Ensure errors.css is interpreted as UTF-8 encoding

What does this MR do and why?

Since gitlab-foss!19096 (merged), we've inlined the errors.css by directly including the Sprockets assets into the HAML. This worked fine as long as the CSS file remained as a plain ASCII file. However, the switch to the new CSS pipeline with !144479 (merged) appears to have introduced a single UTF-8 character. Since Sprockets loads the asset via File.binread (https://github.com/rails/sprockets/blob/d1dcf7075c468522e1cb6f93ae547d8d7fdcfbcb/lib/sprockets/asset.rb#L99), the contents of this UTF-8 file is forced as ASCII-8BIT. When this ASCII-8BIT string is combined with other UTF-8 characters, such as Chinese characters, the encoding fails with a 500 error: incompatible character encodings: ASCII-8BIT and UTF-8 (Encoding::CompatibilityError).

To work around this issue, we force the encoding to UTF-8 to ensure the error page can render.

Relates to gitlab-com/gl-infra/production#17627 (closed)

assigned to @stanhu

changed milestone to %16.10

added bugfunctional typebug labels

requested review from @engwan and @tachyons-gitlab

added 1 commit

• b936a1d3 - Ensure errors.css is interpreted as UTF-8 encoding

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	1 Warning
	You've made some app changes, but didn't add any tests. That's OK as long as you're refactoring existing code, but please consider adding any of the maintenancepipelines, maintenancerefactor, maintenanceworkflow, documentation, QA labels.

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I have confirmed locally that this fixes the problem.

approved this merge request

@engwan, thanks for approving this merge request.

This is the first time the merge request has been approved. To ensure we don't only run predictive pipelines, and we don't break master, a new pipeline will be started shortly.

Please wait for the pipeline to start before resolving this discussion and set auto-merge for the new pipeline. See merging a merge request for more details.

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mentioned in merge request !145355 (closed)

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mentioned in incident gitlab-com/gl-infra/production#17627 (closed)