Optional cached imports

docs/functionality.rst

@@ -89,7 +89,10 @@ containing those import statements at ``config.imports``, as a list of
 To get the imported objects, these imports must be resolved, which can be done through
 the :func:`ymmsl.v0_2.resolve` function. This takes the name of the module corresponding
 to a ``Configuration`` (which is the file name without the ``.ymmsl`` extension, wrapped
-in a :class:`ymmsl.v0_2.Reference`) and the configuration itself.
+in a :class:`ymmsl.v0_2.Reference`), the configuration itself, and an optional
+``reuse_cached_imports`` keyword argument. By default, imports are cached between calls to
+avoid re-reading previously loaded modules. Set ``reuse_cached_imports=False`` when the
+search path is changed (``YMMSL_PATH`` or ``sys.path``) to avoid stale module imports.
 
 It updates that configuration in place, renaming any local models and programs to their
 absolute name by prefixing them with the given module name, then imports the

ymmsl/v0_2/resolver.py

@@ -89,7 +89,9 @@ def search_paths(self, rel_path: Path, indent_depth: int) -> str:
         )
 
 
-def resolve(module: Reference, config: Configuration) -> None:
+def resolve(
+    module: Reference, config: Configuration, reuse_cached_imports: bool = True
+) -> None:
     """Resolve imports for the given configuration.
 
     This updates the given configuration in place, removing all import statements and
@@ -100,11 +102,16 @@ def resolve(module: Reference, config: Configuration) -> None:
     Args:
         module: The module corresponding to this configuration
         config: The configuration to resolve
+        reuse_cached_imports: If cached imports should be reused from previous calls of
+            this method. Disable if YMMSL_PATH or sys.path changes.
 
     Raises:
         RuntimeError: if an error occurs due to an invalid configuration. This will
             leave config in a broken state, so reload it if you want to try again.
     """
+    if not reuse_cached_imports:
+        ymmsl_cache.clear()
+
     overwritten = do_resolve(Path("<main>"), module, config, ResolutionContext())
     remove_overwritten_implementations(config, overwritten)