LLVM messing up NCurses-based applications

[Quuxplusone]

Bugzilla Link	PR22981
Status	NEW
Importance	P normal
Reported by	Xavier Mendez (me@jmendeth.com)
Reported on	2015-03-22 06:57:58 -0700
Last modified on	2015-12-15 02:15:43 -0800
Version	3.5
Hardware	PC Linux
CC	chandlerc@gmail.com, dblaikie@gmail.com, llvm-bugs@lists.llvm.org, maciej.gajewski0@gmail.com, me@jmendeth.com
Fixed by commit(s)
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When trying to use the Clang Python bindings inside bpython, every time I loaded a TranslationUnit from source, bpython segfaulted.

I've found the problem to be in llvm::sys::Process::FileDescriptorHasColors(int). It uses terminfo to check if the file descriptor has colors, but instead of restoring the cur_term variable to its original value, it sets it to NULL. When control returns to the NCurses app (bpython), it crashes because no current terminal is set.

This is the first time I ever deal with LLVM or NCurses code, so I might be wrong. I did a search to see if this had been reported before, but I didn't find anything.

To reproduce, fire up bpython and enter:

import clang.cindex
clang.cindex.TranslationUnit.from_source("path to some C file")

You need the Clang Python bindings installed, of course.

[Quuxplusone]

I experience the same in C++ application. Just run this code:

#include <ncursesw/ncurses.h>

#include <clang-c/Index.h>

int main(int argc, char** argv)
{
    if (argc < 2) return 1;
    ::initscr();

    CXIndex clang_idx = clang_createIndex(0, 0);
    CXTranslationUnit clang_tu = nullptr;

    clang_tu = clang_parseTranslationUnit(
            clang_idx,
            /*argv[1]*/ nullptr,
            argv, argc, // cmndline
            nullptr, 0, // unsaved data
            clang_defaultEditingTranslationUnitOptions());

    ::endwin(); // this line will crash
        // it doesn't have to be endwin, it could be almost any other
        // curses call
}