On Tue, Jan 19, 2021 at 04:27:56PM +0000, David Edmondson wrote: > On Tuesday, 2021-01-19 at 10:20:56 -05, Eduardo Habkost wrote: > > > Hi, > > > > Thanks for the patch. Getting rid of special -feature/+feature > > behavior was in our TODO list for a long time. > > > > On Tue, Jan 19, 2021 at 02:22:06PM +0000, David Edmondson wrote: > >> "Minus" features are applied after "plus" features, so ensure that a > >> later "plus" feature causes an earlier "minus" feature to be removed. > >> > >> This has no effect on the existing "-feature,feature=on" backward > >> compatibility code (which warns and turns the feature off). > > > > If we are changing behavior, why not change behavior of > > "-feature,feature=on" at the same time? This would allow us to > > get rid of plus_features/minus_features completely and just make > > +feature/-feature synonyms to feature=on/feature=off. > > Okay, I'll do that. > > Given that there have been warnings associated with > "-feature,feature=on" for a while, changing that behaviour seems > acceptable. > > Would the same be true for changing "-feature,+feature"? (i.e. what this > patch does) Really: can this just be changed, or does there have to be > some period where the behaviour stays the same with a warning?
I actually expected warnings to be triggered when using "-feature,+feature" as well. If we were not generating warnings for that case, it will need more careful evaluation, just to be sure it's safe. Igor, do you remember the details here? -- Eduardo
