Streamlit Plotly_chart Kwargs Warning Fix
Hey there, Streamlit enthusiasts! Ever found yourself staring at a deprecation warning that seems to pop up out of nowhere? You're not alone! Many users have recently encountered a peculiar warning when using the st.plotly_chart function, specifically when setting the width or height arguments, even when you're diligently following the documentation and not explicitly using variable keyword arguments (kwargs). This can be a bit puzzling, right? Let's dive into what's causing this, why it's happening, and how we can smoothly navigate this change. Understanding the deprecation warning is key to keeping your Streamlit apps running smoothly.
The kwargs Conundrum in st.plotly_chart
The core of the issue lies in how Streamlit handles arguments passed to st.plotly_chart. Previously, some arguments that were intended for Plotly's internal configuration might have been accepted directly as keyword arguments. However, as libraries evolve, best practices change. Streamlit, in its continuous effort to provide a cleaner and more maintainable API, has been transitioning to a more structured way of passing configuration options. This has led to the deprecation of accepting arbitrary kwargs directly for Plotly configurations. The warning message, "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," is Streamlit's way of gently nudging developers towards this new approach. It’s important to note that this warning can appear even when you are not intentionally passing kwargs yourself. For instance, when you use arguments like width='content' or height='auto', which are documented and valid ways to control the chart's dimensions, Streamlit might internally be passing these through a mechanism that triggers the kwargs warning. This is often a side effect of how the underlying libraries interact and how Streamlit manages these interactions for a seamless user experience. The goal is to ensure that all Plotly-specific configurations are funneled through the dedicated config argument, which provides a clear and organized way to manage these settings, preventing potential conflicts and making your code more readable and robust.
Why the Change? Promoting Clarity and Control
So, why the shift away from accepting kwargs directly? It all boils down to improving clarity and giving users more explicit control. When libraries allow a free-for-all with keyword arguments, it can become difficult to track where specific configurations are coming from. Is it a Streamlit argument, or is it a Plotly argument being passed through? This ambiguity can lead to confusion and make debugging a real headache. By introducing the config argument, Streamlit is essentially creating a dedicated "box" for all Plotly-specific settings. This means that when you want to tweak how your Plotly chart behaves—its margins, its interactivity, its layout options—you know exactly where to look: inside the config dictionary. This not only makes your code more self-explanatory but also aligns with Plotly's own best practices for customizing figures. The config argument acts as a single source of truth for all Plotly-related configurations, making it easier for Streamlit to manage and update the integration with Plotly without breaking existing applications. This structured approach helps in avoiding naming collisions between Streamlit's own parameters and Plotly's extensive array of configuration options. For example, if both Streamlit and Plotly were to introduce a parameter with the same name in the future, using kwargs directly could lead to unpredictable behavior. The config argument circumvents this issue entirely by providing a nested structure specifically for Plotly's settings, ensuring that Streamlit's core functionality remains distinct and unaffected by Plotly's internal argument handling.
Reproducing the Warning: A Simple Code Example
To help illustrate this, let's look at a straightforward code example that triggers the warning. Suppose you have a basic Streamlit app that displays a Plotly chart:
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 snippet, we create a simple Barpolar chart using Plotly and then display it using st.plotly_chart. We've explicitly set width="content", which is a documented way to tell Streamlit to let the chart determine its own width based on its container. However, when you run this code (especially on Streamlit version 1.50.0 or newer), you'll likely see the deprecation warning about kwargs even though you haven't passed any extra, unexpected keyword arguments. The width="content" parameter is a valid and intended use of the st.plotly_chart function, but its internal implementation is what's causing the warning to surface. This indicates that the warning isn't necessarily a bug in your code, but rather an artifact of the library's internal handling of arguments related to sizing and configuration. Streamlit's development team is aware of this and is working on refining how these arguments are processed to provide a cleaner user experience. The expected behavior is that using documented parameters like width should not result in a deprecation warning related to kwargs, as these are considered part of the standard API for controlling chart dimensions. The current behavior, where such a warning appears, suggests a slight mismatch between the warning's trigger and the actual user intent when using these specific documented arguments.
