Issue #7384: If the system readline library is linked against ncurses,

the curses module must be linked against ncurses as well. Otherwise it
is not safe to load both the readline and curses modules in an application.

Thanks Thomas Dickey for answering questions about ncurses/ncursesw
and readline!

1 files changed, 37 insertions, 19 deletions

diff --git a/setup.py b/setup.py
index 7294a16..cb65f46 100644
--- a/setup.py
+++ b/setup.py
@@ -588,6 +588,32 @@ class PyBuildExt(build_ext):
 
         # readline
         do_readline = self.compiler.find_library_file(lib_dirs, 'readline')
+        readline_termcap_library = ""
+        curses_library = ""
+        # Determine if readline is already linked against curses or tinfo.
+        if do_readline and platform != 'darwin': # OS X does not have ldd.
+            fp = os.popen("ldd %s" % do_readline)
+            for ln in fp:
+                if 'curses' in ln:
+                    readline_termcap_library = re.sub(
+                        r'.*lib(n?cursesw?)\.so.*', r'\1', ln
+                    ).rstrip()
+                    break
+                if 'tinfo' in ln: # termcap interface split out from ncurses
+                    readline_termcap_library = 'tinfo'
+                    break
+            fp.close()
+        # Issue 7384: If readline is already linked against curses,
+        # use the same library for the readline and curses modules.
+        if 'curses' in readline_termcap_library:
+            curses_library = readline_termcap_library
+        elif self.compiler_obj.find_library_file(lib_dirs, 'ncursesw'):
+            curses_library = 'ncursesw'
+        elif self.compiler_obj.find_library_file(lib_dirs, 'ncurses'):
+            curses_library = 'ncurses'
+        elif self.compiler_obj.find_library_file(lib_dirs, 'curses'):
+            curses_library = 'curses'
+
         if platform == 'darwin':
             os_release = int(os.uname()[2].split('.')[0])
             dep_target = sysconfig.get_config_var('MACOSX_DEPLOYMENT_TARGET')
@@ -611,14 +637,10 @@ class PyBuildExt(build_ext):
                 readline_extra_link_args = ()
 
             readline_libs = ['readline']
-            if self.compiler.find_library_file(lib_dirs,
-                                                   'ncursesw'):
-                readline_libs.append('ncursesw')
-            elif self.compiler.find_library_file(lib_dirs,
-                                                     'ncurses'):
-                readline_libs.append('ncurses')
-            elif self.compiler.find_library_file(lib_dirs, 'curses'):
-                readline_libs.append('curses')
+            if readline_termcap_library:
+                pass # Issue 7384: Already linked against curses or tinfo.
+            elif curses_library:
+                readline_libs.append(curses_library)
             elif self.compiler.find_library_file(lib_dirs +
                                                      ['/usr/lib/termcap'],
                                                      'termcap'):
@@ -1187,19 +1209,15 @@ class PyBuildExt(build_ext):
         # Curses support, requiring the System V version of curses, often
         # provided by the ncurses library.
         panel_library = 'panel'
-        if (self.compiler.find_library_file(lib_dirs, 'ncursesw')):
-            curses_libs = ['ncursesw']
-            # Bug 1464056: If _curses.so links with ncursesw,
-            # _curses_panel.so must link with panelw.
-            panel_library = 'panelw'
-            exts.append( Extension('_curses', ['_cursesmodule.c'],
-                                   libraries = curses_libs) )
-        elif (self.compiler.find_library_file(lib_dirs, 'ncurses')):
-            curses_libs = ['ncurses']
+        if curses_library.startswith('ncurses'):
+            if curses_library == 'ncursesw':
+                # Bug 1464056: If _curses.so links with ncursesw,
+                # _curses_panel.so must link with panelw.
+                panel_library = 'panelw'
+            curses_libs = [curses_library]
             exts.append( Extension('_curses', ['_cursesmodule.c'],
                                    libraries = curses_libs) )
-        elif (self.compiler.find_library_file(lib_dirs, 'curses')
-              and platform != 'darwin'):
+        elif curses_library == 'curses' and platform != 'darwin':
                 # OSX has an old Berkeley curses, not good enough for
                 # the _curses module.
             if (self.compiler.find_library_file(lib_dirs, 'terminfo')):