From 387059c6b2b72c8c3f868c932401fccfc635c95a Mon Sep 17 00:00:00 2001
From: tidely <43219534+tidely@users.noreply.github.com>
Date: Mon, 8 Dec 2025 20:57:02 +0200
Subject: [PATCH] language: Add `LanguageName::new_static` to reduce
 allocations (#44380)

Implements a specialized constructor `LanguageName::new_static` for
`&'static str` which reduces allocations.

`LanguageName::new` always backs the underlying `SharedString` with an
owned `Arc<str>` even when a `&'static str` is passed. This makes us
allocate each time we create a new `LanguageName` no matter what.
Creating a specialized constructor for `&'static str` allows us to
essentially construct them for free.

Additional change:
Encourages using explicit constructors to avoid needless allocations.
Currently there were no instances of this trait being called where the
lifetime was not `'static` saving another 48 locations of allocation.

```rust
impl<'a> From<&'a str> for LanguageName {
    fn from(str: &'a str) -> Self {
        Self(SharedString::new(str))
    }
}

// to

impl From<&'static str> for LanguageName {
    fn from(str: &'static str) -> Self {
        Self(SharedString::new_static(str))
    }
}

```

Release Notes:

- N/A
---
 crates/dap_adapters/src/python.rs             |  2 +-
 crates/editor/src/editor_tests.rs             |  2 +-
 .../src/extension_store_test.rs               | 14 +++----
 crates/language/src/buffer_tests.rs           |  6 +--
 crates/language/src/language.rs               | 20 +++++-----
 crates/language/src/language_registry.rs      | 12 ++++--
 .../src/extension_lsp_adapter.rs              |  2 +-
 crates/languages/src/json.rs                  |  4 +-
 crates/languages/src/python.rs                |  4 +-
 crates/languages/src/tailwind.rs              | 40 ++++++++++++-------
 crates/languages/src/typescript.rs            |  6 +--
 crates/languages/src/vtsls.rs                 |  6 +--
 crates/project/src/project_tests.rs           |  4 +-
 crates/project/src/terminals.rs               |  4 +-
 crates/repl/src/kernels/mod.rs                |  2 +-
 crates/vim/src/normal/paste.rs                |  2 +-
 16 files changed, 74 insertions(+), 56 deletions(-)

diff --git a/crates/dap_adapters/src/python.rs b/crates/dap_adapters/src/python.rs
index 2f84193ac9343cac9ff1cf52eb648bad1cd77896..a45e16dc32180e1e4ed3b2ec01c92ad07ffc5e93 100644
--- a/crates/dap_adapters/src/python.rs
+++ b/crates/dap_adapters/src/python.rs
@@ -870,7 +870,7 @@ impl DebugAdapter for PythonDebugAdapter {
                 .active_toolchain(
                     delegate.worktree_id(),
                     base_path.into_arc(),
-                    language::LanguageName::new(Self::LANGUAGE_NAME),
+                    language::LanguageName::new_static(Self::LANGUAGE_NAME),
                     cx,
                 )
                 .await
diff --git a/crates/editor/src/editor_tests.rs b/crates/editor/src/editor_tests.rs
index fe1ce5cbdb7e5503136845630fcaaff7aade855a..75aa29be7a31ef6a4707e538ea21a2ca45aff395 100644
--- a/crates/editor/src/editor_tests.rs
+++ b/crates/editor/src/editor_tests.rs
@@ -9970,7 +9970,7 @@ async fn test_autoindent_disabled_with_nested_language(cx: &mut TestAppContext)
                     ],
                     ..Default::default()
                 },
-                name: LanguageName::new("rust"),
+                name: LanguageName::new_static("rust"),
                 ..Default::default()
             },
             Some(tree_sitter_rust::LANGUAGE.into()),
diff --git a/crates/extension_host/src/extension_store_test.rs b/crates/extension_host/src/extension_store_test.rs
index 6d3aadeb5ac498b3948d871a0a87f7ecf49b6bd8..54b090347ffad3ffed444827f5cb60c120d25ad7 100644
--- a/crates/extension_host/src/extension_store_test.rs
+++ b/crates/extension_host/src/extension_store_test.rs
@@ -307,9 +307,9 @@ async fn test_extension_store(cx: &mut TestAppContext) {
         assert_eq!(
             language_registry.language_names(),
             [
-                LanguageName::new("ERB"),
-                LanguageName::new("Plain Text"),
-                LanguageName::new("Ruby"),
+                LanguageName::new_static("ERB"),
+                LanguageName::new_static("Plain Text"),
+                LanguageName::new_static("Ruby"),
             ]
         );
         assert_eq!(
@@ -463,9 +463,9 @@ async fn test_extension_store(cx: &mut TestAppContext) {
         assert_eq!(
             language_registry.language_names(),
             [
-                LanguageName::new("ERB"),
-                LanguageName::new("Plain Text"),
-                LanguageName::new("Ruby"),
+                LanguageName::new_static("ERB"),
+                LanguageName::new_static("Plain Text"),
+                LanguageName::new_static("Ruby"),
             ]
         );
         assert_eq!(
@@ -523,7 +523,7 @@ async fn test_extension_store(cx: &mut TestAppContext) {
 
