Client.get doesn't evaluate dependency if it's in dictionary value or nested inside dictionary #9186

Describe the issue:

When node is referenced in DAG not in top level list or tuple it's not evaluated when computing graph.

Minimal Complete Verifiable Example:

from dask.core import get_deps
from dask.distributed import Client
import operator

dag = { 
    "a": 3,
    "b": 4,
    "c": (operator.add,"a","b"),
    "d": {"arg1": "c"},
    "e": ["a", "c"],
    "f": { "inner_list": ["a", "c"] },
}
dask_client = Client()
print("Compute graph:")
print(dask_client.get(dag, ["d", "e", "f"]))
print("Dependencies:")
print(get_deps(dag)[0])

Anything else we need to know?:

Output when running the code above:

Compute graph:
[{'arg1': 'c'}, [3, 7], {'inner_list': ['a', 'c']}]
Dependencies:
{'a': set(), 'b': set(), 'c': {'a', 'b'}, 'd': {'c'}, 'e': {'a', 'c'}, 'f': {'a', 'c'}}

It's expected that dictionary values are also evaluated, like it's done for dependencies in top level list or tuple when calling get method. All those dependencies are detected by get_deps function, as above.

This can be related to the issue #8959 : this code example has been tested in dask 2024.11.2 and it produced the expected output, all nodes including inner ones were evaluated:

Compute graph:
[{'arg1': 7}, [3, 7], {'inner_list': [3, 7]}]
Dependencies:
{'a': set(), 'b': set(), 'c': {'b', 'a'}, 'd': {'c'}, 'e': {'a', 'c'}, 'f': {'a', 'c'}}

Environment:

• Dask version: 2026.1.1
• Python version: 3.13
• Operating System: Debian 13 (trixie)
• Install method (conda, pip, source): pip