st.code ignores language argument if set to 'diff'

[lucasrodes]

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

st.code should highlight the text from argument body based on what's specified by argument language. According to the documentation, the list of available languages are specified by this list (react-syntax-highlighter). However, language='diff' does not work on my end even if it appears in the aforementioned list.

Reproducible Code Example

import streamlit as st

st.code("""
--- main
+++ develop
@@ -52,21 +52,19 @@
     "title": "Democracy index",
     "yAxis": {
         "max": 10,
-        "min": -10,
-        "facetDomain": "shared"
+        "min": -10
     },
""",
language="diff"
)

Steps To Reproduce

1. Run the reproducible code example as a streamlit app
2. Notice that the code syntax won't be highlighted.

Expected Behavior

The code should be highlighted. Lines starting with + should probably be green, and lines starting with - should be red.

Current Behavior

No syntax highlight happens, even if the language diff is listed in react-syntax-highlighter's list.

I am unsure if this affects other languages, but maybe does. If so, the list of languages should be edited to show the actual list of languages supported.

Is this a regression?

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

Debug info

• Streamlit version: 1.34
• Python version: 3.10.9
• Operating System: MacOS (also tested it on Linux Ubuntu)
• Browser: Arc (Chromium)

Additional Information

(maybe related: #5028)

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[raethlein]

Hey @lucasrodes, I am able to confirm this! It seems like if we remove this line (style={{}}) in StreamlitSyntaxHighlighter.tsx, the syntax seems to be highlighted correctly:

Why the style={{}} is used there and what removing it would have for side-effects requires a little bit more investigation.