cpython/Lib/test/test_readline.py

"""
Very minimal unittests for parts of the readline module.
"""
import locale
import os
import sys
import tempfile
import textwrap
import unittest
from test.support import verbose
from test.support.import_helper import import_module
from test.support.os_helper import unlink, temp_dir, TESTFN
from test.support.pty_helper import run_pty
from test.support.script_helper import assert_python_ok
from test.support.threading_helper import requires_working_threading

# Skip tests if there is no readline module
readline = import_module('readline')

if hasattr(readline, "_READLINE_LIBRARY_VERSION"):
    is_editline = ("EditLine wrapper" in readline._READLINE_LIBRARY_VERSION)
else:
    is_editline = readline.backend == "editline"


def setUpModule():
    if verbose:
        # Python implementations other than CPython may not have
        # these private attributes
        if hasattr(readline, "_READLINE_VERSION"):
            print(f"readline version: {readline._READLINE_VERSION:#x}")
            print(f"readline runtime version: {readline._READLINE_RUNTIME_VERSION:#x}")
        if hasattr(readline, "_READLINE_LIBRARY_VERSION"):
            print(f"readline library version: {readline._READLINE_LIBRARY_VERSION!r}")
        print(f"use libedit emulation? {is_editline}")


@unittest.skipUnless(hasattr(readline, "clear_history"),
                     "The history update test cannot be run because the "
                     "clear_history method is not available.")
class TestHistoryManipulation (unittest.TestCase):
    """
    These tests were added to check that the libedit emulation on OSX and the
    "real" readline have the same interface for history manipulation. That's
    why the tests cover only a small subset of the interface.
    """

    def testHistoryUpdates(self):
        readline.clear_history()

        readline.add_history("first line")
        readline.add_history("second line")

        self.assertEqual(readline.get_history_item(0), None)
        self.assertEqual(readline.get_history_item(1), "first line")
        self.assertEqual(readline.get_history_item(2), "second line")

        readline.replace_history_item(0, "replaced line")
        self.assertEqual(readline.get_history_item(0), None)
        self.assertEqual(readline.get_history_item(1), "replaced line")
        self.assertEqual(readline.get_history_item(2), "second line")

        self.assertEqual(readline.get_current_history_length(), 2)

        readline.remove_history_item(0)
        self.assertEqual(readline.get_history_item(0), None)
        self.assertEqual(readline.get_history_item(1), "second line")

        self.assertEqual(readline.get_current_history_length(), 1)

    @unittest.skipUnless(hasattr(readline, "append_history_file"),
                         "append_history not available")
    def test_write_read_append(self):
        hfile = tempfile.NamedTemporaryFile(delete=False)
        hfile.close()
        hfilename = hfile.name
        self.addCleanup(unlink, hfilename)

        # test write-clear-read == nop
        readline.clear_history()
        readline.add_history("first line")
        readline.add_history("second line")
        readline.write_history_file(hfilename)

        readline.clear_history()
        self.assertEqual(readline.get_current_history_length(), 0)

        readline.read_history_file(hfilename)
        self.assertEqual(readline.get_current_history_length(), 2)
        self.assertEqual(readline.get_history_item(1), "first line")
        self.assertEqual(readline.get_history_item(2), "second line")

        # test append
        readline.append_history_file(1, hfilename)
        readline.clear_history()
        readline.read_history_file(hfilename)
        self.assertEqual(readline.get_current_history_length(), 3)
        self.assertEqual(readline.get_history_item(1), "first line")
        self.assertEqual(readline.get_history_item(2), "second line")
        self.assertEqual(readline.get_history_item(3), "second line")

        # test 'no such file' behaviour
        os.unlink(hfilename)
        try:
            readline.append_history_file(1, hfilename)
        except FileNotFoundError:
            pass  # Some implementations return this error (libreadline).
        else:
            os.unlink(hfilename)  # Some create it anyways (libedit).
            # If the file wasn't created, unlink will fail.
        # We're just testing that one of the two expected behaviors happens
        # instead of an incorrect error.

        # write_history_file can create the target
        readline.write_history_file(hfilename)

        # Negative values should be disallowed
        with self.assertRaises(ValueError):
            readline.append_history_file(-42, hfilename)

