"""Utility functions with no non-trivial dependencies."""
from __future__ import annotations
import hashlib
import io
import os
import pathlib
import re
import shutil
import sys
import time
from importlib import resources as importlib_resources
from typing import IO, Callable, Container, Final, Iterable, Sequence, Sized, TypeVar
from typing_extensions import Literal
try:
import curses
import _curses # noqa: F401
CURSES_ENABLED = True
except ImportError:
CURSES_ENABLED = False
T = TypeVar("T")
if sys.version_info >= (3, 9):
TYPESHED_DIR: Final = str(importlib_resources.files("mypy") / "typeshed")
else:
with importlib_resources.path(
"mypy", # mypy-c doesn't support __package__
"py.typed", # a marker file for type information, we assume typeshed to live in the same dir
) as _resource:
TYPESHED_DIR = str(_resource.parent / "typeshed")
ENCODING_RE: Final = re.compile(rb"([ \t\v]*#.*(\r\n?|\n))??[ \t\v]*#.*coding[:=][ \t]*([-\w.]+)")
DEFAULT_SOURCE_OFFSET: Final = 4
DEFAULT_COLUMNS: Final = 80
# At least this number of columns will be shown on each side of
# error location when printing source code snippet.
MINIMUM_WIDTH: Final = 20
# VT100 color code processing was added in Windows 10, but only the second major update,
# Threshold 2. Fortunately, everyone (even on LTSB, Long Term Support Branch) should
# have a version of Windows 10 newer than this. Note that Windows 8 and below are not
# supported, but are either going out of support, or make up only a few % of the market.
MINIMUM_WINDOWS_MAJOR_VT100: Final = 10
MINIMUM_WINDOWS_BUILD_VT100: Final = 10586
SPECIAL_DUNDERS: Final = frozenset(
("__init__", "__new__", "__call__", "__init_subclass__", "__class_getitem__")
)
def is_dunder(name: str, exclude_special: bool = False) -> bool:
"""Returns whether name is a dunder name.
Args:
exclude_special: Whether to return False for a couple special dunder methods.
"""
if exclude_special and name in SPECIAL_DUNDERS:
return False
return name.startswith("__") and name.endswith("__")
def is_sunder(name: str) -> bool:
return not is_dunder(name) and name.startswith("_") and name.endswith("_")
def split_module_names(mod_name: str) -> list[str]:
"""Return the module and all parent module names.
So, if `mod_name` is 'a.b.c', this function will return
['a.b.c', 'a.b', and 'a'].
"""
out = [mod_name]
while "." in mod_name:
mod_name = mod_name.rsplit(".", 1)[0]
out.append(mod_name)
return out
def module_prefix(modules: Iterable[str], target: str) -> str | None:
result = split_target(modules, target)
if result is None:
return None
return result[0]
def split_target(modules: Iterable[str], target: str) -> tuple[str, str] | None:
remaining: list[str] = []
while True:
if target in modules:
return target, ".".join(remaining)
components = target.rsplit(".", 1)
if len(components) == 1:
return None
target = components[0]
remaining.insert(0, components[1])
def short_type(obj: object) -> str:
"""Return the last component of the type name of an object.
If obj is None, return 'nil'. For example, if obj is 1, return 'int'.
"""
if obj is None:
return "nil"
t = str(type(obj))
return t.split(".")[-1].rstrip("'>")
def find_python_encoding(text: bytes) -> tuple[str, int]:
"""PEP-263 for detecting Python file encoding"""
result = ENCODING_RE.match(text)
if result:
line = 2 if result.group(1) else 1
encoding = result.group(3).decode("ascii")
# Handle some aliases that Python is happy to accept and that are used in the wild.
if encoding.startswith(("iso-latin-1-", "latin-1-")) or encoding == "iso-latin-1":
encoding = "latin-1"
return encoding, line
else:
default_encoding = "utf8"
return default_encoding, -1
def bytes_to_human_readable_repr(b: bytes) -> str:
"""Converts bytes into some human-readable representation. Unprintable
bytes such as the nul byte are escaped. For example:
>>> b = bytes([102, 111, 111, 10, 0])
>>> s = bytes_to_human_readable_repr(b)
>>> print(s)
foo\n\x00
>>> print(repr(s))
'foo\\n\\x00'
"""
return repr(b)[2:-1]
class DecodeError(Exception):
"""Exception raised when a file cannot be decoded due to an unknown encoding type.
