plotly / plotly/dash

Non-rendered components with side-effects can cause unexpected values in callbacks

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bug P3
Dominant language
Python
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Description

DataTable and dcc.Graph both cause side-effects when rendered.

The dcc.Graph evaluates extendData into the figure and the table calculates the value of derived_** props. If one of these is in the layout but not rendered (e.g. unfocused tab), these side-effects do not occur, causing the value of props to be different from expected.

Not sure what/how we'll want to fix this but starting off by documenting the behavior/limitation of the system.

This limitation was found as part of work on #1010.

Contributor guide

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Review the documented behavior of DataTable and dcc.Graph, especially dcc.Graph's extendData and the table's derived_** props, then read the related work in issue #1010. Document that components in the layout may not apply these side effects when they are not rendered, such as in an unfocused tab, and make the resulting callback-value limitation clear.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
documentation, frontend
Issue type
Documentation
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
35/100

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