Warning "Objects/longobject.c:1186:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]"

[sobolevn]

Bug report

It happens here:

cpython/Objects/longobject.c

Lines 1166 to 1193 in b348313

	#if PY_LITTLE_ENDIAN
	if (little_endian) {
	memcpy(buffer, cv.b, sizeof(cv.b));
	memset((char *)buffer + sizeof(cv.b), fill, n - sizeof(cv.b));
	}
	else {
	unsigned char *b = (unsigned char *)buffer;
	for (Py_ssize_t i = 0; i < n - (int)sizeof(cv.b); ++i) {
	*b++ = fill;
	}
	for (Py_ssize_t i = sizeof(cv.b); i > 0; --i) {
	*b++ = cv.b[i - 1];
	}
	}
	#else
	if (little_endian) {
	unsigned char *b = (unsigned char *)buffer;
	for (Py_ssize_t i = sizeof(cv.b); i > 0; --i) {
	*b++ = cv.b[i - 1];
	}
	for (Py_ssize_t i = 0; i < n - sizeof(cv.b); ++i) {
	*b++ = fill;
	}
	}
	else {
	memset(buffer, fill, n - sizeof(cv.b));
	memcpy((char *)buffer + n - sizeof(cv.b), cv.b, sizeof(cv.b));
	}

Line 1186. The problem is:

• (no warning)

  cpython/Objects/longobject.c

  Line 1173 in b348313

  for (Py_ssize_t i = 0; i < n - (int)sizeof(cv.b); ++i) {

• (warning)

  cpython/Objects/longobject.c

  Line 1186 in b348313

  for (Py_ssize_t i = 0; i < n - sizeof(cv.b); ++i) {

Buildbot link: https://buildbot.python.org/all/#/builders/332/builds/1372

I have a PR ready.

Linked PRs

• gh-115827: Fix compile warning in longobject.c #115828

[sobolevn]

Backports are not needed, this is new in 3.13