Would be nice to be able to install add-ons from Builder into Nightly without having to add the extensions.checkCompatibility.nightly pref turned on. The SDK bumped maxVersion to 8.0a1 in https://github.com/mozilla/addon-sdk/commit/e932b1995f77d4fb8bd313f4b165b76a99d0a97a but it should be safe to allow 8.0a1 to install SDK 1.0 extensions built from the Builder, in my opinion.
install.rdf is created during xpi creation - we use SDK for that
Indeed. It would seem that the SDK 1.0 has its max version below 8. The only way to fix that would be to release an SDK 1.0.1, or something similar.
The next Firefox cycle in mid-August would mean that SDK 1.0 and Builder would only be marked compatible with the release version of Firefox. (Even the beta channel builds wouldn't work, I think, since 7.0 is > 7.0a1) And according to Myk's proposed release process, the 1.1 SDK won't be out until mid-September. Once Jetpack gets into the proposed 6-week cycle, this shouldn't be a problem since the next SDK release will be coming out prior to the next Firefox release, but the 1.1 timeframe is off a bit. Myk said he was open to releasing a 1.0.1 off of the 1.0 tag to include a maxVersion bump before that happens.
The Daves and I talked about this during today's triage session. Our plan is for each SDK stable release to support the Firefox stable release that is in beta at the time the SDK release ships. So SDK 1.1, which ships September 13, will support Firefox 7, which ships September 27; and SDK 1.2, which ships October 25, will support Firefox 8, which ships November 8. The SDK 1.0 schedule is a little different, since it shipped alongside Firefox 5 but also supports Firefox 6. Nevertheless, the key similarity is that all these SDK stable releases support stable releases of Firefox, not nightly or aurora builds. Our solution for SDK users who want to test with nightly and aurora builds is to use a development version of the SDK, i.e. to pull the SDK from the development branch of the source code repository, which will be updated to stay compatible with the latest version of Firefox in its central branch (from which its nightlies are built). And that seems better than spinning minor updates to stable releases such as an SDK 1.0.1, since nightlies can break the SDK at any time, so it isn't particularly safe to say that the latest SDK stable release supports the unstable Firefox nightly builds. So we have decided not to release SDK 1.0.1 that claims to support Firefox nightly builds. However, we support Firefox nighly builds on trunk and will continue to do so. If Builder were to add support for an "SDK nightly build" that it downloaded once per day, and addons could specify that they want to use the latest SDK nightly instead of a particular SDK stable release, then they could support the latest Firefox builds (at some cost in SDK stability). Food for thought!