readline_libedit.patch

diff -ur Python-3.9.0.orig/Modules/readline.c Python-3.9.0/Modules/readline.c
--- Python-3.9.0.orig/Modules/readline.c	2020-10-23 10:35:53.619118422 +0300
+++ Python-3.9.0/Modules/readline.c	2020-10-23 10:45:12.300876632 +0300
@@ -26,23 +26,20 @@
 #  define RESTORE_LOCALE(sl)
 #endif
 
+#ifdef WITH_EDITLINE
+#  include <editline/readline.h>
+#else
 /* GNU readline definitions */
-#undef HAVE_CONFIG_H /* Else readline/chardefs.h includes strings.h */
-#include <readline/readline.h>
-#include <readline/history.h>
+#  undef HAVE_CONFIG_H /* Else readline/chardefs.h includes strings.h */
+#  include <readline/readline.h>
+#  include <readline/history.h>
+#endif
 
+/* Readline 4.2 deprecated completion_matches() in favour of
++rl_completion_matches() */
 #ifdef HAVE_RL_COMPLETION_MATCHES
 #define completion_matches(x, y) \
     rl_completion_matches((x), ((rl_compentry_func_t *)(y)))
-#else
-#if defined(_RL_FUNCTION_TYPEDEF)
-extern char **completion_matches(char *, rl_compentry_func_t *);
-#else
-
-#if !defined(__APPLE__)
-extern char **completion_matches(char *, CPFunction *);
-#endif
-#endif
 #endif
 
 /*
@@ -50,20 +47,26 @@
  * emulation library of editline/libedit.
  *
  * This emulation library is not 100% API compatible with the "real" readline
- * and cannot be detected at compile-time,
+ * and if WITH_EDITLINE was not specified, cannot be detected at compile-time,
  * hence we use a runtime check to detect if the Python readlinke module is
  * linked to libedit.
- *
- * Currently there is one known API incompatibility:
+ */
+#if !defined(WITH_EDITLINE)
+#  define DETECT_EDITLINE
+static int using_libedit_emulation = 0;
+static const char libedit_version_tag[] = "EditLine wrapper";
+#endif
+
+#if defined(WITH_EDITLINE)
+#  define SUPPORT_EDITLINE
+/* One incompatibility of Editline:
  * - 'get_history' has a 1-based index with GNU readline, and a 0-based
  *   index with older versions of libedit's emulation.
  * - Note that replace_history and remove_history use a 0-based index
  *   with both implementations.
  */
-static int using_libedit_emulation = 0;
-static const char libedit_version_tag[] = "EditLine wrapper";
-
 static int libedit_history_start = 0;
+#endif
 
 #ifdef HAVE_RL_COMPLETION_DISPLAY_MATCHES_HOOK
 static void
@@ -668,25 +671,6 @@
 \n\
 Returns current completer function.");
 
-/* Private function to get current length of history.  XXX It may be
- * possible to replace this with a direct use of history_length instead,
- * but it's not clear whether BSD's libedit keeps history_length up to date.
- * See issue #8065.*/
-
-static int
-_py_get_history_length(void)
-{
-    HISTORY_STATE *hist_st = history_get_history_state();
-    int length = hist_st->length;
-    /* the history docs don't say so, but the address of hist_st changes each
-       time history_get_history_state is called which makes me think it's
-       freshly malloc'd memory...  on the other hand, the address of the last
-       line stays the same as long as history isn't extended, so it appears to
-       be malloc'd but managed by the history package... */
-    free(hist_st);
-    return length;
-}
-
 /* Exported function to get any element of history */
 
