List index out of range with dynamic callback args #382
Description
It seems dash-extensions does not allow dynamic callback args while the "regular" dash does.
Minimal example to reproduce the issue:
from dash import html, dcc
from dash_extensions.enrich import Dash, Output, Input, State, Trigger
app = Dash(__name__)
app.layout = html.Div([
dcc.Input(id='input-1', type='number', value=0, placeholder="Enter first number"),
dcc.Input(id='input-2', type='number', value=0, placeholder="Enter second number"),
html.Button("Calc", id='calc-button', n_clicks=0),
html.Div(id='output', style={'marginTop': '20px', 'fontSize': '20px'})
])
# Dynamically create a list of State dependencies for the two input fields.
input_ids = ['input-1', 'input-2']
states = [State(comp_id, 'value') for comp_id in input_ids]
@app.callback(Output('output', 'children'),
Input('calc-button', 'n_clicks'),
*states
)
def update_output(*values):
try:
total = sum((float(v) if v is not None else 0) for v in values[1:])
except ValueError:
total = "Invalid input"
return f"Sum: {total}"
if __name__ == '__main__':
app.run(debug=True, port=8057, host='0.0.0.0')
When running this I get
Traceback (most recent call last):
File "../py3.9_venv/lib/python3.9/site-packages/dash_extensions/enrich.py", line 1055, in decorated_function
an = full_arg_spec.annotations.get(full_arg_spec.args[i])
IndexError: list index out of range
When importing Dash from dash instead of from dash_extensions.enrich, the app runs fine.
The issue seems to be that inspect.getfullargspec() sees an empty list of args when the arguments are defined as *args, as update_output does.
I'm on python 3.9 and dash-extensions 1.0.11, but from looking at the dash-extensions code, the issue is present in later versions as well.