Encapsulate Windows exec logic in platform.command(exe)

Replace the old base_command() function (which always returned
["cmd.exe", "/c"] on Windows, regardless of whether that was
appropriate) with a new command(exe) function that takes the executable
into account and returns the full invocation list.

This makes the "should I wrap in a shell?" decision live in platform
where it belongs, ensures it can't be called without providing the
executable, and eliminates the footgun that caused the parentheses bug.

As per apposed/appose-java@4849c5a

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

Author: ctrueden

src/appose/tool/__init__.py

@@ -288,17 +288,8 @@ def _do_exec(
         self._captured_output.clear()
         self._captured_error.clear()
 
-        # Build command.
-        # On Windows, cmd.exe /c is needed for shell scripts and PATH resolution,
-        # but absolute paths to native executables must be invoked directly:
-        # cmd.exe treats parentheses and other characters as shell metacharacters,
-        # so a path like C:\Users\foo\Fiji(1)\bin\pixi.exe would be misinterpreted.
-        cmd = (
-            []
-            if platform.is_windows() and Path(self.command).is_absolute()
-            else platform.base_command()
-        )
-        cmd.append(self.command)
+        # Build command
+        cmd = platform.command(self.command)
         if include_flags:
             cmd.extend(self._flags)
         cmd.extend(args)

src/appose/util/platform.py

@@ -124,13 +124,26 @@ def is_executable(file: Path) -> bool:
         return file.exists() and os.access(file, os.X_OK)
 
 
-def base_command() -> list[str]:
+def command(exe: str) -> list[str]:
     """
-    Get the arguments to prefix to execute a command in a separate process.
+    Get the command list needed to invoke the given executable.
+
+    On Windows, absolute paths to native executables are invoked directly
+    via subprocess, bypassing cmd.exe entirely. This is necessary because
+    cmd.exe treats parentheses and other characters as shell metacharacters,
+    which would break paths like C:\\Users\\foo\\Fiji(1)\\bin\\pixi.exe.
+    Relative names (which need shell PATH resolution) still get
+    ['cmd.exe', '/c'] prepended.
+
+    Args:
+        exe: The executable path or name to invoke.
 
     Returns:
-        ['cmd.exe', '/c'] for Windows and an empty list otherwise.
+        A list starting with the executable, preceded by ['cmd.exe', '/c']
+        when needed.
     """
-    if is_windows():
-        return ["cmd.exe", "/c"]
-    return []
+    from pathlib import Path
+
+    if is_windows() and not Path(exe).is_absolute():
+        return ["cmd.exe", "/c", exe]
+    return [exe]