By default this uses the existing ContentHandler::serializeContent() and
::unserializeContent() methods. But in cases where existing PHP
serialization preserved fields that ::serializeContent() did not,
provide an additional ContentHandler::serializeContentToJsonArray()
and ContentHandler::deserializeContentFromJsonArray() methods which
can be used. Use these in WikitextContentHandler to preserve the
PST flags.
Added test cases and a ContentSerializationTestTrait to make it
easy to ensure forward- and backward-compatibility in accord with
https://www.mediawiki.org/wiki/Manual:Parser_cache/Serialization_compatibility
The new JsonCodecable codec will be used to improve PageEditStashContent
serialization, which no longer has to PHP-serialize its Content object.
New test case added demonstrating compatibility.
Bug: T264389
Bug: T161647
Change-Id: I544625136088164561b9169a63aed7450cce82f5
(cherry picked from commit 21576d6c1893079777a1a51d0f81c4941c58e376)
df9756b9a1