[ty] Make auto-import completions opt-in via an experimental option

Instead of waiting to land auto-import until it is "ready
for users," it'd be nicer to get incremental progress merged
to `main`. By making it an experimental opt-in, we avoid making
the default completion experience worse but permit developers
and motivated users to try it.

crates/ty_ide/src/completion.rs

@@ -12,7 +12,17 @@ use crate::find_node::covering_node;
 use crate::goto::DefinitionsOrTargets;
 use crate::{Db, all_symbols};
 
-pub fn completion(db: &dyn Db, file: File, offset: TextSize) -> Vec<DetailedCompletion<'_>> {
+#[derive(Clone, Debug, Default)]
+pub struct CompletionSettings {
+    pub auto_import: bool,
+}
+
+pub fn completion<'db>(
+    db: &'db dyn Db,
+    settings: &CompletionSettings,
+    file: File,
+    offset: TextSize,
+) -> Vec<DetailedCompletion<'db>> {
     let parsed = parsed_module(db, file).load(db);
 
     let Some(target_token) = CompletionTargetTokens::find(&parsed, offset) else {
@@ -39,6 +49,7 @@ pub fn completion(db: &dyn Db, file: File, offset: TextSize) -> Vec<DetailedComp
         }
         CompletionTargetAst::Scoped { node } => {
             let mut completions = model.scoped_completions(node);
+            if settings.auto_import {
                 for symbol in all_symbols(db, "") {
                     completions.push(Completion {
                         name: ast::name::Name::new(&symbol.symbol.name),
@@ -47,6 +58,7 @@ pub fn completion(db: &dyn Db, file: File, offset: TextSize) -> Vec<DetailedComp
                         builtin: false,
                     });
                 }
+            }
             completions
         }
     };
@@ -518,7 +530,7 @@ mod tests {
     use crate::completion::{DetailedCompletion, completion};
     use crate::tests::{CursorTest, cursor_test};
 
-    use super::token_suffix_by_kinds;
+    use super::{CompletionSettings, token_suffix_by_kinds};
 
     #[test]
     fn token_suffixes_match() {
@@ -3073,7 +3085,8 @@ from os.<CURSOR>
             predicate: impl Fn(&DetailedCompletion) -> bool,
             snapshot: impl Fn(&DetailedCompletion) -> String,
         ) -> String {
-            let completions = completion(&self.db, self.cursor.file, self.cursor.offset);
+            let settings = CompletionSettings::default();
+            let completions = completion(&self.db, &settings, self.cursor.file, self.cursor.offset);
             if completions.is_empty() {
                 return "<No completions found>".to_string();
             }
@@ -3096,7 +3109,8 @@ from os.<CURSOR>
 
         #[track_caller]
         fn assert_completions_include(&self, expected: &str) {
-            let completions = completion(&self.db, self.cursor.file, self.cursor.offset);
+            let settings = CompletionSettings::default();
+            let completions = completion(&self.db, &settings, self.cursor.file, self.cursor.offset);
 
             assert!(
                 completions
@@ -3108,7 +3122,8 @@ from os.<CURSOR>
 
         #[track_caller]
         fn assert_completions_do_not_include(&self, unexpected: &str) {
-            let completions = completion(&self.db, self.cursor.file, self.cursor.offset);
+            let settings = CompletionSettings::default();
+            let completions = completion(&self.db, &settings, self.cursor.file, self.cursor.offset);
 
             assert!(
                 completions

crates/ty_ide/src/lib.rs

@@ -26,7 +26,7 @@ mod symbols;
 mod workspace_symbols;
 
 pub use all_symbols::{AllSymbolInfo, all_symbols};
-pub use completion::completion;
+pub use completion::{CompletionSettings, completion};
 pub use doc_highlights::document_highlights;
 pub use document_symbols::document_symbols;
 pub use goto::{goto_declaration, goto_definition, goto_type_definition};

crates/ty_server/src/server/api/requests/completion.rs

@@ -7,7 +7,7 @@ use lsp_types::{
 };
 use ruff_db::source::{line_index, source_text};
 use ruff_source_file::OneIndexed;
-use ty_ide::completion;
+use ty_ide::{CompletionSettings, completion};
 use ty_project::ProjectDatabase;
 use ty_python_semantic::CompletionKind;
 
