Introduce asString to call toString() safely on process stdout/stderr

extensions/ql-vscode/src/codeql-cli/cli.ts

@@ -19,6 +19,7 @@ import type { CliConfig } from "../config";
 import type { DistributionProvider } from "./distribution";
 import { FindDistributionResultKind } from "./distribution";
 import {
+  asString,
   assertNever,
   getErrorMessage,
   getErrorStack,
@@ -1605,8 +1606,8 @@ export function spawnServer(
   command: string[],
   commandArgs: string[],
   logger: Logger,
-  stderrListener: (data: any) => void,
-  stdoutListener?: (data: any) => void,
+  stderrListener: (data: unknown) => void,
+  stdoutListener?: (data: unknown) => void,
   progressReporter?: ProgressReporter,
 ): ChildProcessWithoutNullStreams {
   // Enable verbose logging.
@@ -1626,7 +1627,7 @@ export function spawnServer(
     );
   }
 
-  let lastStdout: any = undefined;
+  let lastStdout: unknown = undefined;
   child.stdout!.on("data", (data) => {
     lastStdout = data;
   });
@@ -1643,7 +1644,7 @@ export function spawnServer(
     // If the process exited abnormally, log the last stdout message,
     // It may be from the jvm.
     if (code !== 0 && lastStdout !== undefined) {
-      void logger.log(`Last stdout was "${lastStdout.toString()}"`);
+      void logger.log(`Last stdout was "${asString(lastStdout)}"`);
     }
   });
   child.stderr!.on("data", stderrListener);

extensions/ql-vscode/src/common/helpers-pure.ts

@@ -68,6 +68,20 @@ export function asError(e: unknown): Error {
   return e instanceof Error ? e : new Error(String(e));
 }
 
+/**
+ * Converts a unknown value to a string, using `toString` if possible,
+ * or returning the human-readable strings "null" or "undefined".
+ */
+export function asString(x: unknown): string {
+  if (x === null) {
+    return "null";
+  } else if (x === undefined) {
+    return "undefined";
+  } else {
+    return x.toString();
+  }
+}
+
 /**
  * Get error message when the error may have come from a method from the `child_process` module.
  */

extensions/ql-vscode/src/language-support/language-client.ts

@@ -5,6 +5,7 @@ import { LanguageClient, NotificationType } from "vscode-languageclient/node";
 import { shouldDebugLanguageServer, spawnServer } from "../codeql-cli/cli";
 import type { QueryServerConfig } from "../config";
 import { languageServerLogger } from "../common/logging/vscode";
+import { asString } from "../common/helpers-pure";
 
 /**
  * Managing the language client and corresponding server process for CodeQL.
@@ -74,9 +75,9 @@ async function spawnLanguageServer(
         args,
         languageServerLogger,
         (data) =>
-          languageServerLogger.log(data.toString(), { trailingNewline: false }),
+          languageServerLogger.log(asString(data), { trailingNewline: false }),
         (data) =>
-          languageServerLogger.log(data.toString(), { trailingNewline: false }),
+          languageServerLogger.log(asString(data), { trailingNewline: false }),
         progressReporter,
       );
       return { writer: child.stdin!, reader: child.stdout! };

extensions/ql-vscode/src/query-server/query-server-client.ts

@@ -18,6 +18,7 @@ import type { ProgressCallback, ProgressTask } from "../common/vscode/progress";
 import { withProgress } from "../common/vscode/progress";
 import { ServerProcess } from "./server-process";
 import type { App } from "../common/app";
+import { asString } from "../common/helpers-pure";
 
 type ServerOpts = {
   logger: Logger;
@@ -214,7 +215,7 @@ export class QueryServerClient extends DisposableObject {
       args,
       this.logger,
       (data) =>
-        this.activeQueryLogger.log(data.toString(), {
+        this.activeQueryLogger.log(asString(data), {
           trailingNewline: false,
         }),
       undefined, // no listener for stdout