column_config.ProgressColumn clips raw data values in "Download as CSV" export

[dmhpx]

Checklist

• I have searched the existing issues for similar issues.
• I added a very descriptive title to this issue.
• I have provided sufficient information below to help reproduce this issue.

Summary

When using st.column_config.ProgressColumn, setting a max_value that is lower than the actual data value (e.g., data is 11 but max_value is 10) causes the built-in "Download as CSV" feature to export the clipped max_value instead of the original raw data. This leads to data integrity loss in exports.

Reproducible Code Example

import streamlit as st
import pandas as pd

df = pd.DataFrame({"Real Data": [7, 11, 3, 2]})

st.dataframe(
    df,
    column_config={
        "Real Data": st.column_config.ProgressColumn(
            "Displayed Data",
            min_value=0,
            max_value=10,
            format="%d",
        ),
    },
)

Steps To Reproduce

1. Run the app.
2. Observe that the second row shows a "Full" progress bar of 11/10 (visually correct).
3. Click the built-in "Download as CSV" button in the dataframe toolbar.
4. Open the CSV. Attached an example here.

Expected Behavior

The "Actual Data" column in the CSV should show

7
11
3
2

Current Behavior

Right now the CSV shows

7
10
3
2

Is this a regression?

• Yes, this used to work in a previous version.

Debug info

• Streamlit version: 1.55.0
• Python version: 3.12.10
• Operating System: Windows 11 Pro
• Browser: Edge

Additional Information

No response

[github-actions]

If this issue affects you, please react with a 👍 (thumbs up emoji) to the initial post.

Your feedback helps us prioritize which bugs to investigate and address first.

[github-actions]

This is a confirmed bug in the ProgressColumn frontend implementation. When values exceed the configured max_value (or fall below min_value), the column correctly displays the original value in the cell label (e.g., "11") but clamps the underlying cell.data.value to the max_value for the progress bar visualization. The problem is that getCellValue() in ProgressColumn.ts (line 248) returns this clamped cell.data.value instead of the original raw value. The CSV exporter (useDataExporter.ts) calls getCellValue() to build export data, so it writes the clamped value (10) instead of the original (11).

The fix is straightforward: getCellValue() should return the original value. Notably, the copyData field (line 229) already stores the correct original value as String(cellData), so the raw data is preserved in the cell — it's just not used by getCellValue(). One approach would be to parse copyData back to a number, or to store the original value in a separate field in cell.data and return that from getCellValue().

Related Issues

• #9944 — The inverse problem in BarChartColumn/LineChartColumn: y_min and y_max are not honored when input values exceed the defined limits. Both issues relate to how column types handle out-of-range values in column_config.
• #10863 — "Enable Download as CSV for large dataframes." Different root cause but affects the same CSV export feature in st.dataframe.
• #12307 — "Horizontal bar chart column for st.dataframe." An enhancement to ProgressColumn that may need to consider the same clamping vs. raw-value distinction.

---

This is an automated triage comment using opus-4.6-thinking. Please verify the suggested labels and related issues.