         assert_eq!(
             language_registry.language_names(),
-            [LanguageName::new("Plain Text")]
+            [LanguageName::new_static("Plain Text")]
         );
         assert_eq!(language_registry.grammar_names(), []);
     });
diff --git a/crates/language/src/buffer_tests.rs b/crates/language/src/buffer_tests.rs
index 6b5d2450fe72f46b728be0f5b151801fe2e7fa70..54e2ef4065460547f4a3f86db7d3a3986dff65eb 100644
--- a/crates/language/src/buffer_tests.rs
+++ b/crates/language/src/buffer_tests.rs
@@ -151,7 +151,7 @@ fn test_select_language(cx: &mut App) {
     let registry = Arc::new(LanguageRegistry::test(cx.background_executor().clone()));
     registry.add(Arc::new(Language::new(
         LanguageConfig {
-            name: LanguageName::new("Rust"),
+            name: LanguageName::new_static("Rust"),
             matcher: LanguageMatcher {
                 path_suffixes: vec!["rs".to_string()],
                 ..Default::default()
@@ -173,7 +173,7 @@ fn test_select_language(cx: &mut App) {
     )));
     registry.add(Arc::new(Language::new(
         LanguageConfig {
-            name: LanguageName::new("Make"),
+            name: LanguageName::new_static("Make"),
             matcher: LanguageMatcher {
                 path_suffixes: vec!["Makefile".to_string(), "mk".to_string()],
                 ..Default::default()
@@ -3728,7 +3728,7 @@ fn ruby_lang() -> Language {
 fn html_lang() -> Language {
     Language::new(
         LanguageConfig {
-            name: LanguageName::new("HTML"),
+            name: LanguageName::new_static("HTML"),
             block_comment: Some(BlockCommentConfig {
                 start: "<!--".into(),
                 prefix: "".into(),
diff --git a/crates/language/src/language.rs b/crates/language/src/language.rs
index 891e4842a49b81659c9e4a9bf42a0655ef30abcb..90a55592864a637a2692ffac6e30451827a479ea 100644
--- a/crates/language/src/language.rs
+++ b/crates/language/src/language.rs
@@ -982,7 +982,7 @@ impl<T> Override<T> {
 impl Default for LanguageConfig {
     fn default() -> Self {
         Self {
-            name: LanguageName::new(""),
+            name: LanguageName::new_static(""),
             code_fence_block_name: None,
             grammar: None,
             matcher: LanguageMatcher::default(),
@@ -2756,9 +2756,9 @@ mod tests {
         assert_eq!(
             languages.language_names(),
             &[
-                LanguageName::new("JSON"),
-                LanguageName::new("Plain Text"),
-                LanguageName::new("Rust"),
+                LanguageName::new_static("JSON"),
+                LanguageName::new_static("Plain Text"),
+                LanguageName::new_static("Rust"),
             ]
         );
 
@@ -2769,9 +2769,9 @@ mod tests {
         assert_eq!(
             languages.language_names(),
             &[
-                LanguageName::new("JSON"),
-                LanguageName::new("Plain Text"),
-                LanguageName::new("Rust"),
+                LanguageName::new_static("JSON"),
+                LanguageName::new_static("Plain Text"),
+                LanguageName::new_static("Rust"),
             ]
         );
 
