https://github.com/python/cpython/commit/db85e76dc234186984c0cf795cde314e1cde845e
commit: db85e76dc234186984c0cf795cde314e1cde845e
branch: 3.15
author: Victor Stinner <[email protected]>
committer: vstinner <[email protected]>
date: 2026-10-16T22:33:06Z
summary:
[3.15] gh-158585: Backport test_capi.test_bytes from main (#159588)
gh-158585: Backport test_capi.test_bytes from main
Backport also _testcapi.call_with_nomemory().
files:
M Lib/test/test_capi/test_bytes.py
M Modules/_testcapi/mem.c
diff --git a/Lib/test/test_capi/test_bytes.py b/Lib/test/test_capi/test_bytes.py
index 6c193e10bd222e..20d5af9c55713c 100644
--- a/Lib/test/test_capi/test_bytes.py
+++ b/Lib/test/test_capi/test_bytes.py
@@ -59,10 +59,12 @@ def test_fromstringandsize(self):
self.assertEqual(fromstringandsize(b'abc'), b'abc')
self.assertEqual(fromstringandsize(b'abc', 2), b'ab')
self.assertEqual(fromstringandsize(b'abc\0def'), b'abc\0def')
- self.assertEqual(fromstringandsize(b'a'), b'a')
- self.assertEqual(fromstringandsize(b'a', 1), b'a')
- self.assertEqual(fromstringandsize(b'', 0), b'')
- self.assertEqual(fromstringandsize(NULL, 0), b'')
+
+ # Return singleton for 0 or 1 bytes
+ self.assertIs(fromstringandsize(b'', 0), b'')
+ self.assertIs(fromstringandsize(NULL, 0), b'')
+ self.assertIs(fromstringandsize(b'a', 1), b'a')
+
self.assertEqual(len(fromstringandsize(NULL, 3)), 3)
self.assertRaises((MemoryError, OverflowError),
fromstringandsize, NULL, PY_SSIZE_T_MAX)
@@ -77,7 +79,10 @@ def test_fromstring(self):
fromstring = _testlimitedcapi.bytes_fromstring
self.assertEqual(fromstring(b'abc\0def'), b'abc')
- self.assertEqual(fromstring(b''), b'')
+
+ # Return singleton for 0 or 1 bytes
+ self.assertIs(fromstring(b''), b'')
+ self.assertIs(fromstring(b'a'), b'a')
# CRASHES fromstring(NULL)
@@ -434,7 +439,7 @@ def test_resize(self):
writer = self.create_writer()
writer.resize(len(b'hello'))
writer.write(0, b'hello')
- self.assertEqual(writer.finish(), b'hello')
+ self.bytes_equal(writer.finish(), b'hello')
writer = self.create_writer()
writer.resize(0) # noop
@@ -445,7 +450,7 @@ def test_resize(self):
writer.resize(len(b'number=123'), )
writer.write(len(b'number='), b'123')
writer.resize(len(b'number=123')) # noop
- self.assertEqual(writer.finish(), b'number=123')
+ self.bytes_equal(writer.finish(), b'number=123')
# Switch from small buffer to large buffer
writer = self.create_writer()
@@ -454,7 +459,7 @@ def test_resize(self):
writer.write(0, b's' * small)
writer.resize(large)
writer.write(small, b'L' * (large - small))
- self.assertEqual(writer.finish(),
+ self.bytes_equal(writer.finish(),
b's' * small + b'L' * (large - small))
# Make sure that it's possible to write after a resize to zero
@@ -463,7 +468,7 @@ def test_resize(self):
writer.resize(self.LARGE_BUFFER)
writer.resize(0)
writer.write_bytes(b'abc', 3)
- self.assertEqual(writer.finish(), b'abc')
+ self.bytes_equal(writer.finish(), b'abc')
# invalid size
for size in (self.SMALL_BUFFER, self.LARGE_BUFFER):
@@ -474,7 +479,7 @@ def test_resize(self):
writer.resize(-1)
with self.assertRaises((MemoryError, OverflowError)):
writer.resize(_testcapi.PY_SSIZE_T_MAX)
- self.assertEqual(writer.finish(), b'x' * size)
+ self.bytes_equal(writer.finish(), b'x' * size)
@support.nomemtest
def test_resize_error(self):
@@ -488,7 +493,7 @@ def test_resize_error(self):
writer.resize(size)
suffix = b'still working'
writer.write_bytes(suffix, -1)
- self.assertEqual(writer.finish(), init + suffix)
+ self.bytes_equal(writer.finish(), init + suffix)
# Note: PyBytesWriter_Resize() leaves the buffer unchanged (no resize)
# if the new size is smaller than the allocated size
@@ -498,7 +503,7 @@ def test_grow(self):
writer = self.create_writer(0)
writer.grow(len(b'number=123'))
writer.write(0, b'number=123')
- self.assertEqual(writer.finish(), b'number=123')
+ self.bytes_equal(writer.finish(), b'number=123')
writer = self.create_writer()
writer.grow(0) # noop
@@ -509,25 +514,7 @@ def test_grow(self):
writer.grow(len(b'123'), )
writer.write(len(b'number='), b'123')
writer.grow(0) # noop
- self.assertEqual(writer.finish(), b'number=123')
-
- for size in (self.SMALL_BUFFER, self.LARGE_BUFFER):
- with self.subTest(size=size):
- # Truncate the last byte
- data = b'x' * size
- writer = self.create_writer(size)
- writer.write(0, data)
- self.assertEqual(writer.get_data(), data)
- writer.grow(-1)
- self.assertEqual(writer.get_data(), data[:-1])
- self.assertEqual(writer.finish(), data[:-1])