@@ -55,7 +55,10 @@ impl BackgroundDocumentRequestHandler for CompletionRequestHandler {
             &line_index,
             snapshot.encoding(),
         );
-        let completions = completion(db, file, offset);
+        let settings = CompletionSettings {
+            auto_import: snapshot.global_settings().is_auto_import_enabled(),
+        };
+        let completions = completion(db, &settings, file, offset);
         if completions.is_empty() {
             return Ok(None);
         }

crates/ty_server/src/session.rs

@@ -826,6 +826,7 @@ impl Session {
             .map_err(DocumentQueryError::InvalidUrl);
         DocumentSnapshot {
             resolved_client_capabilities: self.resolved_client_capabilities,
+            global_settings: self.global_settings.clone(),
             workspace_settings: key
                 .as_ref()
                 .ok()
@@ -1000,6 +1001,7 @@ impl Drop for MutIndexGuard<'_> {
 #[derive(Debug)]
 pub(crate) struct DocumentSnapshot {
     resolved_client_capabilities: ResolvedClientCapabilities,
+    global_settings: Arc<GlobalSettings>,
     workspace_settings: Arc<WorkspaceSettings>,
     position_encoding: PositionEncoding,
     document_query_result: Result<DocumentQuery, DocumentQueryError>,
@@ -1016,6 +1018,11 @@ impl DocumentSnapshot {
         self.position_encoding
     }
 
+    /// Returns the client settings for all workspaces.
+    pub(crate) fn global_settings(&self) -> &GlobalSettings {
+        &self.global_settings
+    }
+
     /// Returns the client settings for the workspace that this document belongs to.
     pub(crate) fn workspace_settings(&self) -> &WorkspaceSettings {
         &self.workspace_settings

crates/ty_server/src/session/options.rs

@@ -122,6 +122,12 @@ impl ClientOptions {
         self
     }
 
+    #[must_use]
+    pub fn with_experimental_auto_import(mut self, enabled: bool) -> Self {
+        self.global.experimental.get_or_insert_default().auto_import = Some(enabled);
+        self
+    }
+
     #[must_use]
     pub fn with_unknown(mut self, unknown: HashMap<String, Value>) -> Self {
         self.unknown = unknown;
@@ -149,6 +155,7 @@ impl GlobalOptions {
             .experimental
             .map(|experimental| ExperimentalSettings {
                 rename: experimental.rename.unwrap_or(true),
+                auto_import: experimental.auto_import.unwrap_or(false),
             })
             .unwrap_or_default();
 
@@ -293,6 +300,12 @@ impl Combine for DiagnosticMode {
 pub(crate) struct Experimental {
     /// Whether to enable the experimental symbol rename feature.
     pub(crate) rename: Option<bool>,
+    /// Whether to enable the experimental "auto-import" feature.
+    ///
+    /// At time of writing (2025-08-29), this feature is still
+    /// under active development. It may not work right or may be
+    /// incomplete.
+    pub(crate) auto_import: Option<bool>,
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize, Default)]

crates/ty_server/src/session/settings.rs

@@ -14,6 +14,10 @@ impl GlobalSettings {
     pub(crate) fn is_rename_enabled(&self) -> bool {
         self.experimental.rename
     }
+
+    pub(crate) fn is_auto_import_enabled(&self) -> bool {
+        self.experimental.auto_import
+    }
 }
 
 impl GlobalSettings {
@@ -25,6 +29,7 @@ impl GlobalSettings {
 #[derive(Clone, Default, Debug, PartialEq)]
 pub(crate) struct ExperimentalSettings {
     pub(super) rename: bool,
+    pub(super) auto_import: bool,
 }
 
 /// Resolved client settings for a specific workspace.

crates/ty_wasm/src/lib.rs

@@ -415,7 +415,11 @@ impl Workspace {
 
         let offset = position.to_text_size(&source, &index, self.position_encoding)?;
 
-        let completions = ty_ide::completion(&self.db, file_id.file, offset);
+        // NOTE: At time of writing, 2025-08-29, auto-import isn't
+        // ready to be enabled by default yet. Once it is, we should
+        // either just enable it or provide a way to configure it.
+        let settings = ty_ide::CompletionSettings { auto_import: false };
+        let completions = ty_ide::completion(&self.db, &settings, file_id.file, offset);
 
         Ok(completions
             .into_iter()