This change refactors how issue title changes from gitlab events are
detected, fixing an issue (due to upstream changing the format of the
event body from markdown-esque to html), and improving on error
handling.

The error boiled down to a change in the issue title format. Gitlab
changed this on April 17 2025 with the release of version 17.11 [0],
although the only place a reference to this change exists is in the
changelog [1], which is not linked to from the releases page.

To account for the potential future in which other fields need to be
parsed in this way, an internal parser library was introduced at
`//bridge/gitlab/parser:parser.go` with initial support for parsing
title change messages.

An issue was opened with the Gitlab team discussing the fact that this
was a breaking change [2]. This may lead to moving title changes (or
maybe all changes) to `resource_*_events`, which would likely provide a
smoother experience for our use case.

Debugging this issue surfaced a few pain points with this bridge:

- Errors are few and far between, and when they do exist and are
  managed, they are often not propagated, often existing as simple
  `fmt.Printf` calls
- Inconsistent and uninformative logging structure when there _are_
  errors, leading to challenges in debugging unexpected behavior
- Fragility: we are parsing random text from event fields (for title
  changes and more). This will likely lead to future breakage should
  Gitlab change the format of other fields. Ideally, the gitlab SDK
  would start classifying notes and have fields like `type`, `old`,
  `new`... but this is unlikely to happen in the short term

[0]: https://about.gitlab.com/releases/2025/04/17/gitlab-17-11-released/
[1]: https://gitlab.com/gitlab-org/gitlab/-/commit/b3e1fdcf45f8b18110a2f5217b9964a11616d316#ab09011fa121d0a2bb9fa4ca76094f2482b902b7_5_232
[2]: https://gitlab.com/gitlab-org/gitlab/-/issues/536827

Closes: #1367
Change-Id: I3bd7fa1c39a9e4dd2176d6e482e30ab68965f6e7

sudoforge marked this pull request as ready for review

sudoforge deleted the I3bd7fa1c39a9e4dd2176d6e482e30ab68965f6e7 branch