Implement readline.set_auto_history()

As in cPython 3.5, from https://bugs.python.org/issue26870

pyrepl/historical_reader.py

@@ -207,6 +207,7 @@ def __init__(self, console):
         self.transient_history = {}
         self.next_history = None
         self.isearch_direction = ISEARCH_DIRECTION_NONE
+        self.should_auto_add_history = True
         for c in [next_history, previous_history, restore_history,
                   first_history, last_history, yank_arg,
                   forward_history_isearch, reverse_history_isearch,
@@ -291,12 +292,13 @@ def isearch_next(self):
 
     def finish(self):
         super(HistoricalReader, self).finish()
-        ret = self.get_unicode()
-        for i, t in self.transient_history.items():
-            if i < len(self.history) and i != self.historyi:
-                self.history[i] = t
-        if ret:
-            self.history.append(ret)
+        if self.should_auto_add_history:
+            ret = self.get_unicode()
+            for i, t in self.transient_history.items():
+                if i < len(self.history) and i != self.historyi:
+                    self.history[i] = t
+            if ret:
+                self.history.append(ret)
 
 def test():
     from pyrepl.unix_console import UnixConsole

pyrepl/readline.py

@@ -62,6 +62,7 @@
     'redisplay',
     'remove_history_item',
     'replace_history_item',
+    'set_auto_history',
     'set_completer',
     'set_completer_delims',
     'set_history_length',
@@ -252,6 +253,9 @@ def multiline_input(self, more_lines, ps1, ps2, returns_unicode=False):
     def parse_and_bind(self, string):
         pass  # XXX we don't support parsing GNU-readline-style init files
 
+    def set_auto_history(self, enabled):
+        self.get_reader().should_auto_add_history = enabled
+
     def set_completer(self, function=None):
         self.config.readline_completer = function
 
@@ -400,6 +404,7 @@ def insert_text(self, text):
 get_history_item = _wrapper.get_history_item
 remove_history_item = _wrapper.remove_history_item
 replace_history_item = _wrapper.replace_history_item
+set_auto_history = _wrapper.set_auto_history
 add_history = _wrapper.add_history
 set_startup_hook = _wrapper.set_startup_hook
 get_line_buffer = _wrapper.get_line_buffer

testing/test_readline.py

@@ -105,3 +105,15 @@ def replace(cls, *args):
 
     with open(str(histfile), "r") as f:
         assert f.readlines() == ["foo\n", "bar\n"]
+
+
+@pytest.mark.parametrize('auto_history,expected', [(True, 1), (False, 0)])
+def test_set_auto_history(auto_history, expected):
+    master, slave = pty.openpty()
+    readline_wrapper = _ReadlineWrapper(slave, slave)
+    readline_wrapper.set_auto_history(auto_history)
+
+    os.write(master, b'input\n')
+    readline_wrapper.get_reader().readline()
+
+    assert readline_wrapper.get_current_history_length() == expected