Revert "perf(core): avoid cloning unchanged log fields"

This reverts commit fb88613.

Author: carderne

packages/core/src/logger.ts

@@ -322,44 +322,33 @@ function filterKeys(obj: unknown, keys: Set<string>, depth = 0): any {
 
   if (Array.isArray(obj)) {
     const isTruncated = obj.length > MAX_ARRAY_LENGTH;
-    const length = isTruncated ? MAX_ARRAY_LENGTH : obj.length;
-    let filteredItems: unknown[] | undefined = isTruncated ? [] : undefined;
-
-    for (let index = 0; index < length; index++) {
-      const item = obj[index];
-      const filteredItem = filterKeys(item, keys, depth + 1);
-
-      if (filteredItems) {
-        filteredItems.push(filteredItem);
-      } else if (filteredItem !== item) {
-        filteredItems = obj.slice(0, index);
-        filteredItems.push(filteredItem);
-      }
-    }
+    const items = (isTruncated ? obj.slice(0, MAX_ARRAY_LENGTH) : obj).map((item) =>
+      filterKeys(item, keys, depth + 1)
+    );
 
     if (isTruncated) {
-      filteredItems!.push(`[truncated ${obj.length - MAX_ARRAY_LENGTH} more items]`);
+      items.push(`[truncated ${obj.length - MAX_ARRAY_LENGTH} more items]`);
     }
 
-    return filteredItems ?? obj;
+    return items;
   }
 
-  let filteredObj: Record<string, unknown> | undefined;
+  const filteredObj: any = {};
 
   for (const [key, value] of Object.entries(obj)) {
-    const filteredValue = keys.has(key.toLowerCase())
-      ? value
-        ? `[filtered ${prettyPrintBytes(value)}]`
-        : value
-      : filterKeys(value, keys, depth + 1);
-
-    if (filteredValue !== value) {
-      filteredObj ??= { ...(obj as Record<string, unknown>) };
-      filteredObj[key] = filteredValue;
+    if (keys.has(key.toLowerCase())) {
+      if (value) {
+        filteredObj[key] = `[filtered ${prettyPrintBytes(value)}]`;
+      } else {
+        filteredObj[key] = value;
+      }
+      continue;
     }
+
+    filteredObj[key] = filterKeys(value, keys, depth + 1);
   }
 
-  return filteredObj ?? obj;
+  return filteredObj;
 }
 
 function truncateString(value: string): string {

packages/core/test/logger.test.ts

@@ -208,27 +208,4 @@ describe("redact()", () => {
 
     expect(result.connectionString).toMatch(/^\[filtered/);
   });
-
-  it("preserves references when no values need redaction or truncation", () => {
-    const nested = { keep: "this stays" };
-    const value = { nested, values: ["one", "two"] };
-
-    const result = redact(value);
-
-    expect(result).toBe(value);
-    expect((result as typeof value).nested).toBe(nested);
-    expect((result as typeof value).values).toBe(value.values);
-  });
-
-  it("returns a redacted copy without mutating the input", () => {
-    const nested = { token: "secret" };
-    const value = { nested };
-
-    const result = redact(value) as typeof value;
-
-    expect(result).not.toBe(value);
-    expect(result.nested).not.toBe(nested);
-    expect(result.nested.token).toMatch(/^\[filtered/);
-    expect(nested.token).toBe("secret");
-  });
 });