Hi Conal.
Thanks for the reply! Note that I get this message even running 'cabal install' a second time after changing nothing. Is that scenario an example of what you mean by a "potentially dangerous cabal invocation"?
The check currently is entirely ad-hoc. Any reinstallation of an existing package triggers the warning. There's no hash comparison.
I've been unable to avoid this error message by any other means that (a) 'ghc-pkg unregister <package>' or (b) '--force-reinstall'. So far, '--solver=modular' hasn't helped. So I'm hoping for something less aggressive. In particular, in case nothing has changed, I want 'cabal install' to succeed (exit code 0) so that my automated build & install & release processes will continue rather than get stopped.
The message appears, but building should work, with --force-reinstall and no --dry-run. Can you confirm that you've tried that? Cheers, Andres