[tomaj]

PHP 8.6 appends the position to JSON error messages: Syntax error became Syntax error near location 1:12. Two MessageSerializerTest tests compared the exact text, so the PHP 8.6 job failed.

Audit

• src/ does not depend on the text. MessageSerializer only passes JsonException::getMessage() through into the SerializeException message and sets the JSON_ERROR_* code as the exception code. No logic compares messages.
• Full test suite on PHP 8.6.0RC4 (php:8.6-rc-cli, failOnDeprecation/failOnNotice, error_reporting=-1): after this change the only failures came from extensions missing in the local image (redis, pcntl). There were no deprecations, notices or other 8.6 failures. The full run with every extension and broker is the CI PHP 8.6 job.
• composer.json php constraint does not block 8.6.

Changes

• Tests: the expected JSON error text comes from the running PHP (jsonError() helper), and the exact assertions stay in place. testInvalidJsonKeepsTheJsonExceptionAsPrevious also asserts the invalid JSON (Syntax error prefix next to the JSON_ERROR_SYNTAX code.
• UPGRADE-6.0.md: notes that the text in parentheses after invalid JSON depends on the PHP version, and that code should match the JSON_ERROR_* code instead. The EN and SK docs only show <error>, so they need no change.
• CHANGELOG 6.0.0 Fixed entry.
• The PHP 8.6 job stays continue-on-error because 8.6 is not GA yet.

Review log

1. Round 1: assertions inside the static data-provider helper were moved out. The helper now only returns the text, and the prefix and code assertions live in a test.
2. Round 2: checked docs for quoted error text (only UPGRADE-6.0.md has it, EN/SK docs use <error>), the CHANGELOG placement and the commit metadata. Found nothing.
3. Round 3: full diff again on 8.4 and 8.6. Found nothing.

Verification

• MessageSerializerTest passes on PHP 8.4.26 and 8.6.0RC4 (it failed on 8.6 before this change)
• PHPStan, php-cs-fixer and Rector are clean
• No src/ changes, so Infection has no changed lines to mutate (CI Infection job)
• CI is green, including PHP 8.6

[coveralls]

Coverage Report for CI Build 40215322223

Coverage remained the same at 99.283%

Details

• Coverage remained the same as the base build.
• Patch coverage: No coverable lines changed in this PR.
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

---

Coverage Stats

Relevant Lines:	697
Covered Lines:	692
Line Coverage:	99.28%
Coverage Strength:	23.4 hits per line

---

💛 - Coveralls