Function build_async_tree

Lib/asyncio/tools.py:148–176

Build a list of strings for pretty-print an async call tree. The call tree is produced by `get_all_async_stacks()`, prefixing tasks with `task_emoji` and coroutine frames with `cor_emoji`.

(result, task_emoji="(T)", cor_emoji="")

def build_async_tree(result, task_emoji="(T)", cor_emoji=""):
    """
    Build a list of strings for pretty-print an async call tree.

    The call tree is produced by `get_all_async_stacks()`, prefixing tasks
    with `task_emoji` and coroutine frames with `cor_emoji`.
    """
    id2name, awaits, task_stacks = _index(result)
    g = _task_graph(awaits)
    cycles = _find_cycles(g)
    if cycles:
        raise CycleFoundException(cycles, id2name)
    labels, children = _build_tree(id2name, awaits, task_stacks)

    def pretty(node):
        flag = task_emoji if node[0] == NodeType.TASK else cor_emoji
        return f"{flag} {labels[node]}"

    def render(node, prefix="", last=True, buf=None):
        if buf is None:
            buf = []
        buf.append(f"{prefix}{'└── ' if last else '├── '}{pretty(node)}")
        new_pref = prefix + ("    " if last else "│   ")
        kids = children.get(node, [])
        for i, kid in enumerate(kids):
            render(kid, new_pref, i == len(kids) - 1, buf)
        return buf

    return [render(root) for root in _roots(labels, children)]


def build_task_table(result):