Infer modifyOtherKeys support (#16270)

packages/cli/src/ui/utils/terminalCapabilityManager.ts

@@ -43,14 +43,13 @@ export class TerminalCapabilityManager {
   // eslint-disable-next-line no-control-regex
   private static readonly MODIFY_OTHER_KEYS_REGEX = /\x1b\[>4;(\d+)m/;
 
+  private detectionComplete = false;
   private terminalBackgroundColor: TerminalBackgroundColor;
   private kittySupported = false;
   private kittyEnabled = false;
-  private detectionComplete = false;
   private terminalName: string | undefined;
-  private modifyOtherKeysSupported = false;
-  private modifyOtherKeysEnabled = false;
-  private bracketedPasteEnabled = false;
+  private modifyOtherKeysSupported?: boolean;
+  private deviceAttributesSupported = false;
 
   private constructor() {}
 
@@ -187,6 +186,7 @@ export class TerminalCapabilityManager {
           );
           if (match) {
             deviceAttributesReceived = true;
+            this.deviceAttributesSupported = true;
             cleanup();
           }
         }
@@ -215,13 +215,17 @@ export class TerminalCapabilityManager {
       if (this.kittySupported) {
         enableKittyKeyboardProtocol();
         this.kittyEnabled = true;
-      } else if (this.modifyOtherKeysSupported) {
+      } else if (
+        this.modifyOtherKeysSupported === true ||
+        // If device attributes were received it's safe to try enabling
+        // anyways, since it will be ignored if unsupported
+        (this.modifyOtherKeysSupported === undefined &&
+          this.deviceAttributesSupported)
+      ) {
         enableModifyOtherKeys();
-        this.modifyOtherKeysEnabled = true;
       }
       // Always enable bracketed paste since it'll be ignored if unsupported.
       enableBracketedPasteMode();
-      this.bracketedPasteEnabled = true;
     } catch (e) {
       debugLogger.warn('Failed to enable keyboard protocols:', e);
     }
@@ -239,14 +243,6 @@ export class TerminalCapabilityManager {
     return this.kittyEnabled;
   }
 
-  isBracketedPasteEnabled(): boolean {
-    return this.bracketedPasteEnabled;
-  }
-
-  isModifyOtherKeysEnabled(): boolean {
-    return this.modifyOtherKeysEnabled;
-  }
-
   private parseColor(rHex: string, gHex: string, bHex: string): string {
     const parseComponent = (hex: string) => {
       const val = parseInt(hex, 16);