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!

Lib/test/test_curses.py

@@ -23,11 +23,6 @@ requires('curses')
 curses = import_module('curses')
 curses.panel = import_module('curses.panel')
 
-# skip all these tests on FreeBSD: test_curses currently hangs the
-# FreeBSD buildbots, preventing other tests from running.  See issue
-# #7384.
-if 'freebsd' in sys.platform:
-    raise unittest.SkipTest('The curses module is broken on FreeBSD.  See http://bugs.python.org/issue7384.')
 
 # XXX: if newterm was supported we could use it instead of initscr and not exit
 term = os.environ.get('TERM')

setup.py

@@ -14,6 +14,7 @@ from distutils.core import Extension, setup
 from distutils.command.build_ext import build_ext
 from distutils.command.install import install
 from distutils.command.install_lib import install_lib
+from distutils.spawn import find_executable
 
 # Were we compiled --with-pydebug or with #define Py_DEBUG?
 COMPILED_WITH_PYDEBUG = hasattr(sys, 'gettotalrefcount')
@@ -525,6 +526,38 @@ class PyBuildExt(build_ext):
 
         # readline
         do_readline = self.compiler_obj.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 find_executable('ldd'):
+            # Cannot use os.popen here in py3k.
+            tmpfile = os.path.join(self.build_temp, 'readline_termcap_lib')
+            if not os.path.exists(self.build_temp):
+                os.makedirs(self.build_temp)
+            os.system("ldd %s > %s" % (do_readline, tmpfile))
+            fp = open(tmpfile)
+            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()
+            os.unlink(tmpfile)
+        # 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')
@@ -548,14 +581,10 @@ class PyBuildExt(build_ext):
                 readline_extra_link_args = ()
 
             readline_libs = ['readline']
-            if self.compiler_obj.find_library_file(lib_dirs,
-                                                   'ncursesw'):
-                readline_libs.append('ncursesw')
-            elif self.compiler_obj.find_library_file(lib_dirs,
-                                                     'ncurses'):
-                readline_libs.append('ncurses')
-            elif self.compiler_obj.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_obj.find_library_file(lib_dirs +
                                                      ['/usr/lib/termcap'],
                                                      'termcap'):
@@ -1070,19 +1099,15 @@ 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_obj.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'
+        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_obj.find_library_file(lib_dirs, 'ncurses')):
-            curses_libs = ['ncurses']
-            exts.append( Extension('_curses', ['_cursesmodule.c'],
-                                   libraries = curses_libs) )
-        elif (self.compiler_obj.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_obj.find_library_file(lib_dirs, 'terminfo')):