Memory/QMD: harden no-results parsing

src/memory/qmd-query-parser.ts

@@ -0,0 +1,47 @@
+import { createSubsystemLogger } from "../logging/subsystem.js";
+
+const log = createSubsystemLogger("memory");
+
+export type QmdQueryResult = {
+  docid?: string;
+  score?: number;
+  file?: string;
+  snippet?: string;
+  body?: string;
+};
+
+export function parseQmdQueryJson(stdout: string, stderr: string): QmdQueryResult[] {
+  const trimmedStdout = stdout.trim();
+  const trimmedStderr = stderr.trim();
+  const stdoutIsMarker = trimmedStdout.length > 0 && isQmdNoResultsOutput(trimmedStdout);
+  const stderrIsMarker = trimmedStderr.length > 0 && isQmdNoResultsOutput(trimmedStderr);
+  if (stdoutIsMarker || (!trimmedStdout && stderrIsMarker)) {
+    return [];
+  }
+  if (!trimmedStdout) {
+    const context = trimmedStderr ? ` (stderr: ${summarizeQmdStderr(trimmedStderr)})` : "";
+    const message = `stdout empty${context}`;
+    log.warn(`qmd query returned invalid JSON: ${message}`);
+    throw new Error(`qmd query returned invalid JSON: ${message}`);
+  }
+  try {
+    const parsed = JSON.parse(trimmedStdout) as unknown;
+    if (!Array.isArray(parsed)) {
+      throw new Error("qmd query JSON response was not an array");
+    }
+    return parsed as QmdQueryResult[];
+  } catch (err) {
+    const message = err instanceof Error ? err.message : String(err);
+    log.warn(`qmd query returned invalid JSON: ${message}`);
+    throw new Error(`qmd query returned invalid JSON: ${message}`, { cause: err });
+  }
+}
+
+function isQmdNoResultsOutput(raw: string): boolean {
+  const normalized = raw.trim().toLowerCase().replace(/\s+/g, " ");
+  return normalized === "no results found" || normalized === "no results found.";
+}
+
+function summarizeQmdStderr(raw: string): string {
+  return raw.length <= 120 ? raw : `${raw.slice(0, 117)}...`;
+}