        # See gh-122431, using the minimum signed integer value caused a segfault
        with self.assertRaises(ValueError):
            readline.append_history_file(-2147483648, hfilename)

    def test_nonascii_history(self):
        readline.clear_history()
        try:
            readline.add_history("entrée 1")
        except UnicodeEncodeError as err:
            self.skipTest("Locale cannot encode test data: " + format(err))
        readline.add_history("entrée 2")
        readline.replace_history_item(1, "entrée 22")
        readline.write_history_file(TESTFN)
        self.addCleanup(os.remove, TESTFN)
        readline.clear_history()
        readline.read_history_file(TESTFN)
        if is_editline:
            # An add_history() call seems to be required for get_history_
            # item() to register items from the file
            readline.add_history("dummy")
        self.assertEqual(readline.get_history_item(1), "entrée 1")
        self.assertEqual(readline.get_history_item(2), "entrée 22")

    def test_write_read_limited_history(self):
        previous_length = readline.get_history_length()
        self.addCleanup(readline.set_history_length, previous_length)

        readline.clear_history()
        readline.add_history("first line")
        readline.add_history("second line")
        readline.add_history("third line")

        readline.set_history_length(2)
        self.assertEqual(readline.get_history_length(), 2)
        readline.write_history_file(TESTFN)
        self.addCleanup(os.remove, TESTFN)

        readline.clear_history()
        self.assertEqual(readline.get_current_history_length(), 0)
        self.assertEqual(readline.get_history_length(), 2)

        readline.read_history_file(TESTFN)
        self.assertEqual(readline.get_history_item(1), "second line")
        self.assertEqual(readline.get_history_item(2), "third line")
        self.assertEqual(readline.get_history_item(3), None)

        # Readline seems to report an additional history element.
        self.assertIn(readline.get_current_history_length(), (2, 3))


class TestReadline(unittest.TestCase):

    @unittest.skipIf(readline._READLINE_VERSION < 0x0601 and not is_editline,
                     "not supported in this library version")
    def test_init(self):
        # Issue #19884: Ensure that the ANSI sequence "\033[1034h" is not
        # written into stdout when the readline module is imported and stdout
        # is redirected to a pipe.
        rc, stdout, stderr = assert_python_ok('-c', 'import readline',
                                              TERM='xterm-256color')
        self.assertEqual(stdout, b'')

    def test_backend(self):
        self.assertIn(readline.backend, ("readline", "editline"))

    auto_history_script = """\
import readline
readline.set_auto_history({})
input()
print("History length:", readline.get_current_history_length())
"""

    def test_auto_history_enabled(self):
        output = run_pty(self.auto_history_script.format(True))
        # bpo-44949: Sometimes, the newline character is not written at the
        # end, so don't expect it in the output.
        self.assertIn(b"History length: 1", output)

    def test_auto_history_disabled(self):
        output = run_pty(self.auto_history_script.format(False))
        # bpo-44949: Sometimes, the newline character is not written at the
        # end, so don't expect it in the output.
        self.assertIn(b"History length: 0", output)

    def test_set_complete_delims(self):
        script = textwrap.dedent("""
            import readline
            def complete(text, state):
                if state == 0 and text == "$":
                    return "$complete"
                return None
            if readline.backend == "editline":
                readline.parse_and_bind(r'bind "\\t" rl_complete')
            else:
                readline.parse_and_bind(r'"\\t": complete')
            readline.set_completer_delims(" \\t\\n")
            readline.set_completer(complete)
            print(input())
        """)

        output = run_pty(script, input=b"$\t\n")
        self.assertIn(b"$complete", output)

    def test_nonascii(self):
        loc = locale.setlocale(locale.LC_CTYPE, None)
        if loc in ('C', 'POSIX'):
            # bpo-29240: On FreeBSD, if the LC_CTYPE locale is C or POSIX,
            # writing and reading non-ASCII bytes into/from a TTY works, but
            # readline or ncurses ignores non-ASCII bytes on read.
            self.skipTest(f"the LC_CTYPE locale is {loc!r}")

        try:
            readline.add_history("\xEB\xEF")
        except UnicodeEncodeError as err:
            self.skipTest("Locale cannot encode test data: " + format(err))

        script = r"""import readline

is_editline = readline.backend == "editline"
inserted = "[\xEFnserted]"
macro = "|t\xEB[after]"
set_pre_input_hook = getattr(readline, "set_pre_input_hook", None)
if is_editline or not set_pre_input_hook:
    # The insert_line() call via pre_input_hook() does nothing with Editline,
    # so include the extra text that would have been inserted here
    macro = inserted + macro

if is_editline:
    readline.parse_and_bind(r'bind ^B ed-prev-char')
    readline.parse_and_bind(r'bind "\t" rl_complete')
    readline.parse_and_bind(r'bind -s ^A "{}"'.format(macro))
else:
    readline.parse_and_bind(r'Control-b: backward-char')
    readline.parse_and_bind(r'"\t": complete')
    readline.parse_and_bind(r'set disable-completion off')
    readline.parse_and_bind(r'set show-all-if-ambiguous off')
    readline.parse_and_bind(r'set show-all-if-unmodified off')
    readline.parse_and_bind(r'Control-a: "{}"'.format(macro))

def pre_input_hook():
    readline.insert_text(inserted)
    readline.redisplay()
if set_pre_input_hook:
    set_pre_input_hook(pre_input_hook)

