-21.gh-issue-122239.7zh-sW.rst

@@ -0,0 +1,3 @@
+When a :class:`list`, :class:`tuple` or :class:`dict`
+with too many elements is unpacked, show the actual
+length in the error message.

Python/ceval.c

@@ -2148,6 +2148,17 @@ _PyEval_UnpackIterableStackRef(PyThreadState *tstate, _PyStackRef v_stackref,
             return 1;
         }
         Py_DECREF(w);
+
+        if (PyList_CheckExact(v) || PyTuple_CheckExact(v)
+              || PyDict_CheckExact(v)) {
+            ll = PyDict_CheckExact(v) ? PyDict_Size(v) : Py_SIZE(v);
+            if (ll > argcnt) {
+                _PyErr_Format(tstate, PyExc_ValueError,
+                              "too many values to unpack (expected %d, got %zd)",
+                              argcnt, ll);
+                goto Error;
+            }
+        }
         _PyErr_Format(tstate, PyExc_ValueError,
                       "too many values to unpack (expected %d)",
                       argcnt);