 static PyObject *
@@ -697,25 +681,24 @@
 
     if (!PyArg_ParseTuple(args, "i:get_history_item", &idx))
         return NULL;
-    if (using_libedit_emulation) {
-        /* Older versions of libedit's readline emulation
-         * use 0-based indexes, while readline and newer
-         * versions of libedit use 1-based indexes.
-         */
-        int length = _py_get_history_length();
-
-        idx = idx - 1 + libedit_history_start;
-
-        /*
-         * Apple's readline emulation crashes when
-         * the index is out of range, therefore
-         * test for that and fail gracefully.
-         */
-        if (idx < (0 + libedit_history_start)
-                || idx >= (length + libedit_history_start)) {
-            Py_RETURN_NONE;
-        }
+#ifdef SUPPORT_EDITLINE
+    idx = idx - 1 + libedit_history_start;
+
+    /*
+     * Apple's readline emulation crashes when
+     * the index is out of range, therefore
+     * test for that and fail gracefully.
+     */
+    /* KELLIN NOTE:
+     * The initial patch removed the 0 for some unknown to me reason
+     *
+     * if (idx < (0 + libedit_history_start)
+     */
+    if (idx < libedit_history_start
+            || idx >= (history_length + libedit_history_start)) {
+        Py_RETURN_NONE;
     }
+#endif /* SUPPORT_EDITLINE */
     if ((hist_ent = history_get(idx)))
         return decode(hist_ent->line);
     else {
@@ -733,7 +716,7 @@
 static PyObject *
 get_current_history_length(PyObject *self, PyObject *noarg)
 {
-    return PyLong_FromLong((long)_py_get_history_length());
+    return PyLong_FromLong(history_length);
 }
 
 PyDoc_STRVAR(doc_get_current_history_length,
@@ -1083,13 +1066,15 @@
     /* The name must be defined before initialization */
     rl_readline_name = "python";
 
+#ifdef SUPPORT_EDITLINE
     /* the libedit readline emulation resets key bindings etc
-     * when calling rl_initialize.  So call it upfront
+     * when calling rl_initialize.  So call it before making those settings.
      */
+#  ifdef DETECT_EDITLINE
     if (using_libedit_emulation)
+#  endif 
         rl_initialize();
-
-    /* Detect if libedit's readline emulation uses 0-based
+    /* Detect if the backend library uses 0-based
      * indexing or 1-based indexing.
      */
     add_history("1");
@@ -1099,6 +1084,7 @@
         libedit_history_start = 1;
     }
     clear_history();
+#endif /* SUPPORT_EDITLINE */
 
     using_history();
 
@@ -1127,7 +1113,9 @@
     mod_state->begidx = PyLong_FromLong(0L);
     mod_state->endidx = PyLong_FromLong(0L);
 
+#ifdef DETECT_EDITLINE
     if (!using_libedit_emulation)
+#endif
     {
         if (!isatty(STDOUT_FILENO)) {
             /* Issue #19884: stdout is not a terminal. Disable meta modifier
@@ -1146,11 +1134,20 @@
      *
      * XXX: A bug in the readline-2.2 library causes a memory leak
      * inside this function.  Nothing we can do about it.
+     *
+     * For Editline, just invoke the user configuration; initialization was
+     * already done above.
      */
+#ifdef DETECT_EDITLINE
     if (using_libedit_emulation)
         rl_read_init_file(NULL);
     else
         rl_initialize();
+#elif defined(WITH_EDITLINE)
+        rl_read_init_file(NULL);
+#else
+        rl_initialize();
+#endif
 
     RESTORE_LOCALE(saved_locale)
     return 0;
@@ -1276,14 +1273,13 @@
     n = strlen(p);
     if (should_auto_add_history && n > 0) {
         const char *line;
-        int length = _py_get_history_length();
-        if (length > 0) {
+        if (history_length > 0) {
             HIST_ENTRY *hist_ent;
-            if (using_libedit_emulation) {
-                /* handle older 0-based or newer 1-based indexing */
-                hist_ent = history_get(length + libedit_history_start - 1);
-            } else
-                hist_ent = history_get(length);
+#ifdef SUPPORT_EDITLINE
+            hist_ent = history_get(history_length + libedit_history_start - 1);
+#else
+            hist_ent = history_get(history_length);
+#endif
             line = hist_ent ? hist_ent->line : "";
         } else
             line = "";
@@ -1308,10 +1304,15 @@
 /* Initialize the module */
 
 PyDoc_STRVAR(doc_module,
+#ifndef WITH_EDITLINE
 "Importing this module enables command line editing using GNU readline.");
-
+#endif
+#ifdef DETECT_EDITLINE
 PyDoc_STRVAR(doc_module_le,
+#endif
+#ifdef SUPPORT_EDITLINE
 "Importing this module enables command line editing using libedit readline.");
+#endif
 
 static struct PyModuleDef readlinemodule = {
     PyModuleDef_HEAD_INIT,
@@ -1332,13 +1333,14 @@
     PyObject *m;
     readlinestate *mod_state;
 