-
- # Make the buffer empty
- writer = self.create_writer(size)
- writer.write(0, data)
- writer.grow(-size)
- self.assertEqual(writer.get_data(), b'')
- self.assertEqual(writer.finish(), b'')
+ self.bytes_equal(writer.finish(), b'number=123')
# Switch from small buffer to large buffer
writer = self.create_writer()
@@ -536,7 +523,7 @@ def test_grow(self):
writer.write(0, b's' * small)
writer.grow(large - small)
writer.write(small, b'L' * (large - small))
- self.assertEqual(writer.finish(),
+ self.bytes_equal(writer.finish(),
b's' * small + b'L' * (large - small))
# invalid size
@@ -548,7 +535,7 @@ def test_grow(self):
writer.grow(-size - 1)
with self.assertRaises(MemoryError):
writer.grow(_testcapi.PY_SSIZE_T_MAX)
- self.assertEqual(writer.finish(), b'x' * size)
+ self.bytes_equal(writer.finish(), b'x' * size)
@support.nomemtest
def test_grow_error(self):
@@ -574,23 +561,37 @@ def test_format_i(self):
writer = self.create_writer()
writer.format_i(b'x=%i, ', 123)
- writer.format_i(b'y=%i', 456)
+ writer.format_i(b'y=%d', 456)
self.bytes_equal(writer.finish(), b'x=123, y=456')
+ # Test invalid format: "%t" is invalid, stop the parser and copy
+ # remaining bytes
+ writer = self.create_writer()
+ writer.write_bytes(b'prefix ', -1)
+ writer.format_i(b'y=%._ t %i', 0)
+ writer.write_bytes(b'.', 1)
+ self.bytes_equal(writer.finish(), b'prefix y=%._ t %i.')
+
def test_format_s(self):
# Test PyBytesWriter_Format()
writer = self.create_writer()
writer.format_s(b's=%s', b'Hello World')
self.bytes_equal(writer.finish(), b's=Hello World')
+ # Test precision
+ writer = self.create_writer()
+ writer.format_s(b'%.6s', b'Monty Python')
+ writer.format_s(b'%.20s', b'3.0')
+ self.bytes_equal(writer.finish(), b'Monty 3.0')
+
@support.nomemtest
def test_format_s_memory_error(self):
writer = self.create_writer()
- s = b'x' * 500
+ s = b'x' * self.LARGE_BUFFER
with self.assertRaises(MemoryError):
- with support.inject_memory_error_cm():
- writer.format_s(b's=%s', s)
+ _testcapi.call_with_nomemory(0, 0, writer.format_s, b's=%s', s)
writer.write_bytes(b'after', -1)
+ self.bytes_equal(writer.finish(), b'after')
@threading_helper.requires_working_threading()
def test_thread(self):
@@ -620,7 +621,7 @@ def thread_func(writer, LARGE_BUFFER):
self.assertEqual(size, 10)
self.assertEqual(data, b'x' * 10)
- self.assertEqual(writer.finish(), b'x' * 10)
+ self.bytes_equal(writer.finish(), b'x' * 10)
class BytesWriterTest(BaseWriterTest, unittest.TestCase):
diff --git a/Modules/_testcapi/mem.c b/Modules/_testcapi/mem.c
index a4fbf865913c5e..29b2d78603197a 100644
--- a/Modules/_testcapi/mem.c
+++ b/Modules/_testcapi/mem.c
@@ -188,6 +188,39 @@ remove_mem_hooks(PyObject *self, PyObject
*Py_UNUSED(ignored))
Py_RETURN_NONE;
}
+static PyObject *
+call_with_nomemory(PyObject *self, PyObject *args)
+{
+ /* Call func(*args) with memory allocation failing as in set_nomemory().
+ * No bytecode is executed between arming the failure and the call. */
+ Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+ if (nargs < 3) {
+ PyErr_SetString(PyExc_TypeError,
+ "call_with_nomemory() requires at least 3 arguments");
+ return NULL;
+ }
+ int start = PyLong_AsInt(PyTuple_GET_ITEM(args, 0));
+ if (start == -1 && PyErr_Occurred()) {
+ return NULL;
+ }
+ int stop = PyLong_AsInt(PyTuple_GET_ITEM(args, 1));
+ if (stop == -1 && PyErr_Occurred()) {
+ return NULL;
+ }
+ PyObject *func = PyTuple_GET_ITEM(args, 2);
+ /* PyObject_Call() with a prebuilt tuple does not allocate,
+ * unlike PyObject_Vectorcall() for a callee without vectorcall. */
+ PyObject *callargs = PyTuple_GetSlice(args, 3, nargs);
+ if (callargs == NULL) {
+ return NULL;
+ }
+ fm_set_nomemory(start, stop);
+ PyObject *res = PyObject_Call(func, callargs, NULL);
+ fm_remove_hooks();
+ Py_DECREF(callargs);
+ return res;
+}
+
static PyObject *
test_setallocators(PyMemAllocatorDomain domain)
{
@@ -874,6 +907,8 @@ static PyMethodDef test_methods[] = {
PyDoc_STR("Remove memory hooks.")},
{"set_nomemory", set_nomemory,
METH_VARARGS,
PyDoc_STR("set_nomemory(start:int, stop:int = 0)")},
+ {"call_with_nomemory", call_with_nomemory,
METH_VARARGS,
+ PyDoc_STR("call_with_nomemory(start:int, stop:int, func, /, *args)")},
{"test_pymem_alloc0", test_pymem_alloc0,
METH_NOARGS},
{"test_pymem_setallocators", test_pymem_setallocators,
METH_NOARGS},
{"test_pymem_setrawallocators", test_pymem_setrawallocators,
METH_NOARGS},
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