Change Details

Parser::newFromAnon() in MW 1.47 should return `useParsoid` set to `true` by default; a new configuration variable `$wgUseLegacyParserByDefault` will allow opting out (until the next LTS release).

A new configuration variable `$wgUseLegacyParserByDefault` will allow opting out (until the next LTS release). Major components of this work are subtasks: 1. {T310512} * The way we do this with confidence is via {T310511}: building a testing infrastructure similar to the one we have with visualdiff and round-trip testing so that we can quantify metadata differences between legacy and parsoid. 2. {T393716} * Probably this will use the parallel parsing done in T310511 for comparisons, and then just selectively start using the Parsoid parse instead of the legacy parse (unless `$wgUseLegacyParserByDefault` is set). 3. {T370926} (optional) * We can meet our goals for MW 1.47 if UX message parsing is the *only* thing using the legacy parser, but ideally we should at least provide an experimental option to enable use of Parsoid for UX. (Maybe separate config than `$useLegacyParserByDefault`.) 4. {T420491} * This is a small code change but fixing CI is probably a much larger task: any test which relies on particular parser output will need to be updated. * The ParserMigration extension should still work, but in an opposite sense (allowing individual users to opt out of Parsoid). * Our mediawiki-config will have to be flipped, with individual wikis setting `$wgUseLegacyParserByDefault=true` (or maybe still via the ParserMigration extension).

Parser::newFromAnon() in MW 1.47 should return `useParsoid` set to `true` by default;A new configuration variable `$wgUseLegacyParserByDefault` will allow opting out (until the next LTS release). Major components of this work are subtasks: 1. {T310512} * The way we do this with confidence is via {T310511}: building a testing infrastructure similar to the one we have with visualdiff and round-trip testing so that we can quantify metadata differences between legacy and parsoid. 2. {T393716} * Probably this will use the parallel parsing done in T310511 for comparisons, and then just selectively start using the Parsoid parse instead of the legacy parse (unless `$wgUseLegacyParserByDefault` is set). 3. {T370926} (optional) * We can meet our goals for MW 1.47 if UX message parsing is the *only* thing using the legacy parser, but ideally we should at least provide an experimental option to enable use of Parsoid for UX. (Maybe separate config than `$useLegacyParserByDefault`.) 4. {T420491} * This is a small code change but fixing CI is probably a much larger task: any test which relies on particular parser output will need to be updated. * The ParserMigration extension should still work, but in an opposite sense (allowing individual users to opt out of Parsoid). * Our mediawiki-config will have to be flipped, a new configuration variablewith individual wikis setting `$wgUseLegacyParserByDefault` will allow opting out (until=true` (or maybe still via the next LTS releaseParserMigration extension).