+#ifdef DETECT_EDITLINE
     if (strncmp(rl_library_version, libedit_version_tag, strlen(libedit_version_tag)) == 0) {
         using_libedit_emulation = 1;
     }
 
     if (using_libedit_emulation)
         readlinemodule.m_doc = doc_module_le;
-
+#endif /* DETECT_EDITLINE */
 
     m = PyModule_Create(&readlinemodule);
 
diff -ur Python-3.9.0.orig/configure Python-3.9.0/configure
--- Python-3.9.0.orig/configure	2020-10-23 10:35:53.452460203 +0300
+++ Python-3.9.0/configure	2020-10-23 10:55:42.742362204 +0300
@@ -846,6 +846,7 @@
 with_libc
 enable_big_digits
 with_platlibdir
+with_readline
 with_computed_gotos
 with_ensurepip
 with_openssl
@@ -1572,6 +1573,8 @@
                           system-dependent)
   --with-platlibdir=DIRNAME
                           Python library directory name (default is "lib")
+  --with(out)-readline[=editline]
+                          use Editline for backend or disable readline module
   --with-computed-gotos   enable computed gotos in evaluation loop (enabled by
                           default on supported compilers)
   --with-ensurepip[=install|upgrade|no]
@@ -15471,24 +15474,49 @@
 
 fi
 
+
+# Check whether --with-readline was given.
+if test "${with_readline+set}" = set; then :
+  withval=$with_readline;
+else
+  with_readline=yes
+fi
+
+
 # check where readline lives
+py_cv_lib_readline=no
 # save the value of LIBS so we don't actually link Python with readline
 LIBS_no_readline=$LIBS
 
-# On some systems we need to link readline to a termcap compatible
-# library.  NOTE: Keep the precedence of listed libraries synchronised
-# with setup.py.
-py_cv_lib_readline=no
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking how to link readline libs" >&5
+if test "$with_readline" != no; then
+  case "$with_readline" in
+  editline|edit)
+    LIBREADLINE=edit
+
+$as_echo "#define WITH_EDITLINE 1" >>confdefs.h
+
+    ;;
+  yes|readline)
+    LIBREADLINE=readline
+    ;;
+  *)
+    as_fn_error $? "proper usage is --with(out)-readline[=editline]" "$LINENO" 5
+    ;;
+  esac
+
+  # On some systems we need to link readline to a termcap compatible
+  # library.  NOTE: Keep the precedence of listed libraries synchronised
+  # with setup.py.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking how to link readline libs" >&5
 $as_echo_n "checking how to link readline libs... " >&6; }
-for py_libtermcap in "" tinfo ncursesw ncurses curses termcap; do
-  if test -z "$py_libtermcap"; then
-    READLINE_LIBS="-lreadline"
-  else
-    READLINE_LIBS="-lreadline -l$py_libtermcap"
-  fi
-  LIBS="$READLINE_LIBS $LIBS_no_readline"
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+  for py_libtermcap in "" tinfo ncursesw ncurses curses termcap; do
+    if test -z "$py_libtermcap"; then
+      READLINE_LIBS="-l$LIBREADLINE"
+    else
+      READLINE_LIBS="-l$LIBREADLINE -l$py_libtermcap"
+    fi
+    LIBS="$READLINE_LIBS $LIBS_no_readline"
+    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
 /* Override any GCC internal prototype to avoid an error.
@@ -15511,73 +15539,67 @@
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
-  if test $py_cv_lib_readline = yes; then
-    break
-  fi
-done
-# Uncomment this line if you want to use READINE_LIBS in Makefile or scripts
-#AC_SUBST([READLINE_LIBS])
-if test $py_cv_lib_readline = no; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: none" >&5
+    if test $py_cv_lib_readline = yes; then
+      break
+    fi
+  done
+
+  # Uncomment this line if you want to use READLINE_LIBS in Makefile or scripts
+  #AC_SUBST([READLINE_LIBS])
+  if test $py_cv_lib_readline = no; then
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: none" >&5
 $as_echo "none" >&6; }
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $READLINE_LIBS" >&5
+  else
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: $READLINE_LIBS" >&5
 $as_echo "$READLINE_LIBS" >&6; }
 
 $as_echo "#define HAVE_LIBREADLINE 1" >>confdefs.h
 
+  fi
 fi
 
-# check for readline 2.2
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#include <readline/readline.h>
-_ACEOF
-if ac_fn_c_try_cpp "$LINENO"; then :
-  have_readline=yes
-else
-  have_readline=no
-
-fi
-rm -f conftest.err conftest.i conftest.$ac_ext
-if test $have_readline = yes
-then
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#include <readline/readline.h>
+if test "$py_cv_lib_readline" = yes; then
+  # check for readline 2.2
+  ac_fn_c_check_decl "$LINENO" "rl_completion_append_character" "ac_cv_have_decl_rl_completion_append_character" "
+#include <stdio.h> /* Must be first for Gnu Readline */
+#ifdef WITH_EDITLINE
+# include <editline/readline.h>
+#else
+# include <readline/readline.h>
+#endif
 