Essentially a wrapper for the LookupError raised by `bytearray.decode`
"""
def decode_python_encoding(source: bytes) -> str:
"""Read the Python file with while obeying PEP-263 encoding detection.
Returns the source as a string.
"""
# check for BOM UTF-8 encoding and strip it out if present
if source.startswith(b"\xef\xbb\xbf"):
encoding = "utf8"
source = source[3:]
else:
# look at first two lines and check if PEP-263 coding is present
encoding, _ = find_python_encoding(source)
try:
source_text = source.decode(encoding)
except LookupError as lookuperr:
raise DecodeError(str(lookuperr)) from lookuperr
return source_text
def read_py_file(path: str, read: Callable[[str], bytes]) -> list[str] | None:
"""Try reading a Python file as list of source lines.
Return None if something goes wrong.
"""
try:
source = read(path)
except OSError:
return None
else:
try:
source_lines = decode_python_encoding(source).splitlines()
except DecodeError:
return None
return source_lines
def trim_source_line(line: str, max_len: int, col: int, min_width: int) -> tuple[str, int]:
"""Trim a line of source code to fit into max_len.
Show 'min_width' characters on each side of 'col' (an error location). If either
start or end is trimmed, this is indicated by adding '...' there.
A typical result looks like this:
...some_variable = function_to_call(one_arg, other_arg) or...
Return the trimmed string and the column offset to to adjust error location.
"""
if max_len < 2 * min_width + 1:
# In case the window is too tiny it is better to still show something.
max_len = 2 * min_width + 1
# Trivial case: line already fits in.
if len(line) <= max_len:
return line, 0
# If column is not too large so that there is still min_width after it,
# the line doesn't need to be trimmed at the start.
if col + min_width < max_len:
return line[:max_len] + "...", 0
# Otherwise, if the column is not too close to the end, trim both sides.
if col < len(line) - min_width - 1:
offset = col - max_len + min_width + 1
return "..." + line[offset : col + min_width + 1] + "...", offset - 3
# Finally, if the column is near the end, just trim the start.
return "..." + line[-max_len:], len(line) - max_len - 3
def get_mypy_comments(source: str) -> list[tuple[int, str]]:
PREFIX = "# mypy: "
# Don't bother splitting up the lines unless we know it is useful
if PREFIX not in source:
return []
lines = source.split("\n")
results = []
for i, line in enumerate(lines):
if line.startswith(PREFIX):
results.append((i + 1, line[len(PREFIX) :]))
return results
PASS_TEMPLATE: Final = """
"""
FAIL_TEMPLATE: Final = """
{text}
"""
ERROR_TEMPLATE: Final = """
{text}
"""
def write_junit_xml(
dt: float, serious: bool, messages: list[str], path: str, version: str, platform: str
) -> None:
from xml.sax.saxutils import escape
if not messages and not serious:
xml = PASS_TEMPLATE.format(time=dt, ver=version, platform=platform)
elif not serious:
xml = FAIL_TEMPLATE.format(
text=escape("\n".join(messages)), time=dt, ver=version, platform=platform
)
else:
xml = ERROR_TEMPLATE.format(
text=escape("\n".join(messages)), time=dt, ver=version, platform=platform
)
# checks for a directory structure in path and creates folders if needed
xml_dirs = os.path.dirname(os.path.abspath(path))
if not os.path.isdir(xml_dirs):
os.makedirs(xml_dirs)
with open(path, "wb") as f:
f.write(xml.encode("utf-8"))
class IdMapper:
"""Generate integer ids for objects.
Unlike id(), these start from 0 and increment by 1, and ids won't
get reused across the life-time of IdMapper.
Assume objects don't redefine __eq__ or __hash__.
