ExecContext: Make mode:xxx an enum

This commit introduces two new types, Input and InputMode. They
replace the more error-prone special strings cmd_input could be used
with. InputMode is an Enum, and Input can be either IntputMode, a
string or None.

Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/lib/ExecContext.py

@@ -3,7 +3,8 @@
 from __future__ import annotations
 
 import abc, re, sys
-from typing import NamedTuple, TYPE_CHECKING
+from enum import Enum, auto
+from typing import NamedTuple, TypeAlias, TYPE_CHECKING
 
 if TYPE_CHECKING:
     from typing import Self, Type
@@ -12,6 +13,14 @@ if TYPE_CHECKING:
 from .log import *
 from .util import pretty_cmd
 
+class InputMode(Enum):
+    Interactive = auto()
+    NonInteractive = auto()
+    OptInteractive = auto()
+    Auto = auto()
+
+Input: TypeAlias = InputMode | None | str
+
 class Result(NamedTuple):
 
     stdout: str|None
@@ -34,7 +43,7 @@ class ExecContext(abc.ABC):
                 parent: ExecContext,
                 title: str,
                 cmd: list[str],
-                cmd_input: str|None,
+                cmd_input: Input,
                 wd: str|None,
                 log_prefix: str,
                 throw: bool,
@@ -53,13 +62,13 @@ class ExecContext(abc.ABC):
             # or False
             interactive: bool|None = None
             match cmd_input:
-                case 'mode:interactive':
+                case InputMode.Interactive:
                     interactive = True
-                case 'mode:non-interactive':
+                case InputMode.NonInteractive:
                     interactive = False
-                case 'mode:opt-interactive':
+                case InputMode.OptInteractive:
                     interactive = parent.interactive
-                case 'mode:auto':
+                case InputMode.Auto:
                     interactive = sys.stdin.isatty()
             if interactive is None:
                 interactive = parent.interactive
@@ -68,7 +77,7 @@ class ExecContext(abc.ABC):
             assert interactive in [ True, False ]
             self.__interactive = interactive
 
-            self.__cmd_input = cmd_input if cmd_input[:5] != 'mode:' else None
+            self.__cmd_input = cmd_input if not isinstance(cmd_input, InputMode) else None
             self.__throw = throw
             self.__verbose = verbose if verbose is not None else parent.verbose_default
             self.__pretty_cmd: str|None = None
@@ -97,6 +106,10 @@ class ExecContext(abc.ABC):
         def verbose(self) -> bool:
             return self.__verbose
 
+        @property
+        def cmd_input(self) -> bool:
+            return self.__cmd_input
+
         @property
         def pretty_cmd(self) -> str:
             if self.__pretty_cmd is None:
@@ -159,7 +172,7 @@ class ExecContext(abc.ABC):
         wd: str|None = None,
         throw: bool = True,
         verbose: bool|None = None,
-        cmd_input: str|None = 'mode:opt-interactive',
+        cmd_input: Input = InputMode.OptInteractive,
         env: dict[str, str]|None = None,
         title: str=None
     ) -> Result:
@@ -172,11 +185,11 @@ class ExecContext(abc.ABC):
             throw:   Raise an exception on non-zero exit status if True
             verbose: Emit log output while the command runs
             cmd_input:
-                - "mode:opt-interactive"  -> Let --interactive govern how to handle interactivity (default)
-                - "mode:interactive"      -> Inherit terminal stdin
-                - "mode:auto"             -> Inherit terminal stdin if it is a TTY
-                - "mode:non-interactive"  -> stdin from /dev/null
-                - None                    -> Alias for mode:non-interactive
+                - "InputMode.OptInteractive"  -> Let --interactive govern how to handle interactivity (default)
+                - "InputMode.Interactive"     -> Inherit terminal stdin
+                - "InputMode.Auto"            -> Inherit terminal stdin if it is a TTY
+                - "InputMode.NonInteractive"  -> stdin from /dev/null
+                - None                        -> Alias for InputMode.NonInteractive
                 - otherwise                   -> Feed cmd_input to stdin
             env:     The environment the command should be run in
 
@@ -193,7 +206,7 @@ class ExecContext(abc.ABC):
                     cmd=cmd,
                     wd=wd,
                     verbose=cc.verbose,
-                    cmd_input=cmd_input,
+                    cmd_input=cc.cmd_input,
                     env=env,
                     interactive=cc.interactive,
                     log_prefix = cc.log_prefix
@@ -230,7 +243,7 @@ class ExecContext(abc.ABC):
                     opts=opts,
                     wd=wd,
                     verbose=cc.verbose,
-                    cmd_input=cmd_input,
+                    cmd_input=cc.cmd_input,
                     env=env,
                     interactive=cc.interactive,
                     log_prefix = cc.log_prefix,