Fix typing woes

The codebase is now typechecker-friendly. Also fixed some random bugs
here and there that could have been detected with static typechecking in
place.

Author: Expertcoderz

userland/__init__.py

@@ -9,18 +9,21 @@
 
 
 def print_usage(prog_name: str) -> None:
-    try:
-        version = importlib.metadata.version(__package__)
-    except importlib.metadata.PackageNotFoundError:
-        version = "(unknown version)"
+    version = "(unknown version)"
+
+    if __package__:
+        try:
+            version = importlib.metadata.version(__package__)
+        except importlib.metadata.PackageNotFoundError:
+            pass
 
     print(
         f"python-userland v{version}",
         f"Usage: {prog_name} APPLET [ARGUMENT]...",
         f"{7 * " "}{prog_name} --list",
         "\nAvailable applets:",
         ", ".join(sorted(applets)),
-        sep="\n"
+        sep="\n",
     )
 
 

userland/core/command.py

@@ -1,14 +1,15 @@
 import sys
-from optparse import OptionParser
+from optparse import OptionParser, Values
 from typing import Any, Callable
 
 from .users import OptionParserUsersMixin
 
 
 class ExtendedOptionParser(OptionParserUsersMixin, OptionParser):
-    def __init__(self, usage: tuple[str], **kwargs):
+    def __init__(self, usage: str | tuple[str, ...], **kwargs):
         super().__init__(
-            usage="Usage: " + f"\n{7 * " "}".join(usage),
+            usage="Usage: "
+            + f"\n{7 * " "}".join(usage if isinstance(usage, tuple) else (usage,)),
             add_help_option=False,
             **kwargs,
         )
@@ -40,17 +41,12 @@ def expect_nargs(self, args: list[str], nargs: int | tuple[int] | tuple[int, int
 
 def command(parser: OptionParser | None = None):
     def create_utility(
-        func: Callable[[dict[str, Any], list[Any]], int],
+        func: Callable[[Values, list[Any]], int],
     ) -> Callable[[], None]:
-        if parser:
-
-            def execute_utility():
-                sys.exit(func(*parser.parse_args()))
-
-        else:
-
-            def execute_utility():
-                sys.exit(func({}, sys.argv[1:]))
+        def execute_utility():
+            sys.exit(
+                func(*parser.parse_args()) if parser else func(Values(), sys.argv[1:])
+            )
 
         return execute_utility
 

userland/core/io.py

@@ -1,7 +1,7 @@
 import contextlib
 import os
 import sys
-from typing import Any, Generator
+from typing import Any, Generator, IO
 
 
 def perror(*errors: Any) -> None:
@@ -12,7 +12,7 @@ def perror(*errors: Any) -> None:
 
 
 @contextlib.contextmanager
-def safe_open(*args, **kwargs):
+def safe_open(*args, **kwargs) -> Generator[IO | None]:
     try:
         with open(*args, **kwargs) as io:
             yield io

userland/core/paths.py

@@ -1,10 +1,10 @@
 import sys
 from pathlib import Path
-from typing import Generator, Literal
+from typing import Generator, Iterable, Literal
 
 
 def traverse_files(
-    filenames: list[str],
+    filenames: Iterable[str],
     recurse_mode: Literal["L", "H", "P"] | None = None,
     preserve_root: bool = False,
 ) -> Generator[Path | None]:

userland/utilities/basename.py

@@ -26,7 +26,7 @@
 
 
 @core.command(parser)
-def python_userland_basename(opts, args):
+def python_userland_basename(opts, args: list[str]):
     parser.expect_nargs(args, (1,))
 
     if opts.suffix:

userland/utilities/cat.py

@@ -1,15 +1,15 @@
 import itertools
 import sys
 from io import BufferedReader
-from typing import BinaryIO, Generator
+from typing import Generator, Iterable
 
 from .. import core
 
 
-def squeeze_blank_lines(io: BinaryIO) -> Generator[bytes]:
+def squeeze_blank_lines(stream: Iterable[bytes]) -> Generator[bytes]:
     was_blank = False
 
-    for line in io:
+    for line in stream:
         is_blank = len(line) < 2
 
         if was_blank and is_blank:
@@ -19,14 +19,14 @@ def squeeze_blank_lines(io: BinaryIO) -> Generator[bytes]:
         was_blank = is_blank
 
 
-def number_lines(io: BinaryIO) -> Generator[bytes]:
-    for i, _ in enumerate(io):
+def number_lines(stream: Iterable[bytes]) -> Generator[bytes]:
+    for i, _ in enumerate(stream):
         yield f"{i + 1:>6}  ".encode()
 
 
-def number_nonblank_lines(io: BinaryIO) -> Generator[bytes]:
+def number_nonblank_lines(stream: Iterable[bytes]) -> Generator[bytes]:
     i = 1
-    for line in io:
+    for line in stream:
         if len(line) > 1:
             yield f"{i:>6}  ".encode()
             i += 1
@@ -62,16 +62,16 @@ def format_chars(
         yield n.to_bytes()
 
