HeaderMatch: pass all headers into strategy block

[samford]

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This modifies livecheck's HeaderMatch strategy to allow strategy blocks to use an all_headers argument to receive the original array of response headers rather than a merged hash that only includes the last instance of a given header. Over the years, we've encountered a few checks where a server makes multiple redirections (i.e., there are multiple responses with a Location header) but we need to target a Location header that isn't the last occurrence. This hasn't been possible due to the merged_headers setup, so we've simply worked around it.

We recently ran into this shortcoming again in homebrew-cask but there isn't a way to work around it this time, so this is now strictly necessary. This implementation borrows from my prior art in the Sparkle strategy, where the name of the first argument to a strategy block is strictly enforced and the name dictates what value is provided. I've ensured that all HeaderMatch strategy blocks in core/cask use a headers argument, so they will continue working as expected.

[Copilot]

Pull request overview

This PR updates the livecheck HeaderMatch strategy so strategy blocks can opt into receiving either a merged headers hash (headers) or the full array of per-response headers (all_headers), enabling version extraction from non-final redirect headers.

Changes:

• Change HeaderMatch.versions_from_content to accept an array of response header hashes and provide either merged headers or all headers to the strategy block based on the first block argument name.
• Update HeaderMatch.find_versions to pass the full headers array through to versions_from_content.
• Expand/update HeaderMatch strategy specs to cover the new all_headers behavior and error handling.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
Library/Homebrew/livecheck/strategy/header_match.rb	Adjusts strategy logic to pass full headers array or merged hash into the strategy block and updates header parsing flow.
Library/Homebrew/test/livecheck/strategy/header_match_spec.rb	Updates tests for the new array-of-headers input and adds coverage for all_headers block behavior and signature validation.

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[MikeMcQuaid]

Thanks!