"""
def __init__(self) -> None:
self.id_map: dict[object, int] = {}
self.next_id = 0
def id(self, o: object) -> int:
if o not in self.id_map:
self.id_map[o] = self.next_id
self.next_id += 1
return self.id_map[o]
def get_prefix(fullname: str) -> str:
"""Drop the final component of a qualified name (e.g. ('x.y' -> 'x')."""
return fullname.rsplit(".", 1)[0]
def correct_relative_import(
cur_mod_id: str, relative: int, target: str, is_cur_package_init_file: bool
) -> tuple[str, bool]:
if relative == 0:
return target, True
parts = cur_mod_id.split(".")
rel = relative
if is_cur_package_init_file:
rel -= 1
ok = len(parts) >= rel
if rel != 0:
cur_mod_id = ".".join(parts[:-rel])
return cur_mod_id + (("." + target) if target else ""), ok
fields_cache: Final[dict[type[object], list[str]]] = {}
def get_class_descriptors(cls: type[object]) -> Sequence[str]:
import inspect # Lazy import for minor startup speed win
# Maintain a cache of type -> attributes defined by descriptors in the class
# (that is, attributes from __slots__ and C extension classes)
if cls not in fields_cache:
members = inspect.getmembers(
cls, lambda o: inspect.isgetsetdescriptor(o) or inspect.ismemberdescriptor(o)
)
fields_cache[cls] = [x for x, y in members if x != "__weakref__" and x != "__dict__"]
return fields_cache[cls]
def replace_object_state(
new: object, old: object, copy_dict: bool = False, skip_slots: tuple[str, ...] = ()
) -> None:
"""Copy state of old node to the new node.
This handles cases where there is __dict__ and/or attribute descriptors
(either from slots or because the type is defined in a C extension module).
Assume that both objects have the same __class__.
"""
if hasattr(old, "__dict__"):
if copy_dict:
new.__dict__ = dict(old.__dict__)
else:
new.__dict__ = old.__dict__
for attr in get_class_descriptors(old.__class__):
if attr in skip_slots:
continue
try:
if hasattr(old, attr):
setattr(new, attr, getattr(old, attr))
elif hasattr(new, attr):
delattr(new, attr)
# There is no way to distinguish getsetdescriptors that allow
# writes from ones that don't (I think?), so we just ignore
# AttributeErrors if we need to.
# TODO: What about getsetdescriptors that act like properties???
except AttributeError:
pass
def is_sub_path(path1: str, path2: str) -> bool:
"""Given two paths, return if path1 is a sub-path of path2."""
return pathlib.Path(path2) in pathlib.Path(path1).parents
def hard_exit(status: int = 0) -> None:
"""Kill the current process without fully cleaning up.
This can be quite a bit faster than a normal exit() since objects are not freed.
"""
sys.stdout.flush()
sys.stderr.flush()
os._exit(status)
def unmangle(name: str) -> str:
"""Remove internal suffixes from a short name."""
return name.rstrip("'")
def get_unique_redefinition_name(name: str, existing: Container[str]) -> str:
"""Get a simple redefinition name not present among existing.
For example, for name 'foo' we try 'foo-redefinition', 'foo-redefinition2',
'foo-redefinition3', etc. until we find one that is not in existing.
"""
r_name = name + "-redefinition"
if r_name not in existing:
return r_name
i = 2
while r_name + str(i) in existing:
i += 1
return r_name + str(i)
def check_python_version(program: str) -> None:
"""Report issues with the Python used to run mypy, dmypy, or stubgen"""
# Check for known bad Python versions.
if sys.version_info[:2] < (3, 8):
sys.exit(
"Running {name} with Python 3.7 or lower is not supported; "
"please upgrade to 3.8 or newer".format(name=program)
)
def count_stats(messages: list[str]) -> tuple[int, int, int]:
"""Count total number of errors, notes and error_files in message list."""
errors = [e for e in messages if ": error:" in e]
error_files = {e.split(":")[0] for e in errors}
notes = [e for e in messages if ": note:" in e]
return len(errors), len(notes), len(error_files)
def split_words(msg: str) -> list[str]:
"""Split line of text into words (but not within quoted groups)."""
next_word = ""
res: list[str] = []
allow_break = True
for c in msg:
if c == " " and allow_break:
res.append(next_word)
next_word = ""
continue
if c == '"':
allow_break = not allow_break
next_word += c
res.append(next_word)
return res
def get_terminal_width() -> int:
"""Get current terminal width if possible, otherwise return the default one."""
return (
int(os.getenv("MYPY_FORCE_TERMINAL_WIDTH", "0"))
or shutil.get_terminal_size().columns
or DEFAULT_COLUMNS
)
def soft_wrap(msg: str, max_len: int, first_offset: int, num_indent: int = 0) -> str:
"""Wrap a long error message into few lines.
