Clear stash if system executable is missing (#2050)

Signed-off-by: Bernát Gábor <[email protected]>

docs/changelog/2050.bugfix.rst

@@ -0,0 +1,2 @@
+Drop cached python information if the system executable is no longer present (for example when the executable is a
+shim and the mapped executable is replaced - such is the case with pyenv) - by :user:`gaborbernat`.

src/virtualenv/discovery/cached_py_info.py

@@ -65,6 +65,10 @@ def _get_via_file_cache(cls, app_data, path, exe):
             of_path, of_st_mtime, of_content = data["path"], data["st_mtime"], data["content"]
             if of_path == path_text and of_st_mtime == path_modified:
                 py_info = cls._from_dict({k: v for k, v in of_content.items()})
+                sys_exe = py_info.system_executable
+                if sys_exe is not None and not os.path.exists(sys_exe):
+                    py_info_store.remove()
+                    py_info = None
             else:
                 py_info_store.remove()
         if py_info is None:  # if not loaded run and save