fix(memory): preserve QMD results in noisy command output (#115023)

packages/memory-host-sdk/src/host/qmd-query-parser.test.ts

@@ -25,6 +25,35 @@ complete`,
     expect(results).toEqual([{ docid: "abc", score: 0.5 }]);
   });
 
+  it.each([
+    {
+      name: "bracketed log prefix",
+      stdout: '[qmd] initializing search\n[{"docid":"abc","score":0.5}]',
+    },
+    {
+      name: "bracketed log with an empty array",
+      stdout: '[qmd] filters=[]\n[{"docid":"abc","score":0.5}]',
+    },
+    {
+      name: "bracketed log with result-shaped data",
+      stdout: '[qmd] previous=[{"docid":"stale","score":1}]\n[{"docid":"abc","score":0.5}]',
+    },
+    {
+      name: "leading no-results marker",
+      stdout: 'warning: no results found\n[{"docid":"abc","score":0.5}]',
+    },
+    {
+      name: "trailing no-results marker",
+      stdout: '[{"docid":"abc","score":0.5}]\nwarning: no results found',
+    },
+    {
+      name: "bracketed no-results marker",
+      stdout: '[qmd] warning: no results found\n[{"docid":"abc","score":0.5}]',
+    },
+  ])("preserves query results after a $name", ({ stdout }) => {
+    expect(parseQmdQueryJson(stdout, "")).toEqual([{ docid: "abc", score: 0.5 }]);
+  });
+
   it("preserves explicit qmd line metadata when present", () => {
     const results = parseQmdQueryJson(
       '[{"docid":"abc","score":0.5,"start_line":4,"end_line":6,"snippet":"@@ -10,1\\nignored"}]',
@@ -58,6 +87,9 @@ complete`,
   it("treats prefixed no-results marker output as an empty result set", () => {
     expect(parseQmdQueryJson("warning: no results found", "")).toStrictEqual([]);
     expect(parseQmdQueryJson("", "[qmd] warning: no results found\n")).toStrictEqual([]);
+    expect(
+      parseQmdQueryJson("[qmd] initializing search\nwarning: no results found", ""),
+    ).toStrictEqual([]);
   });
 
   it("keeps bounded stderr context UTF-16 safe", () => {
@@ -81,6 +113,12 @@ complete`,
     );
   });
 
+  it("rejects malformed bracket-heavy stdout without repeated rescanning", () => {
+    expect(() => parseQmdQueryJson("[".repeat(4_096), "")).toThrow(
+      /qmd query returned invalid JSON/i,
+    );
+  });
+
   it("routes invalid-output diagnostics through console capture", () => {
     vi.stubEnv("VITEST", "");
     vi.stubEnv("NODE_ENV", "production");

packages/memory-host-sdk/src/host/qmd-query-parser.ts

@@ -21,9 +21,8 @@ export type QmdQueryResult = {
 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)) {
+  if (!trimmedStdout && stderrIsMarker) {
     return [];
   }
   if (!trimmedStdout) {
@@ -39,6 +38,9 @@ export function parseQmdQueryJson(stdout: string, stderr: string): QmdQueryResul
     }
     const noisyPayload = extractFirstJsonArray(trimmedStdout);
     if (!noisyPayload) {
+      if (isQmdNoResultsOutput(trimmedStdout)) {
+        return [];
+      }
       throw new Error("qmd query JSON response was not an array");
     }
     const fallback = parseQmdQueryResultArray(noisyPayload);
@@ -127,26 +129,43 @@ function parseQmdLineNumber(value: unknown): number | undefined {
   return typeof value === "number" && Number.isSafeInteger(value) && value > 0 ? value : undefined;
 }
 
-/** Extract the first complete JSON array from noisy stdout. */
+/** Extract the first complete, standalone JSON result array from noisy stdout. */
 function extractFirstJsonArray(raw: string): string | null {
-  const start = raw.indexOf("[");
-  if (start < 0) {
-    return null;
-  }
+  let start = -1;
   let depth = 0;
   let inString = false;
   let escaped = false;
-  for (let i = start; i < raw.length; i += 1) {
+  let atLineStart = true;
+
+  for (let i = 0; i < raw.length; i += 1) {
     const char = raw[i];
     if (char === undefined) {
       break;
     }
+
+    if (start < 0) {
+      if (char === "\n") {
+        atLineStart = true;
+        continue;
+      }
+      if (atLineStart && (char === " " || char === "\t" || char === "\r")) {
+        continue;
+      }
+      // QMD emits result arrays on their own line; log fields can contain arrays too.
+      if (!atLineStart || char !== "[") {
+        atLineStart = false;
+        continue;
+      }
+      start = i;
+      depth = 1;
+      atLineStart = false;
+      continue;
+    }
+
     if (inString) {
       if (escaped) {
         escaped = false;
-        continue;
-      }
-      if (char === "\\") {
+      } else if (char === "\\") {
         escaped = true;
       } else if (char === '"') {
         inString = false;
@@ -159,12 +178,17 @@ function extractFirstJsonArray(raw: string): string | null {
     }
     if (char === "[") {
       depth += 1;
-    } else if (char === "]") {
-      depth -= 1;
-      if (depth === 0) {
-        return raw.slice(start, i + 1);
-      }
+      continue;
     }
+    if (char !== "]" || --depth !== 0) {
+      continue;
+    }
+
+    const candidate = raw.slice(start, i + 1);
+    if (parseQmdQueryResultArray(candidate) !== null) {
+      return candidate;
+    }
+    start = -1;
   }
   return null;
 }