Breaks will only happen between words, and never inside a quoted group
(to avoid breaking types such as "Union[int, str]"). The 'first_offset' is
the width before the start of first line.
Pad every next line with 'num_indent' spaces. Every line will be at most 'max_len'
characters, except if it is a single word or quoted group.
For example:
first_offset
------------------------
path/to/file: error: 58: Some very long error message
that needs to be split in separate lines.
"Long[Type, Names]" are never split.
^^^^--------------------------------------------------
num_indent max_len
"""
words = split_words(msg)
next_line = words.pop(0)
lines: list[str] = []
while words:
next_word = words.pop(0)
max_line_len = max_len - num_indent if lines else max_len - first_offset
# Add 1 to account for space between words.
if len(next_line) + len(next_word) + 1 <= max_line_len:
next_line += " " + next_word
else:
lines.append(next_line)
next_line = next_word
lines.append(next_line)
padding = "\n" + " " * num_indent
return padding.join(lines)
def hash_digest(data: bytes) -> str:
"""Compute a hash digest of some data.
We use a cryptographic hash because we want a low probability of
accidental collision, but we don't really care about any of the
cryptographic properties.
"""
# Once we drop Python 3.5 support, we should consider using
# blake2b, which is faster.
return hashlib.sha256(data).hexdigest()
def parse_gray_color(cup: bytes) -> str:
"""Reproduce a gray color in ANSI escape sequence"""
if sys.platform == "win32":
assert False, "curses is not available on Windows"
set_color = "".join([cup[:-1].decode(), "m"])
gray = curses.tparm(set_color.encode("utf-8"), 1, 9).decode()
return gray
def should_force_color() -> bool:
env_var = os.getenv("MYPY_FORCE_COLOR", os.getenv("FORCE_COLOR", "0"))
try:
return bool(int(env_var))
except ValueError:
return bool(env_var)
class FancyFormatter:
"""Apply color and bold font to terminal output.
This currently only works on Linux and Mac.
"""
def __init__(self, f_out: IO[str], f_err: IO[str], hide_error_codes: bool) -> None:
self.hide_error_codes = hide_error_codes
# Check if we are in a human-facing terminal on a supported platform.
if sys.platform not in ("linux", "darwin", "win32", "emscripten"):
self.dummy_term = True
return
if not should_force_color() and (not f_out.isatty() or not f_err.isatty()):
self.dummy_term = True
return
if sys.platform == "win32":
self.dummy_term = not self.initialize_win_colors()
elif sys.platform == "emscripten":
self.dummy_term = not self.initialize_vt100_colors()
else:
self.dummy_term = not self.initialize_unix_colors()
if not self.dummy_term:
self.colors = {
"red": self.RED,
"green": self.GREEN,
"blue": self.BLUE,
"yellow": self.YELLOW,
"none": "",
}
def initialize_vt100_colors(self) -> bool:
"""Return True if initialization was successful and we can use colors, False otherwise"""
# Windows and Emscripten can both use ANSI/VT100 escape sequences for color
assert sys.platform in ("win32", "emscripten")
self.BOLD = "\033[1m"
self.UNDER = "\033[4m"
self.BLUE = "\033[94m"
self.GREEN = "\033[92m"
self.RED = "\033[91m"
self.YELLOW = "\033[93m"
self.NORMAL = "\033[0m"
self.DIM = "\033[2m"
return True
def initialize_win_colors(self) -> bool:
"""Return True if initialization was successful and we can use colors, False otherwise"""