-_ACEOF
-if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
-  $EGREP "extern int rl_completion_append_character;" >/dev/null 2>&1; then :
+"
+if test "x$ac_cv_have_decl_rl_completion_append_character" = xyes; then :
 
-$as_echo "#define HAVE_RL_COMPLETION_APPEND_CHARACTER 1" >>confdefs.h
+  $as_echo "#define HAVE_RL_COMPLETION_APPEND_CHARACTER 1" >>confdefs.h
 
 fi
-rm -f conftest*
 
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#include <readline/readline.h>
+  ac_fn_c_check_decl "$LINENO" "rl_completion_suppress_append" "ac_cv_have_decl_rl_completion_suppress_append" "
+#include <stdio.h> /* Must be first for Gnu Readline */
+#ifdef WITH_EDITLINE
+# include <editline/readline.h>
+#else
+# include <readline/readline.h>
+#endif
 
-_ACEOF
-if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
-  $EGREP "extern int rl_completion_suppress_append;" >/dev/null 2>&1; then :
+"
+if test "x$ac_cv_have_decl_rl_completion_suppress_append" = xyes; then :
 
 $as_echo "#define HAVE_RL_COMPLETION_SUPPRESS_APPEND 1" >>confdefs.h
 
 fi
-rm -f conftest*
 
-fi
 
-# check for readline 4.0
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_pre_input_hook in -lreadline" >&5
-$as_echo_n "checking for rl_pre_input_hook in -lreadline... " >&6; }
-if ${ac_cv_lib_readline_rl_pre_input_hook+:} false; then :
+  # check for readline 4.0
+  as_ac_Lib=`$as_echo "ac_cv_lib_$LIBREADLINE''_rl_pre_input_hook" | $as_tr_sh`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_pre_input_hook in -l$LIBREADLINE" >&5
+$as_echo_n "checking for rl_pre_input_hook in -l$LIBREADLINE... " >&6; }
+if eval \${$as_ac_Lib+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lreadline $READLINE_LIBS $LIBS"
+LIBS="-l$LIBREADLINE $READLINE_LIBS $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -15597,31 +15619,34 @@
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_readline_rl_pre_input_hook=yes
+  eval "$as_ac_Lib=yes"
 else
-  ac_cv_lib_readline_rl_pre_input_hook=no
+  eval "$as_ac_Lib=no"
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_readline_rl_pre_input_hook" >&5
-$as_echo "$ac_cv_lib_readline_rl_pre_input_hook" >&6; }
-if test "x$ac_cv_lib_readline_rl_pre_input_hook" = xyes; then :
+eval ac_res=\$$as_ac_Lib
+          { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+
+if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
 
 $as_echo "#define HAVE_RL_PRE_INPUT_HOOK 1" >>confdefs.h
 
 fi
 
 
-# also in 4.0
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_completion_display_matches_hook in -lreadline" >&5
-$as_echo_n "checking for rl_completion_display_matches_hook in -lreadline... " >&6; }
-if ${ac_cv_lib_readline_rl_completion_display_matches_hook+:} false; then :
+  # also in 4.0
+  as_ac_Lib=`$as_echo "ac_cv_lib_$LIBREADLINE''_rl_completion_display_matches_hook" | $as_tr_sh`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_completion_display_matches_hook in -l$LIBREADLINE" >&5
+$as_echo_n "checking for rl_completion_display_matches_hook in -l$LIBREADLINE... " >&6; }
+if eval \${$as_ac_Lib+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lreadline $READLINE_LIBS $LIBS"
+LIBS="-l$LIBREADLINE $READLINE_LIBS $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -15641,31 +15666,34 @@
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_readline_rl_completion_display_matches_hook=yes
+  eval "$as_ac_Lib=yes"
 else
-  ac_cv_lib_readline_rl_completion_display_matches_hook=no
+  eval "$as_ac_Lib=no"
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_readline_rl_completion_display_matches_hook" >&5
-$as_echo "$ac_cv_lib_readline_rl_completion_display_matches_hook" >&6; }
-if test "x$ac_cv_lib_readline_rl_completion_display_matches_hook" = xyes; then :
+eval ac_res=\$$as_ac_Lib
+          { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+
+if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
 
