gh-121790: Fix interactive console initialization (#121793)

Co-authored-by: Łukasz Langa <lukasz@langa.pl>

Lib/_pyrepl/main.py

@@ -23,7 +23,7 @@ else:
 
 def interactive_console(mainmodule=None, quiet=False, pythonstartup=False):
     if not CAN_USE_PYREPL:
-        if not os.environ.get('PYTHON_BASIC_REPL', None) and FAIL_REASON:
+        if not os.getenv('PYTHON_BASIC_REPL') and FAIL_REASON:
             from .trace import trace
             trace(FAIL_REASON)
             print(FAIL_REASON, file=sys.stderr)
@@ -51,5 +51,7 @@ def interactive_console(mainmodule=None, quiet=False, pythonstartup=False):
     if not hasattr(sys, "ps2"):
         sys.ps2 = "... "
 
+    from .console import InteractiveColoredConsole
     from .simple_interact import run_multiline_interactive_console
-    run_multiline_interactive_console(namespace)
+    console = InteractiveColoredConsole(namespace, filename="<stdin>")
+    run_multiline_interactive_console(console)

Lib/_pyrepl/readline.py

@@ -58,7 +58,7 @@ from .types import Callback, Completer, KeySpec, CommandName
 TYPE_CHECKING = False
 
 if TYPE_CHECKING:
-    from typing import Any
+    from typing import Any, Mapping
 
 
 MoreLinesCallable = Callable[[str], bool]
@@ -559,7 +559,7 @@ for _name, _ret in [
 # ____________________________________________________________
 
 
-def _setup(namespace: dict[str, Any]) -> None:
+def _setup(namespace: Mapping[str, Any]) -> None:
     global raw_input
     if raw_input is not None:
         return  # don't run _setup twice
@@ -575,7 +575,9 @@ def _setup(namespace: dict[str, Any]) -> None:
     _wrapper.f_in = f_in
     _wrapper.f_out = f_out
 
-    # set up namespace in rlcompleter
+    # set up namespace in rlcompleter, which requires it to be a bona fide dict
+    if not isinstance(namespace, dict):
+        namespace = dict(namespace)
     _wrapper.config.readline_completer = RLCompleter(namespace).complete
 
     # this is not really what readline.c does.  Better than nothing I guess

Lib/_pyrepl/simple_interact.py

@@ -27,12 +27,9 @@ from __future__ import annotations
 
 import _sitebuiltins
 import linecache
-import builtins
 import sys
 import code
-from types import ModuleType
 
-from .console import InteractiveColoredConsole
 from .readline import _get_reader, multiline_input
 
 TYPE_CHECKING = False
@@ -82,17 +79,12 @@ REPL_COMMANDS = {
 
 
 def run_multiline_interactive_console(
-    namespace: dict[str, Any],
+    console: code.InteractiveConsole,
+    *,
     future_flags: int = 0,
-    console: code.InteractiveConsole | None = None,
 ) -> None:
     from .readline import _setup
-    _setup(namespace)
-
-    if console is None:
-        console = InteractiveColoredConsole(
-            namespace, filename="<stdin>"
-        )
+    _setup(console.locals)
     if future_flags:
         console.compile.compiler.flags |= future_flags