# Windows ANSI escape sequences are only supported on Threshold 2 and above.
# we check with an assert at runtime and an if check for mypy, as asserts do not
# yet narrow platform
assert sys.platform == "win32"
if sys.platform == "win32":
winver = sys.getwindowsversion()
if (
winver.major < MINIMUM_WINDOWS_MAJOR_VT100
or winver.build < MINIMUM_WINDOWS_BUILD_VT100
):
return False
import ctypes
kernel32 = ctypes.windll.kernel32
ENABLE_PROCESSED_OUTPUT = 0x1
ENABLE_WRAP_AT_EOL_OUTPUT = 0x2
ENABLE_VIRTUAL_TERMINAL_PROCESSING = 0x4
STD_OUTPUT_HANDLE = -11
kernel32.SetConsoleMode(
kernel32.GetStdHandle(STD_OUTPUT_HANDLE),
ENABLE_PROCESSED_OUTPUT
| ENABLE_WRAP_AT_EOL_OUTPUT
| ENABLE_VIRTUAL_TERMINAL_PROCESSING,
)
self.initialize_vt100_colors()
return True
return False
def initialize_unix_colors(self) -> bool:
"""Return True if initialization was successful and we can use colors, False otherwise"""
if sys.platform == "win32" or not CURSES_ENABLED:
return False
try:
# setupterm wants a fd to potentially write an "initialization sequence".
# We override sys.stdout for the daemon API so if stdout doesn't have an fd,
# just give it /dev/null.
try:
fd = sys.stdout.fileno()
except io.UnsupportedOperation:
with open("/dev/null", "rb") as f:
curses.setupterm(fd=f.fileno())
else:
curses.setupterm(fd=fd)
except curses.error:
# Most likely terminfo not found.
return False
bold = curses.tigetstr("bold")
under = curses.tigetstr("smul")
set_color = curses.tigetstr("setaf")
set_eseq = curses.tigetstr("cup")
normal = curses.tigetstr("sgr0")
if not (bold and under and set_color and set_eseq and normal):
return False
self.NORMAL = normal.decode()
self.BOLD = bold.decode()
self.UNDER = under.decode()
self.DIM = parse_gray_color(set_eseq)
self.BLUE = curses.tparm(set_color, curses.COLOR_BLUE).decode()
self.GREEN = curses.tparm(set_color, curses.COLOR_GREEN).decode()
self.RED = curses.tparm(set_color, curses.COLOR_RED).decode()
self.YELLOW = curses.tparm(set_color, curses.COLOR_YELLOW).decode()
return True
def style(
self,
text: str,
color: Literal["red", "green", "blue", "yellow", "none"],
bold: bool = False,
underline: bool = False,
dim: bool = False,
) -> str:
"""Apply simple color and style (underlined or bold)."""
if self.dummy_term:
return text
if bold:
start = self.BOLD
else:
start = ""
if underline:
start += self.UNDER
if dim:
start += self.DIM
return start + self.colors[color] + text + self.NORMAL
def fit_in_terminal(
self, messages: list[str], fixed_terminal_width: int | None = None
) -> list[str]:
"""Improve readability by wrapping error messages and trimming source code."""
width = fixed_terminal_width or get_terminal_width()
new_messages = messages.copy()
for i, error in enumerate(messages):
if ": error:" in error:
loc, msg = error.split("error:", maxsplit=1)
msg = soft_wrap(msg, width, first_offset=len(loc) + len("error: "))
new_messages[i] = loc + "error:" + msg
if error.startswith(" " * DEFAULT_SOURCE_OFFSET) and "^" not in error:
# TODO: detecting source code highlights through an indent can be surprising.
# Restore original error message and error location.
error = error[DEFAULT_SOURCE_OFFSET:]
marker_line = messages[i + 1]
marker_column = marker_line.index("^")
column = marker_column - DEFAULT_SOURCE_OFFSET
if "~" not in marker_line:
marker = "^"
else:
# +1 because both ends are included
marker = marker_line[marker_column : marker_line.rindex("~") + 1]
# Let source have some space also on the right side, plus 6
# to accommodate ... on each side.
max_len = width - DEFAULT_SOURCE_OFFSET - 6
source_line, offset = trim_source_line(error, max_len, column, MINIMUM_WIDTH)
new_messages[i] = " " * DEFAULT_SOURCE_OFFSET + source_line
# Also adjust the error marker position and trim error marker is needed.
new_marker_line = " " * (DEFAULT_SOURCE_OFFSET + column - offset) + marker
if len(new_marker_line) > len(new_messages[i]) and len(marker) > 3:
new_marker_line = new_marker_line[: len(new_messages[i]) - 3] + "..."
new_messages[i + 1] = new_marker_line
return new_messages
def colorize(self, error: str) -> str:
"""Colorize an output line by highlighting the status and error code."""