 $as_echo "#define HAVE_RL_COMPLETION_DISPLAY_MATCHES_HOOK 1" >>confdefs.h
 
 fi
 
 
-# also in 4.0, but not in editline
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_resize_terminal in -lreadline" >&5
-$as_echo_n "checking for rl_resize_terminal in -lreadline... " >&6; }
-if ${ac_cv_lib_readline_rl_resize_terminal+:} false; then :
+  # also in 4.0, but not in editline
+  as_ac_Lib=`$as_echo "ac_cv_lib_$LIBREADLINE''_rl_resize_terminal" | $as_tr_sh`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_resize_terminal in -l$LIBREADLINE" >&5
+$as_echo_n "checking for rl_resize_terminal in -l$LIBREADLINE... " >&6; }
+if eval \${$as_ac_Lib+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lreadline $READLINE_LIBS $LIBS"
+LIBS="-l$LIBREADLINE $READLINE_LIBS $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -15685,31 +15713,33 @@
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_readline_rl_resize_terminal=yes
+  eval "$as_ac_Lib=yes"
 else
-  ac_cv_lib_readline_rl_resize_terminal=no
+  eval "$as_ac_Lib=no"
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_readline_rl_resize_terminal" >&5
-$as_echo "$ac_cv_lib_readline_rl_resize_terminal" >&6; }
-if test "x$ac_cv_lib_readline_rl_resize_terminal" = xyes; then :
+eval ac_res=\$$as_ac_Lib
+          { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
 
 $as_echo "#define HAVE_RL_RESIZE_TERMINAL 1" >>confdefs.h
 
 fi
 
 
-# check for readline 4.2
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_completion_matches in -lreadline" >&5
-$as_echo_n "checking for rl_completion_matches in -lreadline... " >&6; }
-if ${ac_cv_lib_readline_rl_completion_matches+:} false; then :
+  # check for readline 4.2
+  as_ac_Lib=`$as_echo "ac_cv_lib_$LIBREADLINE''_rl_completion_matches" | $as_tr_sh`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_completion_matches in -l$LIBREADLINE" >&5
+$as_echo_n "checking for rl_completion_matches in -l$LIBREADLINE... " >&6; }
+if eval \${$as_ac_Lib+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lreadline $READLINE_LIBS $LIBS"
+LIBS="-l$LIBREADLINE $READLINE_LIBS $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -15729,59 +15759,49 @@
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_readline_rl_completion_matches=yes
+  eval "$as_ac_Lib=yes"
 else
-  ac_cv_lib_readline_rl_completion_matches=no
+  eval "$as_ac_Lib=no"
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_readline_rl_completion_matches" >&5
-$as_echo "$ac_cv_lib_readline_rl_completion_matches" >&6; }
-if test "x$ac_cv_lib_readline_rl_completion_matches" = xyes; then :
+eval ac_res=\$$as_ac_Lib
+          { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+
+if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
 
 $as_echo "#define HAVE_RL_COMPLETION_MATCHES 1" >>confdefs.h
 
 fi
 
 
-# also in readline 4.2
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#include <readline/readline.h>
-_ACEOF
-if ac_fn_c_try_cpp "$LINENO"; then :
-  have_readline=yes
-else
-  have_readline=no
-
-fi
-rm -f conftest.err conftest.i conftest.$ac_ext
-if test $have_readline = yes
-then
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#include <readline/readline.h>
+  # also in readline 4.2
+  ac_fn_c_check_decl "$LINENO" "rl_catch_signals" "ac_cv_have_decl_rl_catch_signals" "
+#include <stdio.h> /* Must be first for Gnu Readline */
+#ifdef WITH_EDITLINE
+# include <editline/readline.h>
+#else
+# include <readline/readline.h>
+#endif
 
-_ACEOF
-if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
-  $EGREP "extern int rl_catch_signals;" >/dev/null 2>&1; then :
+"
+if test "x$ac_cv_have_decl_rl_catch_signals" = xyes; then :
 
