[wleeaf]

Description
Negotiate::matchTypes() splits each value on / and reads the subtype without checking that one exists. So media() throws ErrorException: Undefined array key 1 when the Accept header holds a value without a subtype, such as json, or an empty list element (Accept: , text/html). That value is compared with every supported type before the next header value is reached, which means the exception happens even when a later value in the header would match.

matchTypes() now returns false when either value has no /. A value like that is not a media type, so Accept: json, application/json now resolves to application/json. Headers that were already handled return the same results.

testBestMatchIgnoresMediaRangesWithoutSubtype in tests/system/HTTP/NegotiateTest.php covers both inputs. Without the change it fails with ErrorException: Undefined array key 1. The v4.7.6 changelog has a Bugs Fixed entry.

tests/system/HTTP/ passes. php-cs-fixer, PHPStan and Rector (dry run) report nothing for the changed files.

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value (without duplication)
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[carson-codeigniter4]

Hi there, @wleeaf! 👋

Thank you for sending this PR!

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