RFR: 1726: PROGRESS_MARKER should be added before the CSR bot add CSR_UPDATE_MARKER

[Erik Joelsson]

On Thu, 22 Dec 2022 00:05:41 GMT, Zhao Song <zsong at openjdk.org> wrote:

> While testing [SKARA-1714](https://bugs.openjdk.org/browse/SKARA-1714) in this pull request (https://github.com/openjdk/playground/pull/112), we discovered that if a CSR issue already exists for a main issue and a pull request is then created for the main issue, the CSR and PR bots become stuck in an endless loop and are unable to update the pull request body. 
> 
> After further investigation, we determined that the cause of this issue is that the CSR bot checks for the presence of the CSR_UPDATE_MARKER in the pull request body before adding it, but first checks for the PROGRESS_MARKER. However, when the CSR bot's pullRequestWorkItem runs for the first time, it is likely that the PR bot's CheckWorkItem has not yet run, resulting in the absence of the PROGRESS_MARKER in the pull request body. In this case, the CSR bot continues to add the CSR_UPDATE_MARKER, while the PR bot attempts to update the pull request body but finds that it has been recently updated and therefore gives up on the update. 
> 
> The correct fix is to only add CSR_UPDATE_MARKER if we find a PROGRESS_MARKER.

Marked as reviewed by erikj (Lead).

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PR: https://git.openjdk.org/skara/pull/1447