Removed unnecessary checks for the validity of callbacks

Author: waralex

src/app/callbacks.jl

@@ -165,21 +165,11 @@ function check_callback(func, app::DashApp, deps::CallbackDeps)
     isempty(deps.output) && error("The callback method requires that one or more properly formatted outputs are passed.")
     isempty(deps.input) && error("The callback method requires that one or more properly formatted inputs are passed.")
 
-    !check_unique(deps.output) && error("One or more callback outputs have been duplicated; please confirm that all outputs are unique.")
-
-    for out in deps.output
-        if any(x->out in x.dependencies.output, values(app.callbacks))
-            error("output \"$(out)\" already registered")
-        end
-    end
 
     args_count = length(deps.state) + length(deps.input)
 
     check_callback_func(func, args_count)
 
-    for id_prop in deps.input
-        id_prop in deps.output && error("Circular input and output arguments were found. Please verify that callback outputs are not also input arguments.")
-    end
 end
 
 function check_callback_func(func::Function, args_count)

src/handler/callback_context.jl

@@ -1,34 +1,50 @@
 using .Contexts
 const CallbackContextItems = Union{Nothing, Vector{NamedTuple}}
 const TriggeredParam = NamedTuple{(:prop_id, :value)}
+
+struct FakeTriggeredParams <: AbstractVector{TriggeredParam}
+end
+Base.size(v::FakeTriggeredParams) = (1,)
+Base.isempty(v::FakeTriggeredParams) = true
+Base.IndexStyle(::Type{FakeTriggeredParams}) = IndexLinear()
+Base.length(v::FakeTriggeredParams) = 1
+function Base.getindex(v::FakeTriggeredParams, i::Int)
+    i != 1 && throw(BoundsError(v, i))
+    return (prop_id = ".", value = nothing)
+end
+
 mutable struct CallbackContext
     response::HTTP.Response
     inputs::Dict{String, Any}
     states::Dict{String, Any}
     outputs_list::Vector{Any}
     inputs_list::Vector{Any}
     states_list::Vector{Any}
-    triggered::Vector{TriggeredParam}
+    triggered::Union{Vector{TriggeredParam}, FakeTriggeredParams}
     function CallbackContext(response, outputs_list, inputs_list, states_list, changed_props)
         input_values = inputs_list_to_dict(inputs_list)
         state_values = inputs_list_to_dict(states_list)
-        triggered = TriggeredParam[(prop_id = id, value = input_values[id]) for id in changed_props]
+        if !isempty(changed_props)
+            triggered = TriggeredParam[(prop_id = id, value = input_values[id]) for id in changed_props]
+        else
+            triggered = FakeTriggeredParams()
+        end
         return new(response, input_values, state_values, outputs_list, inputs_list, states_list, triggered)
     end
 end
 
 const _callback_context_storage = TaskContextStorage()
 
-function with_callback_context(f, context::CallbackContext) 
+function with_callback_context(f, context::CallbackContext)
     return with_context(f, _callback_context_storage, context)
-end 
+end
 
 """
     callback_context()::CallbackContext
 
     Get context of current callback, available only inside callback processing function
 """
-function callback_context() 
+function callback_context()
     !has_context(_callback_context_storage) && error("callback_context() is only available from a callback processing function")
     return get_context(_callback_context_storage)
 end

test/callbacks.jl

@@ -260,32 +260,6 @@ end
     @test app.callbacks[Symbol("my-div.children")].func("value") == "value"
     @test app.callbacks[Symbol("my-div2.children")].func("value") == "v_value"
 
-    #output already exists
-    @test_throws ErrorException callback!(app, Output("my-div2","children"), Input("my-id","value")) do value
-        return "v_$(value)"
-    end
-
-    #output same as input
-    @test_throws ErrorException callback!(app,
-        Output("my-id","value"),
-        Input("my-id","value"),
-        State("my-id","value")) do value
-        return "v_$(value)"
-    end
-
-    #output same as input
-    @test_throws ErrorException callback!(app,
-        Output("my-id","value"),
-        [Input("my-id","value"), Input("my-div","children")]) do value
-        return "v_$(value)"
-    end
-
-    #output same as input
-    @test_throws ErrorException callback!(app,
-        [Output("my-id","value"), Output("my-div","children")],
-        Input("my-id","value")) do value
-        return "v_$(value)"
-    end
 
     #empty input
     @test_throws ErrorException callback!(app,
@@ -295,13 +269,6 @@ end
     end
 
 
-    #duplicated output
-    @test_throws ErrorException callback!(app,
-        [Output("my-div","value"), Output("my-div","value")],
-        Input("my-id","value")) do value
-        return "v_$(value)"
-    end
-
     app = dash()
 
     app.layout = html_div() do
@@ -339,6 +306,38 @@ end
 
 end
 
+@testset "fake triggered params" begin
+    app = dash()
+    app.layout = html_div() do
+            dcc_input(id = "test-in", value="initial value", type = "text"),
+            html_div(id = "test-out")
+        end
+
+    callback!(app, Output("test-out", "children"), Input("test-out", "value")) do value
+        context = callback_context()
+        @test length(context.triggered) == 1
+        @test context.triggered[1].prop_id == "."
+        @test isnothing(context.triggered[1].value)
+        @test isempty(context.triggered)
+        return string(value)
+    end
+    @test length(app.callbacks) == 1
+
+    handler = Dash.make_handler(app)
+    request = (
+        output = "test-out.children",
+        changedPropIds = [],
+        inputs = [
+            (id = "test-in", property = "value", value = "test")
+        ]
+    )
+    test_json = JSON2.write(request)
+    request = HTTP.Request("POST", "/_dash-update-component", [], Vector{UInt8}(test_json))
+    response = HTTP.handle(handler, request)
+
+    @test response.status == 200
+
+end
 @testset "pattern-match" begin
     app = dash()
     app.layout = html_div() do

test/integration/callbacks/jl_test_wildcards/jlcbwc004_layout_chunk_changed_props.jl

@@ -24,8 +24,14 @@ end
 
 function trigger_info()
     triggered = callback_context().triggered
-    trig_string = !isempty(triggered) ? "Truthy" : "Falsy"
-    prop_ids = join(getproperty.(triggered, :prop_id), ", ")
+    trig_string = ""
+    prop_ids = ""
+    if isempty(triggered)
+        trig_string =  "Falsy"
+    else
+        trig_string = "Truthy"
+        prop_ids = join(getproperty.(triggered, :prop_id), ", ")
+    end
     return "triggered is $trig_string with prop_ids $prop_ids"
 end
 

test/integration/callbacks/test_wildcards.py

@@ -174,7 +174,7 @@ def test_jlcbwc004_layout_chunk_changed_props(dashjl):
 
     dashjl.wait_for_text_to_equal("#container", "No content initially", timeout = 10)
     dashjl.wait_for_text_to_equal(
-        "#output-outer", "triggered is Falsy with prop_ids", timeout = 10
+        "#output-outer", "triggered is Falsy with prop_ids", timeout = 30
     )
 
     dashjl.find_element("#btn").click()