Post-creation script option

[jamestelfer]

There's a variety of actions that may be desired after creating a PR: changing assignees/reviewers dynamically, adding to a project, dynamic tagging, updating links in the PR body, ... the potential list is quite long.

Instead of trying to make all these things work, we could instead add a postExecuteSuccessful script hook to the configuration. This would be executed in the context of the repository after a successful script run, and after the pull/merge request has been created.

A number of details can be passed as environment variables to the hook script, including:

• the repository REPOSITORY
• the PR/MR URL: REQUEST_URL
• the PR/MR number: REQUEST_NUMBER
• the process result: REQUEST_STATUS (CREATED/REPLACED/SKIPPED) -- if the branch was created, replaced or if it was skipped because one already existed.

Given the repository and PR number, it's relatively straightforwards to use the GitHub CLI to modify tags, add comments or change the PR description (say, annotating it with PR content-specific data for example).

Good idea/bad idea?

I've been using this in conjunction with GitHub projects, so after a PR is created I run a script to add the PR to a project, and then another to tag the PR with metadata that's specific to the repository. Conceivably I could switch to maintain issues in JIRA instead using this approach (I could, regardless whether I wanted to...).