if ": error:" in error:
loc, msg = error.split("error:", maxsplit=1)
if self.hide_error_codes:
return (
loc + self.style("error:", "red", bold=True) + self.highlight_quote_groups(msg)
)
codepos = msg.rfind("[")
if codepos != -1:
code = msg[codepos:]
msg = msg[:codepos]
else:
code = "" # no error code specified
return (
loc
+ self.style("error:", "red", bold=True)
+ self.highlight_quote_groups(msg)
+ self.style(code, "yellow")
)
elif ": note:" in error:
loc, msg = error.split("note:", maxsplit=1)
formatted = self.highlight_quote_groups(self.underline_link(msg))
return loc + self.style("note:", "blue") + formatted
elif error.startswith(" " * DEFAULT_SOURCE_OFFSET):
# TODO: detecting source code highlights through an indent can be surprising.
if "^" not in error:
return self.style(error, "none", dim=True)
return self.style(error, "red")
else:
return error
def highlight_quote_groups(self, msg: str) -> str:
"""Make groups quoted with double quotes bold (including quotes).
This is used to highlight types, attribute names etc.
"""
if msg.count('"') % 2:
# Broken error message, don't do any formatting.
return msg
parts = msg.split('"')
out = ""
for i, part in enumerate(parts):
if i % 2 == 0:
out += self.style(part, "none")
else:
out += self.style('"' + part + '"', "none", bold=True)
return out
def underline_link(self, note: str) -> str:
"""Underline a link in a note message (if any).
This assumes there is at most one link in the message.
"""
match = re.search(r"https?://\S*", note)
if not match:
return note
start = match.start()
end = match.end()
return note[:start] + self.style(note[start:end], "none", underline=True) + note[end:]
def format_success(self, n_sources: int, use_color: bool = True) -> str:
"""Format short summary in case of success.
n_sources is total number of files passed directly on command line,
i.e. excluding stubs and followed imports.
"""
msg = f"Success: no issues found in {n_sources} source file{plural_s(n_sources)}"
if not use_color:
return msg
return self.style(msg, "green", bold=True)
def format_error(
self,
n_errors: int,
n_files: int,
n_sources: int,
*,
blockers: bool = False,
use_color: bool = True,
) -> str:
"""Format a short summary in case of errors."""
msg = f"Found {n_errors} error{plural_s(n_errors)} in {n_files} file{plural_s(n_files)}"
if blockers:
msg += " (errors prevented further checking)"
else:
msg += f" (checked {n_sources} source file{plural_s(n_sources)})"
if not use_color:
return msg
return self.style(msg, "red", bold=True)
def is_typeshed_file(typeshed_dir: str | None, file: str) -> bool:
typeshed_dir = typeshed_dir if typeshed_dir is not None else TYPESHED_DIR
try:
return os.path.commonpath((typeshed_dir, os.path.abspath(file))) == typeshed_dir
except ValueError: # Different drives on Windows
return False
def is_stub_package_file(file: str) -> bool:
# Use hacky heuristics to check whether file is part of a PEP 561 stub package.
if not file.endswith(".pyi"):
return False
return any(component.endswith("-stubs") for component in os.path.split(os.path.abspath(file)))
def unnamed_function(name: str | None) -> bool:
return name is not None and name == "_"
time_ref = time.perf_counter_ns
def time_spent_us(t0: int) -> int:
return int((time.perf_counter_ns() - t0) / 1000)
def plural_s(s: int | Sized) -> str:
count = s if isinstance(s, int) else len(s)
if count != 1:
return "s"
else:
return ""
def quote_docstring(docstr: str) -> str:
"""Returns docstring correctly encapsulated in a single or double quoted form."""
# Uses repr to get hint on the correct quotes and escape everything properly.
# Creating multiline string for prettier output.
docstr_repr = "\n".join(re.split(r"(?<=[^\\])\\n", repr(docstr)))
if docstr_repr.startswith("'"):
# Enforce double quotes when it's safe to do so.
# That is when double quotes are not in the string
# or when it doesn't end with a single quote.
if '"' not in docstr_repr[1:-1] and docstr_repr[-2] != "'":
return f'"""{docstr_repr[1:-1]}"""'
return f"''{docstr_repr}''"
else:
return f'""{docstr_repr}""'