Metadata-Version: 2.4
Name: jupyterlab_markdown_syntax_rendering_fix
Version: 0.6.9
Summary: Jupyterlab extension to fix a common issue with Markdown renderer where some race condition causes for the fenced code block to not have proper syntax highlighting
Project-URL: Homepage, https://github.com/stellarshenson/jupyterlab_markdown_syntax_rendering_fix
Project-URL: Bug Tracker, https://github.com/stellarshenson/jupyterlab_markdown_syntax_rendering_fix/issues
Project-URL: Repository, https://github.com/stellarshenson/jupyterlab_markdown_syntax_rendering_fix.git
Author-email: Stellars Henson <konrad.jelen+github@gmail.com>
License: BSD 3-Clause License
        
        Copyright (c) 2026, Stellars Henson
        All rights reserved.
        
        Redistribution and use in source and binary forms, with or without
        modification, are permitted provided that the following conditions are met:
        
        1. Redistributions of source code must retain the above copyright notice, this
           list of conditions and the following disclaimer.
        
        2. Redistributions in binary form must reproduce the above copyright notice,
           this list of conditions and the following disclaimer in the documentation
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        3. Neither the name of the copyright holder nor the names of its
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        THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
        AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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License-File: LICENSE
Keywords: jupyter,jupyterlab,jupyterlab-extension
Classifier: Framework :: Jupyter
Classifier: Framework :: Jupyter :: JupyterLab
Classifier: Framework :: Jupyter :: JupyterLab :: 4
Classifier: Framework :: Jupyter :: JupyterLab :: Extensions
Classifier: Framework :: Jupyter :: JupyterLab :: Extensions :: Prebuilt
Classifier: License :: OSI Approved :: BSD License
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.10
Classifier: Programming Language :: Python :: 3.11
Classifier: Programming Language :: Python :: 3.12
Classifier: Programming Language :: Python :: 3.13
Classifier: Programming Language :: Python :: 3.14
Requires-Python: >=3.10
Provides-Extra: dev
Requires-Dist: jupyter-builder>=1.0.0; extra == 'dev'
Requires-Dist: jupyterlab>=4; extra == 'dev'
Description-Content-Type: text/markdown

# jupyterlab_markdown_syntax_rendering_fix

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Fenced code blocks in rendered Markdown sometimes appear plain and uncoloured - the highlighting silently fails when a CodeMirror language chunk loads late or the language registry is not yet ready, and JupyterLab falls back to plain text. This extension restores the highlighting that was lost to that race.

## Features

- **Recovers lost highlighting** - re-applies syntax highlighting to fenced code blocks that rendered plain because the async highlighter missed the cache
- **Language agnostic** - works for any fenced language (bash, python, json, ...), independent of mermaid
- **Targets the cold-load race** - handles the case where a language chunk imports late or the registry is wired after an early render
- **Frontend only** - pure TypeScript labextension, no server component

## How it works

JupyterLab highlights fenced code in rendered Markdown with an async pass that fills a cache and a synchronous renderer that reads it. When the async highlight throws - a CodeMirror language-chunk import that rejects, or a registry that is not yet wired when an early render fires - the cache misses and the renderer emits a plain `<pre><code>`. This extension watches the application shell for those plain blocks and re-runs the highlight once the language is available.

- **Detect** - a `MutationObserver` flags any rendered `pre > code` that has a `language-*` class and text but no token `<span>` children
- **Recover** - re-runs the highlight through `IEditorLanguageRegistry` and swaps in the token spans, only when the highlighted text matches the source exactly so it never truncates content
- **Resilient** - retries a thrown highlight a few times with backoff while the language chunk finishes loading, then gives up cleanly and leaves the original plain text untouched
- **Unobtrusive** - each block is handled at most once, and editor and overlay churn is skipped to keep the observer cheap

## Requirements

- JupyterLab >= 4.0.0

## Install

To install the extension, execute:

```bash
pip install jupyterlab_markdown_syntax_rendering_fix
```

## Uninstall

To remove the extension, execute:

```bash
pip uninstall jupyterlab_markdown_syntax_rendering_fix
```
