Fixing St.plotly_chart Kwargs Deprecation Warning

Understanding the Deprecation Warning

When you're diving into the world of Streamlit and Plotly to create interactive data visualizations, encountering deprecation warnings can be a bit of a buzzkill. Specifically, the st.plotly_chart kwargs deprecation warning can pop up even when you think you're doing everything right. This warning typically arises when using parameters like width="content" or height in your st.plotly_chart calls. The core issue is that Streamlit is flagging the use of variable keyword arguments (kwargs), suggesting they will be removed in future releases. This can be perplexing because you might not even be explicitly passing any kwargs; you're simply using documented parameters. To address this, let's break down the problem, understand why it's happening, and explore how to fix it, ensuring your Streamlit apps remain warning-free and up-to-date. By understanding the root cause and implementing the recommended solutions, you can keep your visualizations running smoothly and avoid potential issues down the road.

When integrating Plotly charts into Streamlit applications, developers sometimes encounter a deprecation warning related to kwargs when using st.plotly_chart. This warning can be particularly puzzling because it appears even when no explicit variable keyword arguments are being passed. Instead, developers are simply utilizing documented parameters such as width="content" or height. To effectively tackle this issue, it's important to understand the underlying reasons for the warning and how to properly address it. The deprecation warning indicates that the use of variable keyword arguments in st.plotly_chart is slated for removal in future releases, with a recommendation to use the config argument instead for specifying Plotly configuration options. Therefore, identifying the scenarios in which this warning arises and implementing alternative approaches is crucial for maintaining code compatibility and ensuring smooth operation of Streamlit applications. Furthermore, understanding the proper usage of the config argument allows developers to retain full control over the appearance and behavior of their Plotly charts within Streamlit, while adhering to best practices and avoiding deprecated features. By proactively addressing this deprecation warning, developers can future-proof their code and ensure a seamless transition to newer versions of Streamlit.

Reproducible Code Example

To illustrate the issue, consider the following code snippet:

import plotly.graph_objects as go
import streamlit as st

fig = go.Figure()
fig.add_trace(go.Barpolar(r=[1], theta=[0], width=[120]))
fig.update_layout(width=500, height=360)

st.plotly_chart(fig, width="content")

In this example, we're creating a simple polar bar chart using Plotly and displaying it in a Streamlit app. We set the width to "content" to make the chart responsive. However, running this code will trigger the deprecation warning. The question is, why? We're not passing any arbitrary kwargs, so what's going on? The key is that Streamlit's internal handling of the width and height parameters is triggering the warning because it internally uses kwargs in a way that's now considered deprecated. This means even using officially supported parameters can inadvertently cause this warning to surface. To move forward, we need to find alternative approaches that avoid the use of these deprecated mechanisms while still achieving the desired chart appearance and behavior.

This code snippet demonstrates a common scenario where a deprecation warning arises despite using standard parameters. The warning suggests that variable keyword arguments for st.plotly_chart are deprecated and will be removed in a future release, advising the use of the config argument instead. This situation highlights the need for a deeper understanding of how Streamlit handles these parameters internally and how to adapt code to comply with the recommended practices. By examining the code, it becomes evident that the issue is not with the Plotly figure itself, but rather with how Streamlit processes the width parameter. This implies that the solution lies in either modifying the Streamlit code to avoid the deprecated usage of kwargs or finding an alternative way to specify the chart's width that does not trigger the warning. Ultimately, the goal is to ensure that the Plotly chart is displayed correctly within the Streamlit application while adhering to the latest Streamlit guidelines and avoiding deprecated features. This requires careful consideration of the available options and a thorough understanding of the underlying mechanisms at play.

Steps To Reproduce

Unfortunately, the original issue didn't provide specific steps to reproduce, but the code example is sufficient. Just run the code, and you'll see the warning in your Streamlit app. The warning message will appear in your console or terminal, indicating the deprecation of variable keyword arguments. To ensure the warning is triggered, make sure you're using a Streamlit version that includes the deprecation check. The Streamlit team introduced this warning to encourage developers to adopt more robust and future-proof methods for configuring Plotly charts. Therefore, keeping your Streamlit environment up-to-date will help you identify and address these issues promptly. By consistently testing your code with the latest Streamlit versions, you can proactively identify potential compatibility issues and ensure a smooth transition to newer releases. This proactive approach will save you time and effort in the long run, as you'll be able to address deprecation warnings and other issues before they become major roadblocks in your development process. Furthermore, it allows you to stay informed about the latest best practices and recommendations from the Streamlit team, ensuring that your applications are built on a solid foundation.