 $as_echo "#define HAVE_RL_CATCH_SIGNAL 1" >>confdefs.h
 
 fi
-rm -f conftest*
-
-fi
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for append_history in -lreadline" >&5
-$as_echo_n "checking for append_history in -lreadline... " >&6; }
-if ${ac_cv_lib_readline_append_history+:} false; then :
+  as_ac_Lib=`$as_echo "ac_cv_lib_$LIBREADLINE''_append_history" | $as_tr_sh`
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for append_history in -l$LIBREADLINE" >&5
+$as_echo_n "checking for append_history in -l$LIBREADLINE... " >&6; }
+if eval \${$as_ac_Lib+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
-LIBS="-lreadline $READLINE_LIBS $LIBS"
+LIBS="-l$LIBREADLINE $READLINE_LIBS $LIBS"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -15801,22 +15821,24 @@
 }
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_lib_readline_append_history=yes
+  eval "$as_ac_Lib=yes"
 else
-  ac_cv_lib_readline_append_history=no
+  eval "$as_ac_Lib=no"
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 LIBS=$ac_check_lib_save_LIBS
 fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_readline_append_history" >&5
-$as_echo "$ac_cv_lib_readline_append_history" >&6; }
-if test "x$ac_cv_lib_readline_append_history" = xyes; then :
+eval ac_res=\$$as_ac_Lib
+          { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
 
 $as_echo "#define HAVE_RL_APPEND_HISTORY 1" >>confdefs.h
 
 fi
 
+fi
 
 # End of readline checks: restore LIBS
 LIBS=$LIBS_no_readline
diff -ur Python-3.9.0.orig/configure.ac Python-3.9.0/configure.ac
--- Python-3.9.0.orig/configure.ac	2020-10-23 10:35:53.392463243 +0300
+++ Python-3.9.0/configure.ac	2020-10-23 11:01:15.675567214 +0300
@@ -4856,93 +4856,125 @@
   [Define this if you have flockfile(), getc_unlocked(), and funlockfile()])
 fi
 
+AC_ARG_WITH([readline],
+  [AS_HELP_STRING([--with(out)-readline@<:@=editline@:>@],
+    [use Editline for backend or disable readline module])],
+    [],
+    [with_readline=yes])
+
 # check where readline lives
+py_cv_lib_readline=no
 # save the value of LIBS so we don't actually link Python with readline
 LIBS_no_readline=$LIBS
 
-# On some systems we need to link readline to a termcap compatible
-# library.  NOTE: Keep the precedence of listed libraries synchronised
-# with setup.py.
-py_cv_lib_readline=no
-AC_MSG_CHECKING([how to link readline libs])
-for py_libtermcap in "" tinfo ncursesw ncurses curses termcap; do
-  if test -z "$py_libtermcap"; then
-    READLINE_LIBS="-lreadline"
+if test "$with_readline" != no; then
+  case "$with_readline" in
+  editline|edit)
+    LIBREADLINE=edit
+    AC_DEFINE(WITH_EDITLINE, 1,
+      [Define to build the readline module against Editline.])
+    ;;
+  yes|readline)
+    LIBREADLINE=readline
+    ;;
+  *)
+    AC_MSG_ERROR([proper usage is --with(out)-readline@<:@=editline@:>@])
+    ;;
+  esac
+
+  # On some systems we need to link readline to a termcap compatible
+  # library.  NOTE: Keep the precedence of listed libraries synchronised
+  # with setup.py.
+  AC_MSG_CHECKING([how to link readline libs])
+  for py_libtermcap in "" tinfo ncursesw ncurses curses termcap; do
+    if test -z "$py_libtermcap"; then
+      READLINE_LIBS="-l$LIBREADLINE"
+    else
+      READLINE_LIBS="-l$LIBREADLINE -l$py_libtermcap"
+    fi
+    LIBS="$READLINE_LIBS $LIBS_no_readline"
+    AC_LINK_IFELSE(
+      [AC_LANG_CALL([],[readline])],
+      [py_cv_lib_readline=yes])
+    if test $py_cv_lib_readline = yes; then
+      break
+    fi
+  done
+
+  # Uncomment this line if you want to use READLINE_LIBS in Makefile or scripts
+  #AC_SUBST([READLINE_LIBS])
+  if test $py_cv_lib_readline = no; then
+    AC_MSG_RESULT([none])
   else
-    READLINE_LIBS="-lreadline -l$py_libtermcap"
-  fi
-  LIBS="$READLINE_LIBS $LIBS_no_readline"
-  AC_LINK_IFELSE(
-    [AC_LANG_CALL([],[readline])],
-    [py_cv_lib_readline=yes])
-  if test $py_cv_lib_readline = yes; then
-    break
+    AC_MSG_RESULT([$READLINE_LIBS])
+    AC_DEFINE(HAVE_LIBREADLINE, 1,
+      [Define to build the readline module.])
   fi
-done
-# Uncomment this line if you want to use READINE_LIBS in Makefile or scripts
-#AC_SUBST([READLINE_LIBS])
-if test $py_cv_lib_readline = no; then
-  AC_MSG_RESULT([none])
-else
-  AC_MSG_RESULT([$READLINE_LIBS])
-  AC_DEFINE(HAVE_LIBREADLINE, 1,
-    [Define if you have the readline library (-lreadline).])
 fi
 