@@ -2782,9 +2782,9 @@ mod tests {
         assert_eq!(
             languages.language_names(),
             &[
-                LanguageName::new("JSON"),
-                LanguageName::new("Plain Text"),
-                LanguageName::new("Rust"),
+                LanguageName::new_static("JSON"),
+                LanguageName::new_static("Plain Text"),
+                LanguageName::new_static("Rust"),
             ]
         );
 
diff --git a/crates/language/src/language_registry.rs b/crates/language/src/language_registry.rs
index af2b66316d133370a3c27f59da645cfff8d8aa66..6d91f5233ebd91de9ca02c4187c5a368c0323f2d 100644
--- a/crates/language/src/language_registry.rs
+++ b/crates/language/src/language_registry.rs
@@ -43,12 +43,18 @@ impl LanguageName {
         Self(SharedString::new(s))
     }
 
+    pub fn new_static(s: &'static str) -> Self {
+        Self(SharedString::new_static(s))
+    }
+
     pub fn from_proto(s: String) -> Self {
         Self(SharedString::from(s))
     }
+
     pub fn to_proto(&self) -> String {
         self.0.to_string()
     }
+
     pub fn lsp_id(&self) -> String {
         match self.0.as_ref() {
             "Plain Text" => "plaintext".to_string(),
@@ -87,9 +93,9 @@ impl std::fmt::Display for LanguageName {
     }
 }
 
-impl<'a> From<&'a str> for LanguageName {
-    fn from(str: &'a str) -> LanguageName {
-        LanguageName(SharedString::new(str))
+impl From<&'static str> for LanguageName {
+    fn from(str: &'static str) -> Self {
+        Self(SharedString::new_static(str))
     }
 }
 
diff --git a/crates/language_extension/src/extension_lsp_adapter.rs b/crates/language_extension/src/extension_lsp_adapter.rs
index 920bf07f5d1aa5702487369d93abceb0b37fd976..64fa12074b0344702888d87e6af8975049c3adc1 100644
--- a/crates/language_extension/src/extension_lsp_adapter.rs
+++ b/crates/language_extension/src/extension_lsp_adapter.rs
@@ -245,7 +245,7 @@ impl LspAdapter for ExtensionLspAdapter {
         // We can remove once the following extension versions no longer see any use:
         // - php@0.0.1
         if self.extension.manifest().id.as_ref() == "php" {
-            return HashMap::from_iter([(LanguageName::new("PHP"), "php".into())]);
+            return HashMap::from_iter([(LanguageName::new_static("PHP"), "php".into())]);
         }
 
         self.extension
diff --git a/crates/languages/src/json.rs b/crates/languages/src/json.rs
index 00bb265967f83ee9a95c034cc0bbcbf63e952647..5168ba6e6188da62745df72a031f1d3bcda9a5d2 100644
--- a/crates/languages/src/json.rs
+++ b/crates/languages/src/json.rs
@@ -286,8 +286,8 @@ impl LspAdapter for JsonLspAdapter {
 
     fn language_ids(&self) -> HashMap<LanguageName, String> {
         [
-            (LanguageName::new("JSON"), "json".into()),
-            (LanguageName::new("JSONC"), "jsonc".into()),
+            (LanguageName::new_static("JSON"), "json".into()),
+            (LanguageName::new_static("JSONC"), "jsonc".into()),
         ]
         .into_iter()
         .collect()
diff --git a/crates/languages/src/python.rs b/crates/languages/src/python.rs
index fc2f91121e96e0c0709b4d5e8d0666102ce9866d..db914ad2d062dcce77bb12c9b777da3db9a7750f 100644
--- a/crates/languages/src/python.rs
+++ b/crates/languages/src/python.rs
@@ -903,7 +903,7 @@ impl ContextProvider for PythonContextProvider {
 
 fn selected_test_runner(location: Option<&Arc<dyn language::File>>, cx: &App) -> TestRunner {
     const TEST_RUNNER_VARIABLE: &str = "TEST_RUNNER";
-    language_settings(Some(LanguageName::new("Python")), location, cx)
+    language_settings(Some(LanguageName::new_static("Python")), location, cx)
         .tasks
         .variables
         .get(TEST_RUNNER_VARIABLE)
@@ -1397,7 +1397,7 @@ async fn venv_to_toolchain(venv: PythonEnvironment, fs: &dyn Fs) -> Option<Toolc
             .to_str()?
             .to_owned()
             .into(),
-        language_name: LanguageName::new("Python"),
+        language_name: LanguageName::new_static("Python"),
         as_json: serde_json::to_value(data).ok()?,
     })
 }
diff --git a/crates/languages/src/tailwind.rs b/crates/languages/src/tailwind.rs
index 3cf9dd05a165f04dd4be1d1b0a9cf30288db167a..6375b70c427399579d6c557879b6f357eb87bd3f 100644
--- a/crates/languages/src/tailwind.rs
+++ b/crates/languages/src/tailwind.rs
@@ -174,20 +174,32 @@ impl LspAdapter for TailwindLspAdapter {
 
