Ensure process os is set before xterm link handler is registered

Fixes #62586

src/vs/workbench/contrib/terminal/browser/terminalInstance.ts

@@ -426,16 +426,23 @@ export class TerminalInstance implements ITerminalInstance {
 		this._xterm.on('key', (key, ev) => this._onKey(key, ev));
 
 		if (this._processManager) {
-			if (this._processManager.os === platform.OperatingSystem.Windows) {
-				this._xterm.winptyCompatInit();
-			}
 			this._processManager.onProcessData(data => this._onProcessData(data));
 			this._xterm.on('data', data => this._processManager!.write(data));
 			// TODO: How does the cwd work on detached processes?
-			this._linkHandler = this._instantiationService.createInstance(TerminalLinkHandler, this._xterm, platform.platform, this._processManager);
 			this.processReady.then(async () => {
 				this._linkHandler.processCwd = await this._processManager!.getInitialCwd();
 			});
+			// Init winpty compat and link handler after process creation as they rely on the
+			// underlying process OS
+			this._processManager.onProcessReady(() => {
+				if (!this._processManager) {
+					return;
+				}
+				if (this._processManager.os === platform.OperatingSystem.Windows) {
+					this._xterm.winptyCompatInit();
+				}
+				this._linkHandler = this._instantiationService.createInstance(TerminalLinkHandler, this._xterm, platform.platform, this._processManager);
+			});
 		}
 		this._xterm.on('focus', () => this._onFocus.fire(this));
 
@@ -579,7 +586,7 @@ export class TerminalInstance implements ITerminalInstance {
 
 			if (this._processManager) {
 				this._widgetManager = new TerminalWidgetManager(this._wrapperElement);
-				this._linkHandler.setWidgetManager(this._widgetManager);
+				this._processManager.onProcessReady(() => this._linkHandler.setWidgetManager(this._widgetManager));
 			}
 
 			const computedStyle = window.getComputedStyle(this._container);