Fix Plotly Chart Deprecation Warning In Streamlit

by Alex Johnson 50 views

Hey there, data visualization enthusiasts! If you've been working with Streamlit and plotting charts using the plotly_chart function, you might have recently stumbled upon a rather pesky deprecation warning. It pops up specifically when you try to control the width or height of your charts using parameters like width="content". The warning message usually goes something like: "Variable keyword arguments for st.plotly_chart have been deprecated and will be removed in a future release. Use the config argument instead..." Now, this can be a bit confusing, especially when you're not explicitly passing any variable keyword arguments, but rather using documented parameters as intended. Let's dive into what's causing this, why it's happening, and most importantly, how you can get rid of it and keep your Streamlit apps running smoothly.

Understanding the Plotly Chart Deprecation Warning

So, what exactly is this plotly_chart kwargs deprecation warning all about? It stems from a change within the Streamlit library aimed at streamlining how users interact with Plotly charts. In essence, the developers decided to deprecate the direct use of arbitrary keyword arguments (kwargs) for passing configuration options to Plotly charts. Instead, they're encouraging the use of a dedicated config argument. This approach is designed to make the API cleaner, more predictable, and less prone to conflicts with other arguments that might be passed to st.plotly_chart itself. However, the implementation seems to have a slight hiccup. The warning is being triggered even when you use officially supported parameters like width="content" or height="content" to adjust your chart's dimensions. This is a bit of a snag because, as users, we expect these documented parameters to work without throwing deprecation warnings. It feels like the warning mechanism is a little too sensitive, flagging legitimate uses as if they were deprecated practices. This can be particularly frustrating when you're trying to achieve a specific layout for your visualizations and are greeted with an error message that seems out of place. The core issue is that Streamlit's internal logic for detecting deprecated kwargs is being triggered by the width parameter, even though width is a valid and intended argument for controlling chart size.

Why is This Happening? A Deeper Dive

Let's get a bit more technical for a moment to understand why this warning is showing up unexpectedly. When you call st.plotly_chart(fig, width="content"), Streamlit processes this command. Internally, Streamlit has a mechanism to check for any kwargs that are passed to the plotly_chart function. The intention behind this check is to catch any arguments that are not explicitly defined as function parameters, thereby guiding users towards the preferred config argument for Plotly-specific settings. The code snippet that often causes this confusion looks something like this: if kwargs: show_deprecation_warning(...). The problem arises because, in some versions of Streamlit or in specific usage scenarios, arguments like width or height might be passed down to Plotly in a way that the Streamlit function's internal kwargs check interprets as arbitrary, even though they are standard ways to control chart dimensions. This is a classic case of an overly broad implementation of a good idea. The goal of discouraging arbitrary kwargs is sound – it promotes better code structure and clarity. However, the way the st.plotly_chart function handles its own parameters, especially those related to layout and sizing, can inadvertently trigger this warning. This means that even if you're following the documentation and using parameters like width="content", the underlying system might still be flagging it as an unrecognized keyword argument. It's like telling a security guard you have a valid ticket, but they're only checking if you have a specific type of ticket, and yours, while valid, doesn't match their immediate expectation. This can lead to a situation where your charts render perfectly fine, but the console is cluttered with warnings, making it harder to spot genuine issues.

The Impact on Your Workflow

This deprecation warning for plotly_chart kwargs might seem like a minor annoyance, but it can actually have a ripple effect on your development workflow. Firstly, it introduces noise into your console output. When you're debugging, you want clear, concise messages. A flood of deprecation warnings can easily mask more critical errors, making it harder to pinpoint the real problems in your code. You might spend precious debugging time trying to decipher whether a warning is something you need to address or just a false alarm. Secondly, it can create uncertainty. As a developer, you want to be confident that you're using libraries correctly. Seeing a deprecation warning, even for a parameter that seems to be working, can make you question your understanding of the API. This might lead you to spend extra time researching or experimenting, when in reality, the parameter is functioning as expected, and it's just the warning system that's misfiring. Furthermore, if you're collaborating with others or deploying your application, these warnings can give the impression of an unmaintained or unstable codebase, even if that's not the case. It can be a small but persistent source of friction. The goal of Streamlit is to make app development faster and more intuitive, and these kinds of unexpected warnings can, unfortunately, slow that process down.

Reproducible Example: Seeing the Warning in Action

To help everyone understand precisely what we're talking about, let's look at a concrete example. The following Python code snippet demonstrates how to trigger this plotly_chart kwargs deprecation warning in Streamlit. It's a straightforward setup involving importing the necessary libraries, creating a simple Plotly figure, and then displaying it using st.plotly_chart with the width="content" parameter.

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")

When you run this code in a Streamlit application, you'll notice that the chart renders correctly. The Barpolar chart, with its specified radius and theta values, will appear as expected, and the width="content" parameter will attempt to make the chart responsive to its container. However, alongside the visual output, you'll see the deprecation warning message in your terminal or Streamlit's log output. This message will likely indicate that variable keyword arguments are deprecated and suggest using the config parameter instead. This is the core of the issue: the warning appears despite width="content" being a documented and functional parameter for controlling the display size of the chart. It highlights the mismatch between the warning's trigger and the user's actual intent and the parameter's documented behavior. The warning isn't stopping the code from running, but it's a sign of an underlying issue in how Streamlit is interpreting or handling these arguments, making the development experience less smooth than it could be.

