Add support for insert_text_mode of a completion (#28171)

I wanted this for CONL (https://conl.dev )'s nascent langauge server,
and it seems like most of the support was already wired up on the LSP
side, so this surfaces it into the editor.

Release Notes:

- Added support for the `insert_text_mode` field of completions from the
language server protocol.

crates/editor/src/code_context_menus.rs

@@ -240,6 +240,7 @@ impl CompletionsMenu {
                 icon_path: None,
                 documentation: None,
                 confirm: None,
+                insert_text_mode: None,
                 source: CompletionSource::Custom,
             })
             .collect();

crates/editor/src/editor.rs

@@ -136,7 +136,7 @@ use task::{ResolvedTask, TaskTemplate, TaskVariables};
 pub use lsp::CompletionContext;
 use lsp::{
     CodeActionKind, CompletionItemKind, CompletionTriggerKind, DiagnosticSeverity,
-    InsertTextFormat, LanguageServerId, LanguageServerName,
+    InsertTextFormat, InsertTextMode, LanguageServerId, LanguageServerName,
 };
 
 use language::BufferSnapshot;
@@ -4442,6 +4442,7 @@ impl Editor {
                         word_range,
                         resolved: false,
                     },
+                    insert_text_mode: Some(InsertTextMode::AS_IS),
                     confirm: None,
                 }));
 
@@ -4687,7 +4688,13 @@ impl Editor {
             } else {
                 this.buffer.update(cx, |buffer, cx| {
                     let edits = ranges.iter().map(|range| (range.clone(), text));
-                    buffer.edit(edits, this.autoindent_mode.clone(), cx);
+                    let auto_indent = if completion.insert_text_mode == Some(InsertTextMode::AS_IS)
+                    {
+                        None
+                    } else {
+                        this.autoindent_mode.clone()
+                    };
+                    buffer.edit(edits, auto_indent, cx);
                 });
             }
             for (buffer, edits) in linked_edits {
@@ -18637,6 +18644,7 @@ fn snippet_completions(
                         .description
                         .clone()
                         .map(|description| CompletionDocumentation::SingleLine(description.into())),
+                    insert_text_mode: None,
                     confirm: None,
                 })
             })

crates/editor/src/editor_tests.rs

@@ -10235,6 +10235,62 @@ async fn test_completion_sort(cx: &mut TestAppContext) {
     });
 }
 
+#[gpui::test]
+async fn test_as_is_completions(cx: &mut TestAppContext) {
+    init_test(cx, |_| {});
+    let mut cx = EditorLspTestContext::new_rust(
+        lsp::ServerCapabilities {
+            completion_provider: Some(lsp::CompletionOptions {
+                ..Default::default()
+            }),
+            ..Default::default()
+        },
+        cx,
+    )
+    .await;
+    cx.lsp
+        .set_request_handler::<lsp::request::Completion, _, _>(move |_, _| async move {
+            Ok(Some(lsp::CompletionResponse::Array(vec![
+                lsp::CompletionItem {
+                    label: "unsafe".into(),
+                    text_edit: Some(lsp::CompletionTextEdit::Edit(lsp::TextEdit {
+                        range: lsp::Range {
+                            start: lsp::Position {
+                                line: 1,
+                                character: 2,
+                            },
+                            end: lsp::Position {
+                                line: 1,
+                                character: 3,
+                            },
+                        },
+                        new_text: "unsafe".to_string(),
+                    })),
+                    insert_text_mode: Some(lsp::InsertTextMode::AS_IS),
+                    ..Default::default()
+                },
+            ])))
+        });
+    cx.set_state("fn a() {}\n  nˇ");
+    cx.executor().run_until_parked();
+    cx.update_editor(|editor, window, cx| {
+        editor.show_completions(
+            &ShowCompletions {
+                trigger: Some("\n".into()),
+            },
+            window,
+            cx,
+        );
+    });
+    cx.executor().run_until_parked();
+
+    cx.update_editor(|editor, window, cx| {
+        editor.confirm_completion(&Default::default(), window, cx)
+    });
+    cx.executor().run_until_parked();
+    cx.assert_editor_state("fn a() {}\n  unsafeˇ");
+}
+
 #[gpui::test]
 async fn test_no_duplicated_completion_requests(cx: &mut TestAppContext) {
     init_test(cx, |_| {});