-# check for readline 2.2
-AC_PREPROC_IFELSE([AC_LANG_SOURCE([[#include <readline/readline.h>]])],
-  [have_readline=yes],
-  [have_readline=no]
-)
-if test $have_readline = yes
-then
-  AC_EGREP_HEADER([extern int rl_completion_append_character;],
-  [readline/readline.h],
-  AC_DEFINE(HAVE_RL_COMPLETION_APPEND_CHARACTER, 1,
-  [Define if you have readline 2.2]), )
-  AC_EGREP_HEADER([extern int rl_completion_suppress_append;],
-  [readline/readline.h],
-  AC_DEFINE(HAVE_RL_COMPLETION_SUPPRESS_APPEND, 1,
-  [Define if you have rl_completion_suppress_append]), )
+if test "$py_cv_lib_readline" = yes; then
+  # check for readline 2.2
+  AC_CHECK_DECL(rl_completion_append_character,
+    AC_DEFINE(HAVE_RL_COMPLETION_APPEND_CHARACTER, 1,
+      [Define if you have readline 2.2]),,
+    [
+#include <stdio.h> /* Must be first for Gnu Readline */
+#ifdef WITH_EDITLINE
+# include <editline/readline.h>
+#else
+# include <readline/readline.h>
+#endif
+    ])
+  AC_CHECK_DECL(rl_completion_suppress_append,
+    AC_DEFINE(HAVE_RL_COMPLETION_SUPPRESS_APPEND, 1,
+      [Define if you have rl_completion_suppress_append]),,
+    [
+#include <stdio.h> /* Must be first for Gnu Readline */
+#ifdef WITH_EDITLINE
+# include <editline/readline.h>
+#else
+# include <readline/readline.h>
+#endif
+    ])
+
+  # check for readline 4.0
+  AC_CHECK_LIB($LIBREADLINE, rl_pre_input_hook,
+    AC_DEFINE(HAVE_RL_PRE_INPUT_HOOK, 1,
+      [Define if you have readline 4.0]),,$READLINE_LIBS)
+
+  # also in 4.0
+  AC_CHECK_LIB($LIBREADLINE, rl_completion_display_matches_hook,
+    AC_DEFINE(HAVE_RL_COMPLETION_DISPLAY_MATCHES_HOOK, 1,
+      [Define if you have readline 4.0]),,$READLINE_LIBS)
+
+  # also in 4.0, but not in editline
+  AC_CHECK_LIB($LIBREADLINE, rl_resize_terminal,
+    AC_DEFINE(HAVE_RL_RESIZE_TERMINAL, 1,
+      [Define if you have readline 4.0]),,$READLINE_LIBS)
+
+  # check for readline 4.2
+  AC_CHECK_LIB($LIBREADLINE, rl_completion_matches,
+    AC_DEFINE(HAVE_RL_COMPLETION_MATCHES, 1,
+      [Define if you have readline 4.2]),,$READLINE_LIBS)
+
+  # also in readline 4.2
+  AC_CHECK_DECL(rl_catch_signals,
+    AC_DEFINE(HAVE_RL_CATCH_SIGNAL, 1,
+      [Define if you can turn off readline's signal handling.]),,
+    [
+#include <stdio.h> /* Must be first for Gnu Readline */
+#ifdef WITH_EDITLINE
+# include <editline/readline.h>
+#else
+# include <readline/readline.h>
+#endif
+    ])
+
+  AC_CHECK_LIB($LIBREADLINE, append_history,
+    AC_DEFINE(HAVE_RL_APPEND_HISTORY, 1,
+      [Define if readline supports append_history]),,$READLINE_LIBS)
 fi
 