Step-by-Step to Reproduce

  1. Set up your environment: Ensure you have Streamlit and Plotly installed (pip install streamlit plotly).
  2. Create a Python file: Save the code example above (or a similar one using st.plotly_chart with width="content" or height="content") into a Python file (e.g., app.py).
  3. Run the Streamlit application: Open your terminal, navigate to the directory where you saved the file, and run the command: streamlit run app.py.
  4. Observe the output: Your Streamlit app will launch in your browser. Look at your terminal where you ran the streamlit run command. You should see the deprecation warning message printed there, even though the plot itself is displayed correctly.

This simple reproduction path clearly illustrates the problem: the warning is present and potentially misleading when using standard features of the st.plotly_chart function.

The Expected vs. Current Behavior

It's crucial to understand the intended behavior versus what's currently happening when you use st.plotly_chart with size parameters. The discrepancy here is what constitutes the bug.

Expected Behavior: Smooth Sailing with Size Arguments

When the Streamlit documentation mentions parameters like width and height for st.plotly_chart, the expectation is that these are valid arguments that can be used to control the dimensions of the displayed plot. Specifically, using values like "content" for width or height is intended to make the chart adapt to its container, a very common and useful feature for responsive web applications. Therefore, the expected behavior is that using st.plotly_chart(fig, width="content") or st.plotly_chart(fig, height="content") should simply adjust the chart's size accordingly without generating any deprecation warnings related to keyword arguments. Users should be able to leverage these documented features without encountering confusing or misleading messages. The transition from older methods (like use_container_width) to these new arguments should be seamless, and the system should recognize these parameters as legitimate, not as arbitrary keywords needing deprecation.

Current Behavior: The Unwanted Warning

As observed in the reproducible code example, the current behavior is that passing width="content" (or potentially height="content") to st.plotly_chart does trigger a deprecation warning. This warning states that "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 is problematic because, as we've established, width="content" is not a variable keyword argument in the sense of being arbitrary or undocumented. It's a specific, documented parameter for controlling chart dimensions. The warning, therefore, is misleading. It suggests that the user is doing something wrong or outdated, when in fact, they are using the function as intended according to its documentation. This situation creates unnecessary confusion and clutters the developer's console with messages that don't reflect a genuine misuse of the API.

Is This a Regression?

Yes, this is indeed a regression. Based on user reports and the nature of the issue, this behavior was not present in previous versions of Streamlit. Users could previously set the width or height of their Plotly charts using parameters like "content" without encountering deprecation warnings. The introduction of this warning with the use of these specific, documented parameters indicates that a change in Streamlit's internal handling of st.plotly_chart arguments has inadvertently broken this functionality or, more accurately, introduced a false positive for the deprecation warning. Regressions are particularly disruptive because they affect existing, working codebases, forcing developers to adapt to new, unexpected behaviors. In this case, code that was functioning correctly now produces noise, impacting the clarity of the development environment.

Debugging Information and Environment Details

To aid in diagnosing and fixing this issue, here's a snapshot of the environment where the plotly_chart kwargs deprecation warning was observed:

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

This information provides a clear context for the development team to investigate. The version numbers are key for pinpointing potential code changes in Streamlit that might have led to this behavior. Knowing the OS and browser helps rule out environment-specific rendering issues, although in this case, the warning is primarily a console/log output problem. The fact that it's a regression suggests a specific code change introduced around or before Streamlit version 1.50.0 is the likely culprit.

How to Resolve the plotly_chart Kwargs Warning

While the ideal solution is for the Streamlit developers to correct this false positive, there are a couple of ways you might navigate this issue in the meantime.

  1. Update Streamlit: The first and most recommended step is to check if a newer version of Streamlit has been released that addresses this specific regression. Development teams often fix such issues quickly once they are identified. Try updating Streamlit to the latest stable version (pip install --upgrade streamlit) and see if the warning disappears.

  2. Use use_container_width=True (if applicable): If your goal is simply to make the chart fill its container width, the parameter use_container_width=True often achieves a similar visual result and might not trigger the warning. However, note that width="content" offers more granular control, and use_container_width might behave differently in certain complex layouts.

  3. Suppress Warnings (Use with Caution): As a last resort, you can choose to suppress deprecation warnings within your Streamlit app. You can do this using Python's warnings module. Add the following code snippet at the beginning of your Streamlit script:

    import warnings
from streamlit.runtime.warnings import show_deprecation_warning

# Filter out the specific deprecation warning from Streamlit's plotly_chart
warnings.filterwarnings("ignore", message=".*Variable keyword arguments for st.plotly_chart have been deprecated.*")
# or a more targeted filter if you know the exact message

    Use this method with extreme caution. While it silences the warning, it also hides potential issues. If Streamlit does eventually remove support for width="content" or deprecates it properly, this filter will prevent you from seeing that future warning, potentially breaking your app later.

Conclusion

The plotly_chart kwargs deprecation warning when using size parameters like width="content" is a known issue and a regression that can cause unnecessary confusion during development. While the intention behind deprecating arbitrary keyword arguments is to promote cleaner APIs, the current implementation seems to be overly sensitive. The best course of action is to keep your Streamlit library updated, as the Streamlit team is likely working on a fix. If you need an immediate workaround, explore alternative parameters or, as a temporary measure, consider selectively filtering warnings, but do so mindfully. Clear communication and accurate warnings are key to a smooth development experience, and we hope to see this particular hiccup resolved soon.

For more information on Plotly and its integration with Streamlit, you can always refer to the official documentation: