
Extensions that define any custom GUCs should call EmitWarningsOnPlaceholders after doing so, to help catch misspellings. Many of our contrib modules hadn't gotten the memo on that, though. Also add such calls to src/test/modules extensions that have GUCs. While these aren't really user-facing, they should illustrate good practice not faulty practice. Shinya Kato Discussion: https://postgr.es/m/524fa2c0a34f34b68fbfa90d0760d515@oss.nttdata.com