 
-def format_lines(io: BinaryIO, *args) -> Generator[bytes]:
-    for line in io:
+def format_lines(stream: Iterable[bytes], *args) -> Generator[bytes]:
+    for line in stream:
         yield b"".join(format_chars(line, *args))
 
 
-def cat_io(opts, io: BinaryIO) -> None:
+def cat_io(opts, stream: Iterable[bytes]) -> None:
     if opts.squeeze_blank:
-        io = squeeze_blank_lines(io)
+        stream = squeeze_blank_lines(stream)
 
-    io1, io2 = itertools.tee(io, 2)
+    io1, io2 = itertools.tee(stream, 2)
     gen1, gen2 = None, None
 
     if opts.number_nonblank:
@@ -95,7 +95,7 @@ def cat_io(opts, io: BinaryIO) -> None:
 
 
 parser = core.ExtendedOptionParser(
-    usage=("%prog [OPTION]... [FILE]...",),
+    usage="%prog [OPTION]... [FILE]...",
     description="Concatenate each FILE to standard output.",
 )
 
@@ -134,7 +134,7 @@ def cat_io(opts, io: BinaryIO) -> None:
 
 
 @core.command(parser)
-def python_userland_cat(opts, args):
+def python_userland_cat(opts, args: list[str]):
     if opts.show_all:
         opts.show_ends = True
         opts.show_tabs = True
@@ -146,26 +146,26 @@ def python_userland_cat(opts, args):
         opts.show_tabs = True
         opts.show_nonprinting = True
 
-    generators: list[Generator[bytes]] = []
+    streams: list[Iterable[bytes]] = []
     failed = False
 
     for name in args or ["-"]:
         if name == "-":
-            generators.append(core.readlines_stdin_raw())
+            streams.append(core.readlines_stdin_raw())
         else:
             try:
-                generators.append(open(name, "rb"))
+                streams.append(open(name, "rb"))
             except OSError as e:
                 failed = True
                 core.perror(e)
 
     try:
-        cat_io(opts, itertools.chain(*generators))
+        cat_io(opts, itertools.chain(*streams))
     except KeyboardInterrupt:
         print()
         return 130
     finally:
-        for gen in generators:
+        for gen in streams:
             # Close opened files other than stdin.
             if isinstance(gen, BufferedReader):
                 gen.close()

userland/utilities/chgrp.py

@@ -125,7 +125,7 @@
 
 
 @core.command(parser)
-def python_userland_chgrp(opts, args):
+def python_userland_chgrp(opts, args: list[str]):
     parser.expect_nargs(args, (1,))
 
     from_uid: int | None = None

userland/utilities/chown.py

@@ -126,7 +126,7 @@
 
 
 @core.command(parser)
-def python_userland_chown(opts, args):
+def python_userland_chown(opts, args: list[str]):
     parser.expect_nargs(args, (1,))
 
     from_uid: int | None = None
@@ -137,6 +137,8 @@ def python_userland_chown(opts, args):
 
     chown_args = {"follow_symlinks": opts.dereference}
 
+    owner_spec: str
+
     if opts.reference:
         try:
             ref_stat = Path(opts.reference).stat(follow_symlinks=True)
@@ -146,6 +148,12 @@ def python_userland_chown(opts, args):
 
         chown_args["user"] = ref_stat.st_uid
         chown_args["group"] = ref_stat.st_gid
+
+        owner_spec = (
+            core.user_display_name_from_id(ref_stat.st_uid)
+            + ":"
+            + core.group_display_name_from_id(ref_stat.st_gid)
+        )
     else:
         parser.expect_nargs(args, (2,))
         owner_spec = args.pop(0)

userland/utilities/clear.py

@@ -4,7 +4,7 @@
 # clear(1), roughly modelled off the ncurses implementation.
 
 parser = core.ExtendedOptionParser(
-    usage=("%prog [OPTION]...",),
+    usage="%prog [OPTION]...",
     description="Clear the terminal screen.",
 )
 
@@ -14,7 +14,7 @@
 
 
 @core.command(parser)
-def python_userland_clear(opts, args):
+def python_userland_clear(opts, args: list[str]):
     if args:
         return 1
 

userland/utilities/dirname.py

@@ -4,7 +4,7 @@
 
 
 parser = core.ExtendedOptionParser(
-    usage=("%prog [OPTION]... NAME...",),
+    usage="%prog [OPTION]... NAME...",
     description=(
         "Print each path NAME with the last component removed,"
         " or '.' if NAME is the only component."
@@ -20,7 +20,7 @@
 
 
 @core.command(parser)
-def python_userland_dirname(opts, args):
+def python_userland_dirname(opts, args: list[str]):
     parser.expect_nargs(args, (1,))
 
     for path in map(PurePath, args):