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setCallbackContext error occurs in pattern-matching callbacks with one or more input IDs as strings #236
Description
In translating a Python demo app for pattern-matching callbacks with the following signature
app$callback(
output(id = list("index" = MATCH, "type" = "dynamic-output"), property = "figure"),
params = list(
input(id = list("index" = MATCH, "type" = "dynamic-dropdown-x"), property = "value"),
input(id = list("index" = MATCH, "type" = "dynamic-dropdown-y"), property = "value"),
input(id = "country", property = "value")I encountered the error:
values must be length 1,
but FUN(X[[1]]) result is length 2I was able to trace this error to setCallbackContext, and the following statement:
Line 1065 in add8dd3
I suspect that the issue is that we convert the IDs to JSON-like syntax later in the function, and so the length of the IDs is not uniformly 1:
> input_id
[1] "country"
> callback_elements$inputs
[[1]]
[[1]]$id
[[1]]$id$index
[1] 0
[[1]]$id$type
[1] "dynamic-dropdown-x"
[[1]]$property
[1] "value"
[[1]]$value
[1] "year"
[[2]]
[[2]]$id
[[2]]$id$index
[1] 0
[[2]]$id$type
[1] "dynamic-dropdown-y"
[[2]]$property
[1] "value"
[[2]]$value
[1] "gdpPercap"
[[3]]
[[3]]$id
[1] "country"
[[3]]$property
[1] "value"
[[3]]$value
[1] "Bulgaria"One option is to unlist the IDs when matching on their value. Alternatively, we could consider whether the ordering of the if/else logic within setCallbackContext is ultimately what we want.
Whatever solution we identify, we should ensure that a heterogeneous mix of IDs that are lists and vectors (i.e. using selectors or not) is allowed when describing callbacks so that this error does not occur.
Activity
rpkyle commentedon Oct 30, 2020
Resolved via #237, closing.