CSS Mirror Editing with Sourcemaps: Known Issues and Feedback

This issue is where we will collect feedback specific to using CSS Mirroring with source-mapped files. Support for mirroring edits across source maps is a follow-up for #476 that enables using this feature with languages such as SASS or with CSS which gets bundled during build. See CSS Mirror Editing with Sourcemapped files (Sass, React...) for more details and a demo of how the feature works.

Testing Pre-requisites:

• Edge 102.0.1216.0+
• A build step that generates source maps for CSS

Known Issues

5. Changes to selectors are not mirrored back to the original source file.

6. New properties added at the end of the block don't indent correctly if a source map entry exists for the closing curly brace } (webpack + sass-loader behavior).

7. New properties added at the end of the block get inserted before the last property of the block if no source map entry exists for the closing curly brace } (default sass CLI behavior).

8. Creating/editing property names to use invalid characters (e.g. ```-``-`) can cause mapping to get out-of-sync.

9. Inserting new properties into an empty block (e.g. after deleting all existing properties) inserts them before the selector if no source map entry exists for the closing curly brace } (default sass CLI behavior).

10. Editing a selector in a single-line source block (e.g. .foo { color: #fff }) causes property edits in that block to be incorrect.

11. Changes applied due to panel-level undo/redo (e.g. Ctrl+Z) don't get mirrored to original source (they do work if undoing while editing a property directly).

No implementation files, tests, or entry points are named. Reproduce the listed cases using Edge 102.0.1216.0+ and a CSS build step that generates source maps, then compare mirrored edits with the original source. Done means the listed selector, insertion, indentation, invalid-name, empty-block, single-line, and undo/redo cases stay synchronized.