     fn language_ids(&self) -> HashMap<LanguageName, String> {
         HashMap::from_iter([
-            (LanguageName::new("Astro"), "astro".to_string()),
-            (LanguageName::new("HTML"), "html".to_string()),
-            (LanguageName::new("Gleam"), "html".to_string()),
-            (LanguageName::new("CSS"), "css".to_string()),
-            (LanguageName::new("JavaScript"), "javascript".to_string()),
-            (LanguageName::new("TypeScript"), "typescript".to_string()),
-            (LanguageName::new("TSX"), "typescriptreact".to_string()),
-            (LanguageName::new("Svelte"), "svelte".to_string()),
-            (LanguageName::new("Elixir"), "phoenix-heex".to_string()),
-            (LanguageName::new("HEEX"), "phoenix-heex".to_string()),
-            (LanguageName::new("ERB"), "erb".to_string()),
-            (LanguageName::new("HTML+ERB"), "erb".to_string()),
-            (LanguageName::new("PHP"), "php".to_string()),
-            (LanguageName::new("Vue.js"), "vue".to_string()),
+            (LanguageName::new_static("Astro"), "astro".to_string()),
+            (LanguageName::new_static("HTML"), "html".to_string()),
+            (LanguageName::new_static("Gleam"), "html".to_string()),
+            (LanguageName::new_static("CSS"), "css".to_string()),
+            (
+                LanguageName::new_static("JavaScript"),
+                "javascript".to_string(),
+            ),
+            (
+                LanguageName::new_static("TypeScript"),
+                "typescript".to_string(),
+            ),
+            (
+                LanguageName::new_static("TSX"),
+                "typescriptreact".to_string(),
+            ),
+            (LanguageName::new_static("Svelte"), "svelte".to_string()),
+            (
+                LanguageName::new_static("Elixir"),
+                "phoenix-heex".to_string(),
+            ),
+            (LanguageName::new_static("HEEX"), "phoenix-heex".to_string()),
+            (LanguageName::new_static("ERB"), "erb".to_string()),
+            (LanguageName::new_static("HTML+ERB"), "erb".to_string()),
+            (LanguageName::new_static("PHP"), "php".to_string()),
+            (LanguageName::new_static("Vue.js"), "vue".to_string()),
         ])
     }
 }
diff --git a/crates/languages/src/typescript.rs b/crates/languages/src/typescript.rs
index eeca5ebb6f752ac8c5d375394fe6ba4c318552c6..b02fb40ac7d84eba03766bcdfc19fb0eee04a6ca 100644
--- a/crates/languages/src/typescript.rs
+++ b/crates/languages/src/typescript.rs
@@ -822,9 +822,9 @@ impl LspAdapter for TypeScriptLspAdapter {
 
     fn language_ids(&self) -> HashMap<LanguageName, String> {
         HashMap::from_iter([
-            (LanguageName::new("TypeScript"), "typescript".into()),
-            (LanguageName::new("JavaScript"), "javascript".into()),
-            (LanguageName::new("TSX"), "typescriptreact".into()),
+            (LanguageName::new_static("TypeScript"), "typescript".into()),
+            (LanguageName::new_static("JavaScript"), "javascript".into()),
+            (LanguageName::new_static("TSX"), "typescriptreact".into()),
         ])
     }
 }
diff --git a/crates/languages/src/vtsls.rs b/crates/languages/src/vtsls.rs
index a057f403368bf1400740ce6f96182dc638a14077..b21ae1a4de24e0a8035e8fda7d61223b5143c5ff 100644
--- a/crates/languages/src/vtsls.rs
+++ b/crates/languages/src/vtsls.rs
@@ -296,9 +296,9 @@ impl LspAdapter for VtslsLspAdapter {
 
