Purge typing.Text and typing.ContextManager from third-party stubs no longer supporting Python 2

[AlexWaygood]

I do love a good codemod.

Accomplished using the following script.

#!/usr/bin/env python3

import ast
import re
import subprocess
import sys
from itertools import chain
from pathlib import Path
from typing import NamedTuple


class DeleteableImport(NamedTuple):
    old: str
    replacement: str


FAILURES = []


def fix_bad_syntax(path: Path) -> None:
    with open(path) as f:
        stub = f.read()

    lines = stub.splitlines()
    tree = ast.parse(stub)
    imports_to_delete = {}
    text_from_typing = False

    class BadImportFinder(ast.NodeVisitor):
        def visit_ImportFrom(self, node: ast.ImportFrom) -> None:
            nonlocal text_from_typing

            if node.module != "typing":
                return

            if any(cls.name == "Text" for cls in node.names):
                text_from_typing = True
            else:
                return

            new_import_list = [cls for cls in node.names if cls.name != "Text"]

            ### DEALING WITH EXISTING IMPORT STATEMENTS ###

            # Scenario (1): Now we don't need *any* imports from typing any more.
            if not new_import_list:
                imports_to_delete[node.lineno - 1] = DeleteableImport(old=ast.unparse(node), replacement="")

            # Scenario (2): we still need imports from typing; the existing import statement is only one line
            elif node.lineno == node.end_lineno:
                imports_to_delete[node.lineno - 1] = DeleteableImport(
                    old=ast.unparse(node),
                    replacement=ast.unparse(ast.ImportFrom(module="typing", names=new_import_list, level=0)),
                )

            # Scenario (3): we still need imports from typing; the existing import statement is multiline.
            else:
                for cls in node.names:
                    if cls.name == "Text":
                        imports_to_delete[cls.lineno - 1] = DeleteableImport(
                            old=f"Text," if cls.asname is None else f"Text as {cls.asname},", replacement=""
                        )

    BadImportFinder().visit(tree)

    if not text_from_typing:
        return

    for lineno, (old_syntax, new_syntax) in imports_to_delete.items():
        lines[lineno] = lines[lineno].replace(old_syntax, new_syntax)

    try:
        new_tree = ast.parse("\n".join(lines))
    except SyntaxError:
        sys.stderr.write(f"Error converting new syntax in {path}")
        FAILURES.append(path)
    else:
        lines_with_bad_syntax = []

        class OldSyntaxFinder(ast.NodeVisitor):
            def visit_Name(self, node: ast.Name) -> None:
                if node.id == "Text":
                    lines_with_bad_syntax.append(node.lineno - 1)
                self.generic_visit(node)

        OldSyntaxFinder().visit(new_tree)

        for lineno in lines_with_bad_syntax:
            lines[lineno] = re.sub(r"\bText\b", "str", lines[lineno])

    with open(path, "w") as f:
        f.write("\n".join(lines) + "\n")


def main() -> None:
    print("STARTING RUN: Will attempt to fix new syntax in the stubs directory...\n\n")
    for path in Path(".").rglob("*.pyi"):
        if not any(
            str(path).startswith(stubname) for stubname in {"boto", "cryptography", "paramiko", "pysftp", "pyvmomi", "six"}
        ):
            continue
        print(f"Attempting to convert {path} to new syntax.")
        fix_bad_syntax(path)

    print("\n\nSTARTING ISORT...\n\n")
    subprocess.run([sys.executable, "-m", "isort", "."])

    print("\n\nSTARTING BLACK...\n\n")
    subprocess.run([sys.executable, "-m", "black", "."])

    if FAILURES:
        print("\n\nFAILED to convert the following files to new syntax:\n")
        for path in FAILURES:
            print(f"- {path}")
    else:
        print("\n\nThere were ZERO failures in converting to new syntax. HOORAY!!\n\n")

    print('\n\nRunning "check_new_syntax.py"...\n\n')
    subprocess.run([sys.executable, "../tests/check_new_syntax.py"])


if __name__ == "__main__":
    main()

This PR only modifies the stubs identified as newly Python3-only in #7466 (comment)

[srittau]

Aka AnyStr

[AlexWaygood]

Nice