Make getSupportedCodeFixes plugin test such that we dont need to update its baseline for every new error (#53070)

src/services/codeFixProvider.ts

@@ -49,6 +49,7 @@ function createCodeFixActionWorker(fixName: string, description: string, changes
 /** @internal */
 export function registerCodeFix(reg: CodeFixRegistration) {
     for (const error of reg.errorCodes) {
+        errorCodeToFixesArray = undefined;
         errorCodeToFixes.add(String(error), reg);
     }
     if (reg.fixIds) {
@@ -59,9 +60,10 @@ export function registerCodeFix(reg: CodeFixRegistration) {
     }
 }
 
+let errorCodeToFixesArray: readonly string[] | undefined;
 /** @internal */
 export function getSupportedErrorCodes(): readonly string[] {
-    return arrayFrom(errorCodeToFixes.keys());
+    return errorCodeToFixesArray ??= arrayFrom(errorCodeToFixes.keys());
 }
 
 function removeFixIdIfFixAllUnavailable(registration: CodeFixRegistration, diagnostics: Diagnostic[]) {

src/testRunner/unittests/tsserver/helpers.ts

@@ -560,7 +560,7 @@ export class TestSession extends ts.server.Session {
         }
         const response = super.executeCommand(request);
         if (this.logger.hasLevel(ts.server.LogLevel.verbose)) {
-            this.logger.info(`response:${ts.server.indent(JSON.stringify(response, undefined, 2))}`);
+            this.logger.info(`response:${ts.server.indent(JSON.stringify(response.response === ts.getSupportedCodeFixes() ? { ...response, response: "ts.getSupportedCodeFixes()" } : response, undefined, 2))}`);
             this.testhost.baselineHost("After request");
         }
         return response;

src/testRunner/unittests/tsserver/plugins.ts

@@ -195,7 +195,7 @@ describe("unittests:: tsserver:: plugins overriding getSupportedCodeFixes", () =
                                     return ["b"];
                                 default:
                                     // Make this stable list of single item so we dont have to update the baseline for every additional error
-                                    return [info.languageService.getSupportedCodeFixes(fileName)[0]];
+                                    return info.languageService.getSupportedCodeFixes(fileName);
                             }
                         };
                         return proxy;