prevent infinite recursion in removing/adding .exe suffix on windows

flopy/mbase.py

@@ -64,7 +64,12 @@ def resolve_exe(exe_name: Union[str, os.PathLike], forgive: bool = False) -> str
         str: absolute path to the executable
     """
 
-    def _resolve(exe_name):
+    def _resolve(exe_name, checked=set()):
+        # Prevent infinite recursion by checking if exe_name has been checked
+        if exe_name in checked:
+            return None
+        checked.add(exe_name)
+
         # exe_name is found (not None), ensure absolute path is returned
         if exe := which(exe_name):
             return which(Path(exe).resolve())
@@ -80,10 +85,10 @@ def _resolve(exe_name):
             return exe
 
         # try adding/removing .exe suffix
-        if on_windows and exe_name.lower().endswith(".exe"):
-            return _resolve(exe_name[:-4])
+        if exe_name.lower().endswith(".exe"):
+            return _resolve(exe_name[:-4], checked)
         elif on_windows and "." not in Path(exe_name).stem:
-            return _resolve(f"{exe_name}.exe")
+            return _resolve(f"{exe_name}.exe", checked)
 
     exe_path = _resolve(exe_name)