fix(resolve_exe): allow shutil.which() to find exe without suffix in Windows

autotest/test_mbase.py

@@ -135,10 +135,8 @@ def test_run_model_exe_rel_path(mf6_model_path, function_tmpdir, use_ext):
 
     bin_dir = function_tmpdir / "bin"
     bin_dir.mkdir()
-    inner_dir = function_tmpdir / "inner"
-    inner_dir.mkdir()
 
-    with set_dir(inner_dir):
+    with set_dir(ws):
         # copy exe to relative dir
         copy(mf6, bin_dir / "mf6")
         assert (bin_dir / "mf6").is_file()

flopy/mbase.py

@@ -64,31 +64,31 @@ def resolve_exe(exe_name: Union[str, os.PathLike], forgive: bool = False) -> str
         str: absolute path to the executable
     """
 
-    def _resolve(exe_name):
-        exe = which(exe_name)
-        if exe is not None:
-            # if which() returned a relative path, resolve it
-            exe = which(str(Path(exe).resolve()))
-        else:
-            if exe_name.lower().endswith(".exe"):
-                # try removing .exe suffix
-                exe = which(exe_name[:-4])
-            if exe is not None:
-                # in case which() returned a relative path, resolve it
-                exe = which(str(Path(exe).resolve()))
-            else:
-                # try tilde-expanded abspath
-                exe = which(Path(exe_name).expanduser().absolute())
-            if exe is None and exe_name.lower().endswith(".exe"):
-                # try tilde-expanded abspath without .exe suffix
-                exe = which(Path(exe_name[:-4]).expanduser().absolute())
-        return exe
-
-    name = str(exe_name)
-    exe_path = _resolve(name)
-    if exe_path is None and on_windows and Path(name).suffix == "":
-        # try adding .exe suffix on windows (for portability from other OS)
-        exe_path = _resolve(f"{name}.exe")
+    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(str(exe_name)):
+            return which(str(Path(exe).resolve()))
+
+        # exe_name is relative path
+        if not Path(exe_name).is_absolute() and (
+            exe := which(str(Path(exe_name).expanduser().resolve()), mode=0)
+        ):
+            # expanduser() in case of ~ in path
+            # mode=0 effectively allows which() to find exe without suffix in windows
+            return exe
+
+        # try adding/removing .exe suffix
+        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", checked)
+
+    exe_path = _resolve(exe_name)
 
     # raise if we are unforgiving, otherwise return None
     if exe_path is None:
@@ -103,7 +103,7 @@ def _resolve(exe_name):
             f"The program {exe_name} does not exist or is not executable."
         )
 
-    return exe_path
+    return str(exe_path)
 
 
 # external exceptions for users