Function load_graph

mypy/build.py:4254–4426

Given some source files, load the full dependency graph. If an old_graph is passed in, it is used as the starting point and modified during graph loading. If a new_modules is passed in, any modules that are loaded are added to the list. This is an argument and not a return value

(
    sources: list[BuildSource],
    manager: BuildManager,
    old_graph: Graph | None = None,
    new_modules: list[State] | None = None,
)

def load_graph(
    sources: list[BuildSource],
    manager: BuildManager,
    old_graph: Graph | None = None,
    new_modules: list[State] | None = None,
) -> Graph:
    """Given some source files, load the full dependency graph.

    If an old_graph is passed in, it is used as the starting point and
    modified during graph loading.

    If a new_modules is passed in, any modules that are loaded are
    added to the list. This is an argument and not a return value
    so that the caller can access it even if load_graph fails.

    As this may need to parse files, this can raise CompileError in case
    there are syntax errors.
    """

    graph: Graph = old_graph if old_graph is not None else {}

    # The deque is used to implement breadth-first traversal.
    # TODO: Consider whether to go depth-first instead.  This may
    # affect the order in which we process files within import cycles.
    new = new_modules if new_modules is not None else []
    entry_points: set[str] = set()
    # Seed the graph with the initial root sources.
    for bs in sources:
        try:
            st = State.new_state(
                id=bs.module,
                path=bs.path,
                source=bs.text,
                manager=manager,
                root_source=not bs.followed,
            )
        except ModuleNotFound:
            continue
        if st.id in graph:
            manager.errors.set_file(st.xpath, st.id, manager.options)
            manager.error(
                None,
                f'Duplicate module named "{st.id}" (also at "{graph[st.id].xpath}")',
                blocker=True,
            )
            resolution_note = f"""
            See {MODULE_RESOLUTION_URL} for more info
            Common resolutions include:
                a) using `--exclude` to avoid checking one of them,
                b) adding `__init__.py` somewhere,
                c) using `--explicit-package-bases` or adjusting `MYPYPATH`
            """
            manager.note_multiline(None, resolution_note)
            manager.errors.raise_error()
        graph[st.id] = st
        new.append(st)
        entry_points.add(bs.module)
    manager.parse_all([state for state in new if state.needs_parse])