Delegate TCL folding to server, fix bugs, and enhance stability

- Move TCL folding range computation from client to language server, avoiding duplicate regions.
- Serialize language server restarts to prevent multiple server instances running concurrently.
- Pin server-side Python dependencies to specific minor versions for improved stability and predictability.
- Make debug server connection non-fatal, allowing the language server to start even if the debugger isn't attached.
- Optimize semantic token generation by caching Tclint plugin commands.

client/src/extension.ts

@@ -15,7 +15,6 @@ import {
     cdlDocumentSymbolProvider,
     defDocumentSymbolProvider
 } from "./common/handlers"
-import { computeTclFoldingRanges } from "./common/folding"
 import { registerLogger, traceError, traceLog, traceVerbose } from "./common/log/logging"
 import {
     checkVersion,
@@ -30,7 +29,7 @@ import { loadServerDefaults } from "./common/setup"
 import { getLSClientTraceLevel } from "./common/utilities"
 import { createOutputChannel, onDidChangeConfiguration, registerCommand } from "./common/vscodeapi"
 
-let client: LanguageClient
+let client: LanguageClient | undefined
 
 export async function activate(context: vscode.ExtensionContext) {
     // This is required to get server name and module. This should be
@@ -62,7 +61,7 @@ export async function activate(context: vscode.ExtensionContext) {
     traceLog(`Module: ${serverInfo.module}`)
     traceVerbose(`Full Server Info: ${JSON.stringify(serverInfo)}`)
 
-    const runServer = async () => {
+    const runServerImpl = async () => {
         const interpreter = getInterpreterFromSetting(serverId)
         if (interpreter && interpreter.length > 0) {
             if (checkVersion(await resolveInterpreter(interpreter))) {
@@ -91,6 +90,16 @@ export async function activate(context: vscode.ExtensionContext) {
         )
     }
 
+    // Serialize server (re)starts. Overlapping triggers (interpreter change,
+    // config change, restart command, initial activation) would otherwise each
+    // read the stale module-level `client`, start a new server and leave the
+    // previous one running orphaned -> hints/hover shown multiple times.
+    let runServerQueue: Promise<void> = Promise.resolve()
+    const runServer = () => {
+        runServerQueue = runServerQueue.catch(() => undefined).then(() => runServerImpl())
+        return runServerQueue
+    }
+
     context.subscriptions.push(
         onDidChangePythonInterpreter(async () => {
             await runServer()
@@ -116,16 +125,9 @@ export async function activate(context: vscode.ExtensionContext) {
         }
     })
 
-    // Folding ranges for TCL (brace based)
-    const tclFoldingProvider = vscode.languages.registerFoldingRangeProvider(
-        [{ language: "tcl" }],
-        {
-            provideFoldingRanges(document: vscode.TextDocument) {
-                return computeTclFoldingRanges(document)
-            }
-        }
-    )
-    context.subscriptions.push(tclFoldingProvider)
+    // Folding ranges for TCL are provided by the language server
+    // (folding_range_provider in lsp_server.py). No client-side provider here to
+    // avoid duplicate folding regions.
 
     //
     const formatCdlProvider = vscode.languages.registerDocumentFormattingEditProvider(
@@ -219,26 +221,27 @@ export async function activate(context: vscode.ExtensionContext) {
     context.subscriptions.push(diagnosticCollectionCdl, diagnosticCollectionDef)
 
     // Check if the first line of the CDL file contains "MACHINE"
-    vscode.workspace.onDidOpenTextDocument((document) => {
-        if (document.languageId === "cdl" || document.languageId === "def") {
-            if (document.languageId === "cdl") {
-                diagnosticCollectionCdl.set(document.uri, diagnosticHandler(document))
-            } else if (document.languageId === "def") {
-                diagnosticCollectionDef.set(document.uri, diagnosticHandler(document))
+    context.subscriptions.push(
+        vscode.workspace.onDidOpenTextDocument((document) => {
+            if (document.languageId === "cdl" || document.languageId === "def") {
+                if (document.languageId === "cdl") {
+                    diagnosticCollectionCdl.set(document.uri, diagnosticHandler(document))
+                } else if (document.languageId === "def") {
+                    diagnosticCollectionDef.set(document.uri, diagnosticHandler(document))
+                }
             }
-        }
-    })
-
-    vscode.workspace.onDidChangeTextDocument((event) => {
-        const document = event.document
-        if (document.languageId === "cdl" || document.languageId === "def") {
-            if (document.languageId === "cdl") {
-                diagnosticCollectionCdl.set(document.uri, diagnosticHandler(document))
-            } else if (document.languageId === "def") {
-                diagnosticCollectionDef.set(document.uri, diagnosticHandler(document))
+        }),
+        vscode.workspace.onDidChangeTextDocument((event) => {
+            const document = event.document
+            if (document.languageId === "cdl" || document.languageId === "def") {
+                if (document.languageId === "cdl") {
+                    diagnosticCollectionCdl.set(document.uri, diagnosticHandler(document))
+                } else if (document.languageId === "def") {
+                    diagnosticCollectionDef.set(document.uri, diagnosticHandler(document))
+                }
             }
-        }
-    })
+        })
+    )
 }
 
 export function deactivate(): Thenable<void> | undefined {