def completer(text, state):
    if text == "t\xEB":
        if state == 0:
            print("text", ascii(text))
            print("line", ascii(readline.get_line_buffer()))
            print("indexes", readline.get_begidx(), readline.get_endidx())
            return "t\xEBnt"
        if state == 1:
            return "t\xEBxt"
    if text == "t\xEBx" and state == 0:
        return "t\xEBxt"
    return None
readline.set_completer(completer)

def display(substitution, matches, longest_match_length):
    print("substitution", ascii(substitution))
    print("matches", ascii(matches))
readline.set_completion_display_matches_hook(display)

print("result", ascii(input()))
print("history", ascii(readline.get_history_item(1)))
"""

        input = b"\x01"  # Ctrl-A, expands to "|t\xEB[after]"
        input += b"\x02" * len("[after]")  # Move cursor back
        input += b"\t\t"  # Display possible completions
        input += b"x\t"  # Complete "t\xEBx" -> "t\xEBxt"
        input += b"\r"
        output = run_pty(script, input)
        self.assertIn(b"text 't\\xeb'\r\n", output)
        self.assertIn(b"line '[\\xefnserted]|t\\xeb[after]'\r\n", output)
        if sys.platform == "darwin" or not is_editline:
            self.assertIn(b"indexes 11 13\r\n", output)
            # Non-macOS libedit does not handle non-ASCII bytes
            # the same way and generates character indices
            # rather than byte indices via get_begidx() and
            # get_endidx().  Ex: libedit2 3.1-20191231-2 on Debian
            # winds up with "indexes 10 12".  Stemming from the
            # start and end values calls back into readline.c's
            # rl_attempted_completion_function = flex_complete with:
            # (11, 13) instead of libreadline's (12, 15).

        if not is_editline and hasattr(readline, "set_pre_input_hook"):
            self.assertIn(b"substitution 't\\xeb'\r\n", output)
            self.assertIn(b"matches ['t\\xebnt', 't\\xebxt']\r\n", output)
        expected = br"'[\xefnserted]|t\xebxt[after]'"
        self.assertIn(b"result " + expected + b"\r\n", output)
        # bpo-45195: Sometimes, the newline character is not written at the
        # end, so don't expect it in the output.
        self.assertIn(b"history " + expected, output)

    # We have 2 reasons to skip this test:
    # - readline: history size was added in 6.0
    #   See https://cnswww.cns.cwru.edu/php/chet/readline/CHANGES
    # - editline: history size is broken on OS X 10.11.6.
    #   Newer versions were not tested yet.
    @unittest.skipIf(readline._READLINE_VERSION < 0x600,
                     "this readline version does not support history-size")
    @unittest.skipIf(is_editline,
                     "editline history size configuration is broken")
    def test_history_size(self):
        history_size = 10
        with temp_dir() as test_dir:
            inputrc = os.path.join(test_dir, "inputrc")
            with open(inputrc, "wb") as f:
                f.write(b"set history-size %d\n" % history_size)

            history_file = os.path.join(test_dir, "history")
            with open(history_file, "wb") as f:
                # history_size * 2 items crashes readline
                data = b"".join(b"item %d\n" % i
                                for i in range(history_size * 2))
                f.write(data)

            script = """
import os
import readline

history_file = os.environ["HISTORY_FILE"]
readline.read_history_file(history_file)
input()
readline.write_history_file(history_file)
"""

            env = dict(os.environ)
            env["INPUTRC"] = inputrc
            env["HISTORY_FILE"] = history_file

            run_pty(script, input=b"last input\r", env=env)

            with open(history_file, "rb") as f:
                lines = f.readlines()
            self.assertEqual(len(lines), history_size)
            self.assertEqual(lines[-1].strip(), b"last input")

    @requires_working_threading()
    def test_gh123321_threadsafe(self):
        """gh-123321: readline should be thread-safe and not crash"""
        script = textwrap.dedent(r"""
            import threading
            from test.support.threading_helper import join_thread

            def func():
                input()

            thread1 = threading.Thread(target=func)
            thread2 = threading.Thread(target=func)
            thread1.start()
            thread2.start()
            join_thread(thread1)
            join_thread(thread2)
            print("done")
        """)

        output = run_pty(script, input=b"input1\rinput2\r")

        self.assertIn(b"done", output)


    def test_write_read_limited_history(self):
        previous_length = readline.get_history_length()
        self.addCleanup(readline.set_history_length, previous_length)

        readline.add_history("first line")
        readline.add_history("second line")
        readline.add_history("third line")

        readline.set_history_length(2)
        self.assertEqual(readline.get_history_length(), 2)
        readline.write_history_file(TESTFN)
        self.addCleanup(os.remove, TESTFN)

        readline.read_history_file(TESTFN)
        # Without clear_history() there's no good way to test if
        # the correct entries are present (we're combining history limiting and
        # possible deduplication with arbitrary previous content).
        # So, we've only tested that the read did not fail.
        # See TestHistoryManipulation for the full test.


if __name__ == "__main__":
    unittest.main()