From 633c5fbf0fb95f68fa7f311d1920fc5babcc3785 Mon Sep 17 00:00:00 2001
From: Michael Davis <mcarsondavis@gmail.com>
Date: Sun, 8 Jun 2025 14:46:17 -0400
Subject: [PATCH] Update language loader before refreshing theme in
 `:config-reload`

Since locals are handled during parsing instead of highlighting with
tree-house, we need to call `helix_core::syntax::Loader::set_scopes`
before parsing any documents. During `:config-reload` we previously
reloaded the `Loader` and re-parsed documents and _then_ updated the
theme. So documents were parsed before `Loader::set_scopes` was called
on the new loader.

With this change the `refresh_language_config` helper is inlined into
`refresh_config`. Updating the `Editor`'s `ArcSwap` of the loader is
done before updating the theme so that the `load_configured_theme`
helper can call `set_scopes` with on the new loader.
---
 helix-term/src/application.rs | 40 +++++++++++++++++------------------
 1 file changed, 19 insertions(+), 21 deletions(-)

diff --git a/helix-term/src/application.rs b/helix-term/src/application.rs
index 6f3485a87..eadda721d 100644
--- a/helix-term/src/application.rs
+++ b/helix-term/src/application.rs
@@ -384,32 +384,30 @@ impl Application {
         }
     }
 
-    /// refresh language config after config change
-    fn refresh_language_config(&mut self) -> Result<(), Error> {
-        let lang_loader = helix_core::config::user_lang_loader()?;
-
-        self.editor.syn_loader.store(Arc::new(lang_loader));
-        let loader = self.editor.syn_loader.load();
-        for document in self.editor.documents.values_mut() {
-            document.detect_language(&loader);
-            let diagnostics = Editor::doc_diagnostics(
-                &self.editor.language_servers,
-                &self.editor.diagnostics,
-                document,
-            );
-            document.replace_diagnostics(diagnostics, &[], None);
-        }
-
-        Ok(())
-    }
-
     fn refresh_config(&mut self) {
         let mut refresh_config = || -> Result<(), Error> {
             let default_config = Config::load_default()
                 .map_err(|err| anyhow::anyhow!("Failed to load config: {}", err))?;
-            self.refresh_language_config()?;
-            // Refresh theme after config change
+
+            // Update the syntax language loader before setting the theme. Setting the theme will
+            // call `Loader::set_scopes` which must be done before the documents are re-parsed for
+            // the sake of locals highlighting.
+            let lang_loader = helix_core::config::user_lang_loader()?;
+            self.editor.syn_loader.store(Arc::new(lang_loader));
             Self::load_configured_theme(&mut self.editor, &default_config);
+
+            // Re-parse any open documents with the new language config.
+            let lang_loader = self.editor.syn_loader.load();
+            for document in self.editor.documents.values_mut() {
+                document.detect_language(&lang_loader);
+                let diagnostics = Editor::doc_diagnostics(
+                    &self.editor.language_servers,
+                    &self.editor.diagnostics,
+                    document,
+                );
+                document.replace_diagnostics(diagnostics, &[], None);
+            }
+
             self.terminal
                 .reconfigure(default_config.editor.clone().into())?;
             // Store new config