Expected Behavior

Ideally, using the width argument as documented should not trigger a deprecation warning. The expectation is that Streamlit should handle this parameter internally without relying on deprecated kwargs mechanisms. When developers follow the official documentation and utilize the recommended parameters, they anticipate a seamless experience without encountering unexpected warnings. The presence of the deprecation warning undermines this expectation and suggests a discrepancy between the documented usage and the actual implementation. This can lead to confusion and frustration among developers, especially those who are new to Streamlit. Therefore, it's crucial for Streamlit to provide clear guidance and consistent behavior, ensuring that the documented parameters function as intended and do not inadvertently trigger deprecation warnings. By aligning the actual implementation with the documented usage, Streamlit can enhance the developer experience and foster greater confidence in the platform.

The correct behavior would involve Streamlit recognizing the width parameter as a valid, non-deprecated argument and processing it accordingly. This would entail either updating the internal implementation to avoid the use of deprecated kwargs or providing a separate mechanism for handling the width parameter that does not trigger the warning. The ultimate goal is to ensure that developers can confidently use the documented parameters without encountering unexpected side effects or being forced to resort to workarounds. This requires a careful review of the Streamlit codebase and a commitment to providing a consistent and reliable API for interacting with Plotly charts. By addressing this issue, Streamlit can demonstrate its dedication to developer satisfaction and maintain its reputation as a user-friendly and robust platform for building data-driven applications.

Current Behavior

Currently, even when using the width parameter as intended (e.g., st.plotly_chart(fig, width="content")), the deprecation warning is triggered. This is due to the following code snippet in Streamlit's implementation:

if kwargs:
    show_deprecation_warning(
        "Variable keyword arguments for st.plotly_chart have been "
        "deprecated and will be removed in a future release. Use the "
        "config argument instead to specify Plotly configuration "
        "options."
    )

This code checks for any kwargs passed to st.plotly_chart. Since Streamlit internally uses kwargs to handle the width parameter, the warning is inevitably displayed, even if you're only using documented parameters. This behavior is not ideal and creates unnecessary noise for developers who are following best practices. The presence of this warning can also mask other, more important warnings, making it harder to identify and address genuine issues in your code. Therefore, it's essential for Streamlit to refine its handling of the width parameter to avoid triggering the deprecation warning when it's used correctly.

This snippet reveals that the deprecation warning is triggered indiscriminately whenever any keyword arguments are passed to st.plotly_chart. This means that even using officially supported parameters like width can inadvertently cause the warning to appear, which is misleading and confusing for developers. The underlying issue is that Streamlit's internal implementation relies on kwargs to handle these parameters, even though the intention is to deprecate the use of variable keyword arguments. This creates a conflict between the documented usage and the actual implementation, leading to the unexpected warning. To resolve this, Streamlit needs to either modify its internal code to avoid using kwargs for these parameters or provide a separate mechanism for handling them that does not trigger the deprecation check. The ultimate goal is to ensure that developers can confidently use the documented parameters without encountering unnecessary warnings or being forced to resort to workarounds.

Is this a regression?

Yes, this is likely a regression. The issue indicates that this used to work in a previous version, meaning that the deprecation warning wasn't triggered when using the width parameter. This suggests that a change in Streamlit's internal implementation introduced this behavior. Regressions can be particularly frustrating for developers because they break existing code that was previously working as expected. Therefore, it's important for Streamlit to carefully review any changes to its internal implementation to avoid introducing regressions that can impact the developer experience. When regressions are identified, it's crucial to address them promptly and provide clear communication to the community about the issue and the steps being taken to resolve it. This helps maintain trust and confidence in the platform and ensures that developers can continue to rely on Streamlit for building their data-driven applications.

Debug Info

• Streamlit version: 1.50.0
• Python version: Python 3.14.2
• Operating System: MacOs 26.1
• Browser: Chrome

This information is helpful for the Streamlit team to diagnose the issue and identify any potential compatibility problems with specific versions or environments. Providing detailed debug information can significantly expedite the troubleshooting process and help the team pinpoint the root cause of the problem. When reporting issues, it's always a good practice to include as much relevant information as possible, such as the Streamlit version, Python version, operating system, browser, and any other relevant dependencies or configurations. This will help the team reproduce the issue and develop a fix more efficiently. Additionally, if you can provide a minimal reproducible example that demonstrates the issue, it will further assist the team in understanding the problem and finding a solution.

Additional Information

No additional information was provided.

Addressing the Deprecation Warning

While a proper fix would require changes to Streamlit itself, here are a few workarounds you can use in the meantime:

1. Ignore the warning: If the chart is displaying correctly, you can choose to ignore the warning for now. However, this is not recommended as the kwargs functionality will eventually be removed.
2. Contribute to Streamlit: The best solution is to contribute to Streamlit by creating a pull request addressing the kwargs issue. Contributing to open-source projects helps the community and can provide you with recognition.

In conclusion, the st.plotly_chart kwargs deprecation warning is a real issue that needs to be addressed. Hopefully, this explanation clarifies the problem and provides some temporary solutions until a proper fix is implemented in Streamlit.