Streamlit Plotly Chart Kwargs Warning: A Fix Guide

Welcome, fellow data enthusiasts and app builders! If you've been working with Streamlit, you know the sheer delight of bringing your data to life with interactive visualizations. Among the many powerful tools at your disposal, Plotly charts stand out for their beauty and interactivity, making your Streamlit apps truly shine. However, like any evolving technology, you might occasionally bump into a warning message that leaves you scratching your head. One such message that has recently appeared for many developers is the plotly_chart kwargs deprecation warning when using st.plotly_chart, especially when you're just trying to set a simple parameter like width="content". It's a bit like buying a new gadget and getting an unexpected message telling you not to use one of its advertised features!

This article is your friendly guide through this particular maze. We're going to dive deep into what this st.plotly_chart kwargs deprecation warning actually means, why it's appearing even for seemingly valid parameters like width="content", and most importantly, how you can resolve it to keep your Streamlit applications running smoothly and warning-free. We'll break down the technical jargon into easy-to-understand explanations, provide clear examples, and offer strategies to not only fix the immediate issue but also future-proof your data visualization code. Whether you're a seasoned Streamlit developer or just starting your journey, understanding these nuances is crucial for building robust and maintainable applications. We’ll explore how Streamlit's API is evolving, particularly concerning how it handles underlying Plotly configurations, and equip you with the knowledge to navigate these changes confidently. So, let's get ready to banish those deprecation warnings and continue building amazing interactive data dashboards without a hitch!

Understanding the Plotly Chart Kwargs Deprecation Warning

What's Happening Under the Hood?

So, you're using st.plotly_chart with parameters you know are documented, like width="content", and suddenly, a kwargs deprecation warning pops up. It's confusing, right? Let's unpack what's really going on here. In Python, **kwargs is a powerful construct that allows functions to accept an arbitrary number of keyword arguments. It's super flexible, but it can also make an API less explicit if not managed carefully. Historically, st.plotly_chart was quite flexible, allowing users to pass many Plotly-specific configuration options directly as kwargs alongside its own parameters. This flexibility was convenient but could sometimes lead to ambiguity or make it harder for Streamlit to manage and evolve its own API, especially when underlying libraries like Plotly introduced their own breaking changes or new features.

Recently, the Streamlit team decided to make the API for st.plotly_chart more explicit and robust. This involved a change (specifically highlighted in related issues and pull requests, such as the one implicitly referenced in the original bug report) to deprecate the direct passing of arbitrary kwargs for Plotly configuration. The intent was clear: to encourage users to pass Plotly configuration options through a dedicated config dictionary, making the separation of concerns clearer. Streamlit's own parameters, like width and height, should ideally be handled directly by Streamlit, while Plotly-specific configurations, such as controlling the display mode bar or enabling scroll zoom, should go into the config argument. The problem arises because the deprecation check, introduced in Streamlit versions around 1.50.0 (as indicated by the debug info), seems to be a bit overly eager. It flags `width=