refactor: dedupe redact snapshot restore prelude

src/config/redact-snapshot.test.ts

@@ -798,6 +798,37 @@ describe("restoreRedactedValues", () => {
     expect(restoreRedactedValues_orig(undefined, { token: "x" }).ok).toBe(false);
   });
 
+  it("rejects non-object inputs", () => {
+    expect(restoreRedactedValues_orig("token-value", { token: "x" })).toEqual({
+      ok: false,
+      error: "input not an object",
+    });
+  });
+
+  it("returns a human-readable error when sentinel cannot be restored", () => {
+    const incoming = {
+      channels: { newChannel: { token: REDACTED_SENTINEL } },
+    };
+    const result = restoreRedactedValues_orig(incoming, {});
+    expect(result.ok).toBe(false);
+    expect(result.humanReadableMessage).toContain(REDACTED_SENTINEL);
+    expect(result.humanReadableMessage).toContain("channels.newChannel.token");
+  });
+
+  it("keeps unmatched wildcard array entries unchanged outside extension paths", () => {
+    const hints: ConfigUiHints = {
+      "custom.*": { sensitive: true },
+    };
+    const incoming = {
+      custom: { items: [REDACTED_SENTINEL] },
+    };
+    const original = {
+      custom: { items: ["original-secret-value"] },
+    };
+    const result = restoreRedactedValues(incoming, original, hints) as typeof incoming;
+    expect(result.custom.items[0]).toBe(REDACTED_SENTINEL);
+  });
+
   it("round-trips config through redact → restore", () => {
     const originalConfig = {
       gateway: { auth: { token: "gateway-auth-secret-token-value" }, port: 18789 },

src/config/redact-snapshot.ts

@@ -404,6 +404,20 @@ function toObjectRecord(value: unknown): Record<string, unknown> {
   return {};
 }
 
+function shouldPassThroughRestoreValue(incoming: unknown): boolean {
+  return incoming === null || incoming === undefined || typeof incoming !== "object";
+}
+
+function toRestoreArrayContext(
+  incoming: unknown,
+  prefix: string,
+): { incoming: unknown[]; path: string } | null {
+  if (!Array.isArray(incoming)) {
+    return null;
+  }
+  return { incoming, path: `${prefix}[]` };
+}
+
 function restoreArrayItemWithLookup(params: {
   item: unknown;
   index: number;
@@ -478,26 +492,25 @@ function restoreRedactedValuesWithLookup(
   prefix: string,
   hints: ConfigUiHints,
 ): unknown {
-  if (incoming === null || incoming === undefined) {
+  if (shouldPassThroughRestoreValue(incoming)) {
     return incoming;
   }
-  if (typeof incoming !== "object") {
-    return incoming;
-  }
-  if (Array.isArray(incoming)) {
+
+  const arrayContext = toRestoreArrayContext(incoming, prefix);
+  if (arrayContext) {
     // Note: If the user removed an item in the middle of the array,
     // we have no way of knowing which one. In this case, the last
     // element(s) get(s) chopped off. Not good, so please don't put
     // sensitive string array in the config...
-    const path = `${prefix}[]`;
+    const { incoming: incomingArray, path } = arrayContext;
     if (!lookup.has(path)) {
       if (!isExtensionPath(prefix)) {
-        return incoming;
+        return incomingArray;
       }
-      return restoreRedactedValuesGuessing(incoming, original, prefix, hints);
+      return restoreRedactedValuesGuessing(incomingArray, original, prefix, hints);
     }
     return mapRedactedArray({
-      incoming,
+      incoming: incomingArray,
       original,
       path,
       mapItem: (item, index, originalArray) =>
@@ -551,19 +564,18 @@ function restoreRedactedValuesGuessing(
   prefix: string,
   hints?: ConfigUiHints,
 ): unknown {
-  if (incoming === null || incoming === undefined) {
+  if (shouldPassThroughRestoreValue(incoming)) {
     return incoming;
   }
-  if (typeof incoming !== "object") {
-    return incoming;
-  }
-  if (Array.isArray(incoming)) {
+
+  const arrayContext = toRestoreArrayContext(incoming, prefix);
+  if (arrayContext) {
     // Note: If the user removed an item in the middle of the array,
     // we have no way of knowing which one. In this case, the last
     // element(s) get(s) chopped off. Not good, so please don't put
     // sensitive string array in the config...
-    const path = `${prefix}[]`;
-    return restoreGuessingArray(incoming, original, path, hints);
+    const { incoming: incomingArray, path } = arrayContext;
+    return restoreGuessingArray(incomingArray, original, path, hints);
   }
   const orig = toObjectRecord(original);
   const result: Record<string, unknown> = {};