[lib] Update convertClientDBThreadInfoToRawThreadInfo to validate `…

…ThreadCurrentUserInfo`

Summary:
Similar to D10313 and D10298, this diff addresses what we learned when testing D10297 that it's important that we validate the stringified JSON that we retrieve from `ClientDBThreadInfo`. Specifically, it's possible for `ClientDBThreadInfo` to have either stringified `MinimallyEncodedThreadCurrentInfo` or `ThreadCurrentInfo` (yes, we didn't end up renaming this to `LegacyThreadCurrentInfo` because we didn't end up needing a union type, but I will change the name for symmetry) stored in the `currentUser` field, and we should A. validate that the data is correctly formed and B. determine what format the data is in.

---

Depends on D10313

Test Plan: Will be tested along with changes in D10297 and D10298 and D10313.

Reviewers: ashoat, ginsu, tomek, rohan

Reviewed By: ashoat

Differential Revision: https://phab.comm.dev/D10314

lib/utils/thread-ops-utils.js

@@ -5,6 +5,7 @@ import invariant from 'invariant';
 import {
   minimallyEncodedMemberInfoValidator,
   minimallyEncodedRoleInfoValidator,
+  minimallyEncodedThreadCurrentUserInfoValidator,
 } from '../permissions/minimally-encoded-thread-permissions-validators.js';
 import type {
   MinimallyEncodedMemberInfo,
@@ -15,6 +16,7 @@ import {
   decodeMinimallyEncodedRawThreadInfo,
   minimallyEncodeMemberInfo,
   minimallyEncodeRoleInfo,
+  minimallyEncodeThreadCurrentUserInfo,
 } from '../types/minimally-encoded-thread-permissions-types.js';
 import { assertThreadType } from '../types/thread-types-enum.js';
 import {
@@ -23,6 +25,7 @@ import {
   type LegacyRawThreadInfo,
   legacyRoleInfoValidator,
   type RawThreadInfo,
+  threadCurrentUserInfoValidator,
 } from '../types/thread-types.js';
 
 function convertRawThreadInfoToClientDBThreadInfo(
@@ -75,6 +78,17 @@ function convertClientDBThreadInfoToRawThreadInfo(
       {},
     );
 
+  // 3. Validate and potentially minimally encode `rawCurrentUser`.
+  const rawCurrentUser = JSON.parse(clientDBThreadInfo.currentUser);
+  invariant(
+    minimallyEncodedThreadCurrentUserInfoValidator.is(rawCurrentUser) ||
+      threadCurrentUserInfoValidator.is(rawCurrentUser),
+    'rawCurrentUser must be valid [MinimallyEncoded]ThreadCurrentUserInfo',
+  );
+  const minimallyEncodedCurrentUser = rawCurrentUser.minimallyEncoded
+    ? rawCurrentUser
+    : minimallyEncodeThreadCurrentUserInfo(rawCurrentUser);
+
   let rawThreadInfo: MinimallyEncodedRawThreadInfo = {
     minimallyEncoded: true,
     id: clientDBThreadInfo.id,
@@ -88,7 +102,7 @@ function convertClientDBThreadInfoToRawThreadInfo(
     community: clientDBThreadInfo.community,
     members: minimallyEncodedMembers,
     roles: minimallyEncodedRoles,
-    currentUser: JSON.parse(clientDBThreadInfo.currentUser),
+    currentUser: minimallyEncodedCurrentUser,
     repliesCount: clientDBThreadInfo.repliesCount,
     pinnedCount: clientDBThreadInfo.pinnedCount,
   };