A composite action that grew an input too many

A shared setup action across four repositories, with eleven inputs, of which one repository used a combination nobody had tested.

the inputs, and who used each:

  php-version        4 repositories
  run-integration    3
  coverage           2
  cache-key-suffix   1
  skip-composer      1
  extensions         1
  ini-values         1
  ...

five of eleven inputs exist for one caller each, which
is five conditionals in a shared file to avoid five
lines of duplication.

A shared abstraction with per-caller escape hatches is a worse arrangement than duplication, because the duplication is at least readable. The version that worked was three inputs in the shared action and a separate, simpler workflow for the repository that was genuinely different — which nobody proposes, because it feels like giving up.