Linking PRs to issues does not always work

[mnonnenmacher]

When referencing an issue in a commit message, GitHub should automatically link the PR and issue if the PR targets the main branch:
https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue

For some reason this does not always work in this repository, for example:

PR #863 was automatically linked to #720 and the issue was closed when the PR was merged.
PR #176 referenced #174 in a commit message, but the automatic linking did not work and the issue was not closed when the PR was merged.

To me it is completely unclear why the linking sometimes does not work and I could not recognize any pattern. The only restricition from the docs is:

However, if the PR's base is any other branch, then these keywords are ignored, no links are created and merging the PR has no effect on the issues.

But all affected PRs did target the main branch.

If you see this issue happening again, please add the affected PR and issue numbers in a comment, maybe collecting them helps to find the root cause.

[Etsija]

My latest case from yesterday:

• there was an issue Remove the spinner from page index edit fields #835 and I used GitHub UI to create a feature branch for it to our fork of the ORT Server
• made the PR ui: Remove the unnecessary spinners from table pagination component #864 which included this commit which has "Resolves Remove the spinner from page index edit fields #835"
• the PR ui: Remove the unnecessary spinners from table pagination component #864 was merged, but no auto-closing of the issue Remove the spinner from page index edit fields #835 happened; I needed to close it manually today

As a side note: when you create a feature branch out of an issue using GitHub, GitHub hints something along the lines of "merging this branch may subsequently close this issue". To my experience, it never does, and I don't know if it's because I always create the branch to doubleopen fork of the repository, not to the core repository.

[mnonnenmacher]

Linking did not work for #406.

[Etsija]

#887 closed #833. "Defaults..." text is in the description of #887, and I created a branch out of #833. GitHub also showed me this in the PR #887:

[Etsija]

#892 didn't close #890. Thinking that when the "Resolves..." is in the commit message , as in this PR, not on the top-level PR description, GitHub doesn't actually link the PR to the issue properly for auto-closing.

[sschuberth]

#986 did not auto-close.

[mnonnenmacher]

#605 did not auto-close.