Streamlit Plotly Chart: content Width Causes Deprecation Warning

It seems like a small hiccup has appeared in the world of Streamlit and Plotly integration. Specifically, when you try to get your Plotly charts to be dynamically sized using the width="content" argument in st.plotly_chart, you might be seeing a deprecation warning pop up. This is a bit confusing, especially when you're not actually using any variable keyword arguments (kwargs) yourself, but sticking to the documented parameters. Let's dive into what's happening and why this might be a bit of a head-scratcher for developers.

Understanding the st.plotly_chart Function and Keyword Arguments

Streamlit's st.plotly_chart is a fantastic tool for embedding interactive Plotly visualizations directly into your Streamlit applications. It makes data visualization a breeze. Like many Python functions, st.plotly_chart accepts various arguments to control how the chart is displayed. Some of these are direct parameters (like fig for the figure object itself, or use_container_width which has now been largely superseded by width and height), while others can be passed as keyword arguments (kwargs). These kwargs are often used for more advanced configurations or settings that aren't explicitly defined as separate parameters in the function's signature.

Recently, there have been updates in Streamlit aimed at refining how keyword arguments are handled, particularly to make the API cleaner and more predictable. Part of this effort involved deprecating the direct use of arbitrary kwargs for certain configurations, encouraging developers to use a dedicated config argument instead. This is generally a good thing, as it prevents potential naming conflicts and makes it clearer where specific settings should go. However, in this particular case, the deprecation warning seems to be triggered even when a user is not passing arbitrary kwargs, but is instead using a documented parameter like width="content".

This is where the confusion arises. The warning suggests that kwargs are being used in a deprecated way, but the user is simply trying to leverage a standard, documented feature for responsive chart sizing. It's like getting a warning about using a specific tool incorrectly when you're just following the instructions in the manual. This can lead to a moment of pause, making developers wonder if they're missing something or if there's a bug in the library itself. The goal of clear API design is to avoid such ambiguities, and this situation, while likely a minor bug or oversight, can disrupt that.

To put it simply, the st.plotly_chart function is designed to be flexible, and allowing charts to adapt to the available width (width="content") is a really useful feature for creating responsive dashboards. When a deprecation warning pops up unexpectedly for this functionality, it creates a user experience friction. Developers might start questioning their code, spending time debugging an issue that isn't actually in their implementation, but rather in how the library is interpreting their arguments. This is precisely the kind of scenario that a well-managed dependency update aims to prevent. Understanding this nuance is key to appreciating why this specific issue, while seemingly small, warrants attention from the Streamlit team.

The Specific Issue: `width=