The Expected Behavior vs. Current Reality
The ideal scenario, as you'd expect from robust documentation, is that using the width argument with a value like "content" should work seamlessly without triggering any deprecation warnings. The documentation guides users to transition from the older use_container_width parameter to the more flexible width argument. Therefore, it's reasonable to assume that this transition should be smooth and free of unexpected warnings. The expected behavior is that st.plotly_chart(fig, width="content") should simply render the chart with its width adjusted to fit the container, and nothing more. No warnings, no fuss. However, the current behavior indicates that Streamlit's internal logic for detecting and warning about kwargs is being too sensitive. It's catching the width argument (and potentially others related to sizing or layout) as if it were an arbitrary, deprecated keyword argument, even though it's a documented and intended parameter. This can be frustrating because it might lead developers to believe they are using the API incorrectly, when in fact, they are following the provided guidelines. This situation often arises when a library undergoes significant refactoring, and the warning system hasn't been perfectly tuned to differentiate between truly arbitrary kwargs and specific, documented parameters that are now handled differently internally. The Streamlit team has acknowledged this and is working on refining the warning mechanism to be more precise. The ultimate goal is to ensure that warnings accurately reflect actual API misuse and don't distract from valid usage patterns. This often involves fine-tuning the argument parsing and validation logic within the Streamlit framework.
Is This a Regression? Yes, It Appears To Be.
Many users have reported that this behavior is indeed a regression. In previous versions of Streamlit, using arguments like width="content" with st.plotly_chart did not produce this kwargs deprecation warning. This suggests that a recent change in Streamlit's codebase, likely related to how it handles Plotly integrations or argument parsing, has inadvertently introduced this issue. Regressions can be frustrating, but they are a natural part of software development. The fact that it's recognized as a regression means the Streamlit team is aware of it and is likely prioritizing a fix. The development community often relies on such issue reports to identify and resolve these kinds of problems quickly. By clearly marking this as a regression, users are helping the Streamlit team understand the impact and urgency of the issue. It signals that a functionality that previously worked as expected is no longer doing so, which can disrupt existing applications and workflows. This makes it crucial for the development team to investigate the specific code changes that might have led to this behavior and implement a solution that restores the previous, seamless experience. The key takeaway here is that while the warning might seem alarming, it's a sign that the library is evolving, and sometimes these evolutionary steps can have minor, temporary side effects. The Streamlit team's commitment to addressing regressions ensures that the library remains stable and reliable for its users.
Debugging and Looking Ahead
For those encountering this warning, the good news is that your code is likely correct, and it's the library's internal handling that needs a tweak. The warning itself, while potentially annoying, is informative. It points towards a specific area of change in Streamlit's API management. The Streamlit version mentioned (1.50.0) is a key piece of information, as it helps pinpoint when this behavior might have been introduced. Understanding the debug info provided by users, such as the Streamlit version, Python version, operating system, and browser, is crucial for developers to reproduce and diagnose the issue accurately. The kwargs warning essentially indicates that Streamlit is moving towards a more rigid structure for passing configurations to Plotly, primarily through the config dictionary. While width="content" might not be a direct kwargs you're passing, the internal mechanisms might be interpreting it as such. The best path forward is to keep your Streamlit updated, as the team is actively working on resolving such regressions. In the meantime, if the warning is particularly disruptive, you might explore if there are alternative ways to control the chart's width that bypass this specific warning trigger, although the recommended approach is to use the documented parameters. The community's role in reporting these issues is invaluable. By providing clear reproducible examples and detailed debug information, users help accelerate the development and release of fixes. As Streamlit continues to mature, such refinements in argument handling and warning systems are expected, ultimately leading to a more polished and user-friendly experience for everyone building amazing data apps.
Conclusion: Embracing Evolution
While the kwargs deprecation warning in st.plotly_chart when using documented parameters like width="content" might seem like a minor hiccup, it's a sign of Streamlit's ongoing commitment to a clean and robust API. The shift towards using the config argument for Plotly-specific settings is a positive step that enhances code clarity and maintainability. The fact that this warning can appear even with correct usage points to a need for refinement in Streamlit's warning triggers, and the team is actively addressing this as a regression. As developers, staying updated with Streamlit releases is the best way to benefit from these improvements. By understanding the underlying reasons for these changes and contributing with clear bug reports, we can all help make Streamlit an even better platform for building interactive data applications. The Streamlit community is vibrant and supportive, and issues like these are often resolved quickly thanks to active participation.
For further insights into Streamlit and its best practices, I recommend checking out the official Streamlit Documentation. Additionally, for more on Plotly's customization options, the Plotly Python Documentation is an excellent resource.
