On Mon, Jan 16, 2023 at 11:54:46AM +0900, Michael Paquier wrote: > On Sun, Jan 15, 2023 at 07:56:25PM -0600, Justin Pryzby wrote: > > On Mon, Jan 16, 2023 at 10:28:50AM +0900, Michael Paquier wrote: > >> The functions changed by 0001 are cfopen[_write](), > >> AllocateCompressor() and ReadDataFromArchive(). Why is it a good idea > >> to change these interfaces which basically exist to handle inputs? > > > > I changed to pass pg_compress_specification as a pointer, since that's > > the usual convention for structs, as followed by the existing uses of > > pg_compress_specification. > > Okay, but what do we gain here? It seems to me that this introduces > the risk that a careless change in one of the internal routines if > they change slight;ly compress_spec, hence impacting any of their > callers? Or is that fixing an actual bug (except if I am missing your > point, that does not seem to be the case)?
To circle back to this: I was not saying there's any bug. The proposed change was only to follow normal and existing normal conventions for passing structs. It could also be a pointer to const. It's fine with me if you say that it's intentional how it's written already. > >> Is there some benefit in changing compression_spec within the > >> internals of these routines before going back one layer down to their > >> callers? Changing the compression_spec on-the-fly in these internal > >> paths could be risky, actually, no? > > > > I think what you're saying is that if the spec is passed as a pointer, > > then the called functions shouldn't set spec->algorithm=something. > > Yes. HEAD makes sure of that, 0001 would not prevent that. So I am a > bit confused in seeing how this is a benefit.