     fn language_ids(&self) -> HashMap<LanguageName, String> {
         HashMap::from_iter([
-            (LanguageName::new("TypeScript"), "typescript".into()),
-            (LanguageName::new("JavaScript"), "javascript".into()),
-            (LanguageName::new("TSX"), "typescriptreact".into()),
+            (LanguageName::new_static("TypeScript"), "typescript".into()),
+            (LanguageName::new_static("JavaScript"), "javascript".into()),
+            (LanguageName::new_static("TSX"), "typescriptreact".into()),
         ])
     }
 }
diff --git a/crates/project/src/project_tests.rs b/crates/project/src/project_tests.rs
index 24b2280edee55a0131c73f6b91b3cea7adc6bbad..4a724809c2c4196be49122e7065abe8ec8f139a7 100644
--- a/crates/project/src/project_tests.rs
+++ b/crates/project/src/project_tests.rs
@@ -746,7 +746,7 @@ async fn test_running_multiple_instances_of_a_single_server_in_one_worktree(
                     worktree_id,
                     path: rel_path("project-b/source_file.py").into(),
                 },
-                LanguageName::new("Python"),
+                LanguageName::new_static("Python"),
                 cx,
             )
         })
@@ -762,7 +762,7 @@ async fn test_running_multiple_instances_of_a_single_server_in_one_worktree(
                     worktree_id,
                     path: rel_path("project-b/source_file.py").into(),
                 },
-                LanguageName::new("Python"),
+                LanguageName::new_static("Python"),
                 cx,
             )
         })
diff --git a/crates/project/src/terminals.rs b/crates/project/src/terminals.rs
index 81172f57744ac3d03532a263e70a483496db24f6..9e9c9fe423ca7cc619851f05dc66f14a9c626712 100644
--- a/crates/project/src/terminals.rs
+++ b/crates/project/src/terminals.rs
@@ -111,7 +111,7 @@ impl Project {
             );
         let toolchains = project_path_contexts
             .filter(|_| detect_venv)
-            .map(|p| self.active_toolchain(p, LanguageName::new("Python"), cx))
+            .map(|p| self.active_toolchain(p, LanguageName::new_static("Python"), cx))
             .collect::<Vec<_>>();
         let lang_registry = self.languages.clone();
         cx.spawn(async move |project, cx| {
@@ -311,7 +311,7 @@ impl Project {
             );
         let toolchains = project_path_contexts
             .filter(|_| detect_venv)
-            .map(|p| self.active_toolchain(p, LanguageName::new("Python"), cx))
+            .map(|p| self.active_toolchain(p, LanguageName::new_static("Python"), cx))
             .collect::<Vec<_>>();
         let remote_client = self.remote_client.clone();
         let shell = match &remote_client {
diff --git a/crates/repl/src/kernels/mod.rs b/crates/repl/src/kernels/mod.rs
index 02952010f3c510fdcc12176610ed85d94c1e0e80..ab8f27121e91cca444d27fed5c5d728426166610 100644
--- a/crates/repl/src/kernels/mod.rs
+++ b/crates/repl/src/kernels/mod.rs
@@ -81,7 +81,7 @@ pub fn python_env_kernel_specifications(
     worktree_id: WorktreeId,
     cx: &mut App,
 ) -> impl Future<Output = Result<Vec<KernelSpecification>>> + use<> {
-    let python_language = LanguageName::new("Python");
+    let python_language = LanguageName::new_static("Python");
     let toolchains = project.read(cx).available_toolchains(
         ProjectPath {
             worktree_id,
diff --git a/crates/vim/src/normal/paste.rs b/crates/vim/src/normal/paste.rs
index dffabde8fd84081762d7cb62bfa14a2f4ab4a59d..978c882f059e1f4cf40089de4a4af746d8526b54 100644
--- a/crates/vim/src/normal/paste.rs
+++ b/crates/vim/src/normal/paste.rs
@@ -717,7 +717,7 @@ mod test {
         cx.update_global(|store: &mut SettingsStore, cx| {
             store.update_user_settings(cx, |settings| {
                 settings.project.all_languages.languages.0.insert(
-                    LanguageName::new("Rust").0,
+                    LanguageName::new_static("Rust").0,
                     LanguageSettingsContent {
                         auto_indent_on_paste: Some(false),
                         ..Default::default()