-# check for readline 4.0
-AC_CHECK_LIB(readline, rl_pre_input_hook,
-	AC_DEFINE(HAVE_RL_PRE_INPUT_HOOK, 1,
-        [Define if you have readline 4.0]), ,$READLINE_LIBS)
-
-# also in 4.0
-AC_CHECK_LIB(readline, rl_completion_display_matches_hook,
-	AC_DEFINE(HAVE_RL_COMPLETION_DISPLAY_MATCHES_HOOK, 1,
-        [Define if you have readline 4.0]), ,$READLINE_LIBS)
-
-# also in 4.0, but not in editline
-AC_CHECK_LIB(readline, rl_resize_terminal,
-	AC_DEFINE(HAVE_RL_RESIZE_TERMINAL, 1,
-        [Define if you have readline 4.0]), ,$READLINE_LIBS)
-
-# check for readline 4.2
-AC_CHECK_LIB(readline, rl_completion_matches,
-	AC_DEFINE(HAVE_RL_COMPLETION_MATCHES, 1,
-        [Define if you have readline 4.2]), ,$READLINE_LIBS)
-
-# also in readline 4.2
-AC_PREPROC_IFELSE([AC_LANG_SOURCE([[#include <readline/readline.h>]])],
-  [have_readline=yes],
-  [have_readline=no]
-)
-if test $have_readline = yes
-then
-  AC_EGREP_HEADER([extern int rl_catch_signals;],
-  [readline/readline.h],
-  AC_DEFINE(HAVE_RL_CATCH_SIGNAL, 1,
-  [Define if you can turn off readline's signal handling.]), )
-fi
-
-AC_CHECK_LIB(readline, append_history,
-	AC_DEFINE(HAVE_RL_APPEND_HISTORY, 1,
-        [Define if readline supports append_history]), ,$READLINE_LIBS)
-
 # End of readline checks: restore LIBS
 LIBS=$LIBS_no_readline
 
diff -ur Python-3.9.0.orig/pyconfig.h.in Python-3.9.0/pyconfig.h.in
--- Python-3.9.0.orig/pyconfig.h.in	2020-10-23 10:35:53.645783737 +0300
+++ Python-3.9.0/pyconfig.h.in	2020-10-23 10:36:41.496691638 +0300
@@ -598,7 +598,7 @@
 /* Define to 1 if you have the <libintl.h> header file. */
 #undef HAVE_LIBINTL_H
 
-/* Define if you have the readline library (-lreadline). */
+/* Define to build the readline module. */
 #undef HAVE_LIBREADLINE
 
 /* Define to 1 if you have the `resolv' library (-lresolv). */
@@ -1536,6 +1536,9 @@
    Dyld is necessary to support frameworks. */
 #undef WITH_DYLD
 
+/* Define to build the readline module against Editline. */
+#undef WITH_EDITLINE
+
 /* Define to 1 if libintl is needed for locale functions. */
 #undef WITH_LIBINTL
 
diff -ur Python-3.9.0.orig/setup.py Python-3.9.0/setup.py
--- Python-3.9.0.orig/setup.py	2020-10-23 10:35:53.392463243 +0300
+++ Python-3.9.0/setup.py	2020-10-23 11:01:58.906729487 +0300
@@ -978,7 +978,6 @@
 
     def detect_readline_curses(self):
         # readline
-        do_readline = self.compiler.find_library_file(self.lib_dirs, 'readline')
         readline_termcap_library = ""
         curses_library = ""
         # Cannot use os.popen here in py3k.
@@ -986,7 +985,13 @@
         if not os.path.exists(self.build_temp):
             os.makedirs(self.build_temp)
         # Determine if readline is already linked against curses or tinfo.
-        if do_readline:
+        if sysconfig.get_config_var('HAVE_LIBREADLINE'):
+            if sysconfig.get_config_var('WITH_EDITLINE'):
+                readline_lib = 'edit'
+            else:
+                readline_lib = 'readline'
+            do_readline = self.compiler.find_library_file(self.lib_dirs,
+                readline_lib)
             if CROSS_COMPILING:
                 ret = run_command("%s -d %s | grep '(NEEDED)' > %s"
                                 % (sysconfig.get_config_var('READELF'),
@@ -1009,6 +1014,8 @@
                             break
             if os.path.exists(tmpfile):
                 os.unlink(tmpfile)
+        else:
+            do_readline = False
         # 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:
@@ -1048,7 +1055,7 @@
             else:
                 readline_extra_link_args = ()
 
-            readline_libs = ['readline']
+            readline_libs = [readline_lib]
             if readline_termcap_library:
                 pass # Issue 7384: Already linked against curses or tinfo.
             elif curses_library: