language: Fix language detection for injected syntax layers (#41111)
Vitaly Slobodin
created
Closes #40632
**TL;DR:** The `wrap selections in tag` action was unavailable in ERB
files, even when the cursor was positioned in HTML content (outside of
Ruby code blocks). This happened because `syntax_layer_at()` incorrectly
returned the Ruby language for positions that were actually in HTML.
**NOTE:** I am not familiar with that part of Zed so it could be that
the fix here is completely incorrect.
Previously, `syntax_layer_at` incorrectly reported injected languages
(e.g., Ruby in ERB files) even when the cursor was in the base language
content (HTML). This broke actions like `wrap selections in tag` that
depend on language-specific configuration.
The issue had two parts:
1. Missing start boundary check: The filter only checked if a layer's
end was after the cursor (`end_byte() > offset`), not if it started
before, causing layers outside the cursor position to be included. See
the `BEFORE` video: when I click on the HTML part it reports `Ruby`
language instead of `HTML`.
2. Wrong boundary reference for injections: For injected layers with
`included_sub_ranges` (like Ruby code blocks in ERB), checking the root
node boundaries returned the entire file range instead of the actual
injection ranges.
This fix:
- Adds the containment check using half-open range semantics [start,
end) for root node boundaries. That ensures proper reporting of the
detected language when a cursor (`|`) is located right after the
injection:
```
<body>
<%= yield %>|
</body>
```
- Checks `included_sub_ranges` for injected layers to determine if the
cursor is actually within an injection
- Falls back to root node boundaries for base layers without sub-ranges.
This is the original behavior.
Fixes ERB language support where actions should be available based on
the cursor's actual language context. I think that also applies to some
other template languages like HEEX (Phoenix) and `*.pug`. On short
videos below you can see how I navigate through the ERB template and the
terminal on the right outputs the detected language if you apply the
following patch:
```diff
diff --git i/crates/editor/src/editor.rs w/crates/editor/src/editor.rs
index 15af61f5d2..54a8e0ae37 100644
--- i/crates/editor/src/editor.rs
+++ w/crates/editor/src/editor.rs
@@ -10671,6 +10671,7 @@ impl Editor {
for selection in self.selections.disjoint_anchors_arc().iter() {
if snapshot
.language_at(selection.start)
+ .inspect(|language| println!("Detected language: {:?}", language))
.and_then(|lang| lang.config().wrap_characters.as_ref())
.is_some()
{
```
**Before:**
https://github.com/user-attachments/assets/3f8358f4-d343-462e-b6b1-3f1f2e8c533d
**After:**
https://github.com/user-attachments/assets/c1b9f065-1b44-45a2-8a24-76b7d812130d
Here is the ERB template:
```
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<style>
/* Email styles need to be inline */
</style>
</head>
<body>
<%= yield %>
</body>
</html>
```
Release Notes:
- N/A