Bug: Preset staging main - collection sync issues
Status: RESOLVED
Priority: --
Resolution: INVALID
Created: 2020-05-26 12:48:32+00:00
Resolved: 2020-07-01 21:51:11+00:00

##### [Description:]
When using any localized build with an overridden region, the search-config bucket is not synced with the main staging collection. The RS sync appears to be successful but the RS successful poll is not reflected in the correct update of search-config. 

With dump false all good, populates directly the expected staging main collection.

##### [Environments:]
Windows 10
Ubuntu 18.04
Mac 10.13.6

     reproducible using                  Nightly 78.0a1      2020-05-25
     *not reproducible* using            Nightly 78.0a1      2020-05-11 

##### [Pre-conditions:]
**user.js containing:**
user_pref("services.settings.server", "https://settings.stage.mozaws.net/v1");
user_pref("security.content.signature.root_hash", "DB:74:CE:58:E4:F9:D0:9E:E0:42:36:BE:6C:C5:C4:F6:6A:E7:74:7D:C0:21:42:7A:03:BC:2F:57:0C:8B:9B:90");
user_pref("services.settings.load_dump", true);
user_pref("services.settings.default_bucket", "main");
user_pref("browser.search.log", true);
+
user_pref("browser.search.region", "chosen_region");

**locale/region used to reproduce**
zn-cn/CN
en-US/US
wo/CN
ru/RU
es-ES/ES



##### [Steps:]
1. Download the localized build.
2. Create a new profile and add the specified user.js in the profile folder before start-up.
3. Start-up Firefox.
4. Check browser console for SearchEngineSelector: Search configuration updated remotely
5. Check about:config values for services.settings.last_update_seconds and services.settings.last_etag
6. Restart or leave idle for 5’ after either step 4 or step 5 are completed.


##### [Actual Results:]
Step 4 never shows the log for Search configuration updated remotely


services.settings.last_update_seconds: 1590480828  ~ 05/26/2020 @ 8:13am (UTC)
services.settings.last_etag :     "1590451272056"   ~ 05/26/2020 @ 12:01am (UTC)
browser console log: https://pastebin.com/BRBn8f9v

The loaded engines are the production main engines, not the staging main engines and the search config update is not happening no matter the wait time. 



##### [Expected Result:]
Even though it would be expected that the main production collection is initially first used since the dump only contains production main, at the RS sync, it would be expected that the collection gets updated and the user.js staging string is applied to acquire the staging main collection and engines to be updated to reflect the staging main.

##### [Note:]
dump false - issue is not reproducible since it will acquire the main staging engines @ start-up
Although this seems more like an RS issue rather than a search-config issue, these updates problems might be relevant to production environment updates, which QA cannot use to test and confirm the issue.

##### [Regression Range:]
   The issue doesn’t reproduce with Nightly 78.0a1 2020-05-11 (tried with two locales: es-ES and en-US), therefore it appears to be a regression.
    Unfortunately due to the fact that the preconditions are rather difficult to use with a moz-regression, I don’t think it is going to be reliable to try to get one.