Sentry reports on Multiple Reloads of Governance Actions Page

[sentry-io]

Context

• The system throws an exception user error (mzero) during a GET request to governance action list while handling concurrent fetches triggered by page reloads.

Sentry Issue: GOVTOOL-BACKEND-J3

Exception user error (mzero) while handling request Request {requestMethod = "GET", httpVersion = HTTP/1.1, rawPathInfo = "/proposal/list", rawQueryString = "?page=0&pageSize=7&type[]=ParameterChange", requestHeaders = [("Host","dev-sanchonet.govtool.byron.network"),("User-Agent","Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"),("Accept","application/json, text/plain, */*"),("Accept-Encoding","gzip, deflate, br, zstd"),("Accept-Language","en,en-GB;q=0.9,en-US;q=0.8"),("Authorization","Basic Z292dG9vbDpBOEZ4RE1ud0dvY0RlS1FS"),("Cookie","_ga=GA1.1.1789033277.1724837231; ajs_anonymous_id=%2295851626-6b6d-42ce-a52b-0dda5afa3b62%22; _pk_id.1.444d=e800422ca3c50774.1732858397.; _ga_HEZ7H5YRZC=GS1.1.1732883354.83.1.1732885659.0.0.0"),("Priority","u=1, i"),("Referer","https://dev-sanchonet.govtool.byron.network/governance_actions"),("Sec-Ch-Ua","\"Google Chrome\";v=\"131\", \"Chromium\";v=\"131\", \"Not_A Brand\";v=\"24\""),("Sec-Ch-Ua-Mobile","?0"),("Sec-Ch-Ua-Platform","\"Linux\""),("Sec-Fetch-Dest","empty"),("Sec-Fetch-Mode","cors"),("Sec-Fetch-Site","same-origin"),("X-Forwarded-For","113.199.224.235"),("X-Forwarded-Host","dev-sanchonet.govtool.byron.network"),("X-Forwarded-Port","443"),("X-Forwarded-Prefix","/api"),("X-Forwarded-Proto","https"),("X-Forwarded-Server","1bc69d9655d0"),("X-Real-Ip","113.199.224.235")], isSecure = False, remoteHost = 172.20.0.3:57170, pathInfo = ["proposal","list"], queryString = [("page",Just "0"),("pageSize",Just "7"),("type[]",Just "ParameterChange")], requestBody = <IO ByteString>, vault = <Vault>, requestBodyLength = KnownLength 0, requestHeaderHost = Just "dev-sanchonet.govtool.byron.network", requestHeaderRange = Nothing}

Steps to Reproduce

1. Navigate to the Governance Actions page.
2. Reload the page while the proposal list is still in the loading (fetching) state.
3. Observe that the error is logged in Sentry during subsequent API requests.

https://www.loom.com/share/5b90454607734bafa7f68aa2040afe51?sid=ba070593-0712-459c-b8ae-bae692f73da3

[placek]

The function listProposals is responsible for fetching and returning a paginated list of proposals with filtering and sorting applied. The error user error (mzero) could arise here if certain conditions aren't properly accounted for or if there are unexpected behaviors in intermediate computations. Below are potential areas to debug and resolve the issue:

1. Empty or missing Data:

If getVotes, cacheRequest, or Proposal.listProposals return unexpected Nothing or invalid data, downstream operations could fail.

2. Improper pagination:

If page or pageSize result in an invalid range (e.g., take or drop operating on an empty list), mzero could be triggered in computations expecting non-empty results.

3. My guess: Unhandled MonadFailures:

Operations like list lookups, mapping, or pattern matching in mapSortAndFilterProposals or filter may implicitly use MonadFail, leading to mzero when assumptions are violated.

[sentry-io]

Reported on current dev today at (https://dev-sanchonet.govtool.byron.network/connected/governance_actions)

Sentry Issue: GOVTOOL-BACKEND-J3

CC: @MSzalowski @bosko-m