[pull] main from python:main - #1397

…tion (GH-156139)

addstr(), addnstr(), insstr() and insnstr() saved the window rendition with
getattrs() and put it back with wattrset(), whose A_COLOR field holds only
pairs 0 to 255, so a window using a larger pair lost it.  Save and restore
the pair with wattr_get() and wattr_set() where they exist.

They are the counterparts of the ACS_* line-drawing codes as complexchar
cells, added to the module by initscr() and newterm() like the ACS_* ones.
Besides the codes that mirror the ACS_* ones, ncurses provides the
double-line and thick-line families, which have no ACS_* counterpart.

…H-156104)

Deleting the attribute crashed, and setting it to an integer which does not
fit in C long reported success with OverflowError set.

In the free-threaded build the setter passed the value to
Py_BEGIN_CRITICAL_SECTION2() before checking it for NULL.

…6105)

PyLong_AsUInt32() stores 0 in the target on error, so the attribute was
clobbered when the assigned value was too large.

)

The integer 0 asks for the default character, but it was rejected when
passed together with a string character.  Choose the drawing function by
what the arguments need: only a complexchar cannot be drawn as a byte
character, and a string character is narrowed when one is needed.

Document the defaults as 0 rather than as the ACS_* codes, which are not
defined before initscr().

* Remove the NEWS entry

The regression is not in any release: wide characters in border() and box()
are new in 3.16.

…sed from: gh-149738 (GH-152818)

…l signatures (#155954)

The setter released the old callback before validating the new value,
so a failed assignment or a deletion removed it.