bpo-43172: readline now passes its tests when built against libedit.
Existing irreconcilable API differences remain in readline.get_begidx
and readline.get_endidx behavior based on libreadline vs libedit use.
A note about that has been documented.
In contrast to macOS, libedit is available as its own include file and
library on Linux systems to prevent file name clashes. So if both
libraries are available on the system, readline is currently chosen by
default; and if only libedit is available, it is not found at all. This
patch adds a way to link against libedit by adding the following
arguments to configure:
--with-readline link against libreadline (the default)
--with-readline=editline link against libeditline
--with-readline=no disable building the readline module
--without-readline (same)
The runtime detection of libedit vs. readline was already done in commit
7105319ada (2019-12-04, serge-sans-paille: "bpo-38634: Allow
non-apple build to cope with libedit (GH-16986)").
Fixes: GH-12076 ("bpo-13501 Build or disable readline with Editline")
Fixes: bpo-13501 ("Make libedit support more generic; port readline / libedit to FreeBSD")
Co-authored-by: Enji Cooper (ngie-eign)
Co-authored-by: Martin Panter (vadmium)
Co-authored-by: Robert Marshall (kellinm)
The readline module now detects if Python is linked to libedit at runtime
on all platforms. Previously, the check was only done on macOS.
If Python is used as a library by a binary linking to libedit, the linker
resolves the rl_initialize symbol required by the readline module against
libedit instead of libreadline, which leads to a segfault.
Take advantage of the existing supporting code to have readline module being
compatible with both situations.
Add a new public PyObject_CallNoArgs() function to the C API: call a
callable Python object without any arguments.
It is the most efficient way to call a callback without any argument.
On x86-64, for example, PyObject_CallFunctionObjArgs(func, NULL)
allocates 960 bytes on the stack per call, whereas
PyObject_CallNoArgs(func) only allocates 624 bytes per call.
It is excluded from stable ABI 3.8.
Replace private _PyObject_CallNoArg() with public
PyObject_CallNoArgs() in C extensions: _asyncio, _datetime,
_elementtree, _pickle, _tkinter and readline.
In _localemodule.c and selectmodule.c, remove dead code that would
cause double decrefs if run.
In addition, replace PyList_SetItem() with PyList_SET_ITEM() in cases
where a new list is populated and there is no possibility of an error.
In addition, check if the list changed size in the loop in array_array_fromlist().
Replace strncpy() with memcpy() in call_readline() to fix the
following warning, the NUL byte is written manually just after:
Modules/readline.c: In function ‘call_readline’:
Modules/readline.c:1303:9: warning: ‘strncpy’ output truncated before
terminating nul copying as many bytes from a string as its length
[-Wstringop-truncation]
strncpy(p, q, n);
^~~~~~~~~~~~~~~~
Modules/readline.c:1279:9: note: length computed here
n = strlen(p);
^~~~~~~~~
Modify locale.localeconv(), time.tzname, os.strerror() and other
functions to ignore the UTF-8 Mode: always use the current locale
encoding.
Changes:
* Add _Py_DecodeLocaleEx() and _Py_EncodeLocaleEx(). On decoding or
encoding error, they return the position of the error and an error
message which are used to raise Unicode errors in
PyUnicode_DecodeLocale() and PyUnicode_EncodeLocale().
* Replace _Py_DecodeCurrentLocale() with _Py_DecodeLocaleEx().
* PyUnicode_DecodeLocale() now uses _Py_DecodeLocaleEx() for all
cases, especially for the strict error handler.
* Add _Py_DecodeUTF8Ex(): return more information on decoding error
and supports the strict error handler.
* Rename _Py_EncodeUTF8_surrogateescape() to _Py_EncodeUTF8Ex().
* Replace _Py_EncodeCurrentLocale() with _Py_EncodeLocaleEx().
* Ignore the UTF-8 mode to encode/decode localeconv(), strerror()
and time zone name.
* Remove PyUnicode_DecodeLocale(), PyUnicode_DecodeLocaleAndSize()
and PyUnicode_EncodeLocale() now ignore the UTF-8 mode: always use
the "current" locale.
* Remove _PyUnicode_DecodeCurrentLocale(),
_PyUnicode_DecodeCurrentLocaleAndSize() and
_PyUnicode_EncodeCurrentLocale().
Add new fuctions ignoring the UTF-8 mode:
* _Py_DecodeCurrentLocale()
* _Py_EncodeCurrentLocale()
* _PyUnicode_DecodeCurrentLocaleAndSize()
* _PyUnicode_EncodeCurrentLocale()
Modify the readline module to use these functions.
Re-enable test_readline.test_nonascii().
Handle PyModule_AddIntConstant() and PyModule_AddStringConstant()
failures. Add also constants before calling setup_readline(), since
setup_readline() registers callbacks which uses a reference to the
module, whereas the module is destroyed if adding constants fails.
Fix Coverity warning:
CID 1414686: Unchecked return value (CHECKED_RETURN)
2. check_return: Calling PyModule_AddStringConstant without checking
return value (as is done elsewhere 45 out of 55 times).
If history-length is set in .inputrc, and the history file is double the
history size (or more), history_get(N) returns NULL, and python
segfaults. Fix that by checking for NULL return value.
It seems that the root cause is incorrect handling of bigger history in
readline, but Python should not segfault even if readline returns
unexpected value.
This issue affects only GNU readline. When using libedit emulation
system history size option does not work.
Replace
PyObject_CallFunction(func, "O", arg)
and
PyObject_CallFunction(func, "O", arg, NULL)
with
_PyObject_CallArg1(func, arg)
Replace
PyObject_CallFunction(func, NULL)
with
_PyObject_CallNoArg(func)
_PyObject_CallNoArg() and _PyObject_CallArg1() are simpler and don't allocate
memory on the C stack.
