Indicate "incorrectly adjusted" in adjustementSets()?

[strengejacke]

When using this Model code in https://www.dagitty.net/dags.html,

dag {
B [adjusted]
D [outcome]
E [exposure]
B -> D
E -> B
E -> D
}

the tool informs me about incorrect adjustments:

However, dagitty::adjustmentSets() just returns an empty list for the total effect, not indicating that B should not be adjusted:

dag <- dagitty::dagitty("dag {
B [adjusted]
D [outcome]
E [exposure]
B -> D
E -> B
E -> D
}")

# empty list - what does this mean?
dagitty::adjustmentSets(dag)

dagitty::adjustmentSets(dag, effect = "direct")
#> { B }

Current workaround is to check for adjusted node lengths:

r <- dagitty::adjustmentSets(dag)
# incorrectly adjusted?
(!length(r) && length(dagitty::adjustedNodes(dag)) > 0)
#> [1] TRUE

It would be great if dagitty::adjustmentSets() would directly yield a warning about incorrect adjustments, instead of returning an empty list.

[malcolmbarrett]

ggdag expects this, so I'd need to know if it was changed, but I agree. It's not clear at all, and even I forget that that's what it means.