On Mon, 2019-11-25 at 20:39 +0200, Joonas Niilola wrote: > Hey, > > > On 11/25/19 7:38 PM, Michał Górny wrote: > > Hi, > > > > TL;DR: should we depend on setuptools by default? Alternatively, should > > we add distutils_enable_setuptools API to provide at least partial > > validity checks. > > > > > > The problem > > =========== > > The vast majority of Python packages nowadays uses setuptools as their > > build system. According to a cheap grep, 1633 out of 2415 packages > > using distutils-r1 depends on it -- and I suspect the vast majority of > > those that do not are simply missing the dependency. > > Truthfully I thought distutils already (B)DEPENDed on setuptools, so at > least I've left it out "on purpose". I was recently made aware it > doesn't. No bug reports are made about it, so I think it's safe to > assume setuptools is already present in every system?
Yes, we do get bug reports about it occassionally. > > > > Are there valid cases for not using setuptools? Notably, packages > > needed to bootstrap setuptools aren't using it. Plus some simple > > packages that really don't need its features. > > > > There are also packages that use setuptools but have distutils fallback. > > We don't like them because switching between build systems involves file > > <-> directory replacement that isn't handled cleanly by our package > > managers. Therefore, we want to always force one build system in them. > > > > The setuptools dependency is so common it's easy to miss. Notably, it's > > a prerequisite of specifying package dependencies, so it's normally not > > listed in dependencies. > > > > Finally, while most of the time setuptools is just BDEPEND, there are > > cases when it's RDEPEND as well. The most common is the use > > of entry_points -- and again, upstreams don't mention it explicitly. > > > > All that considered, I think we should work on providing a better API > > for depending on setuptools, to reduce the number of missing > > dependencies and make it possible to automatically test for them > > (reminder: PMS doesn't permit inspecting *DEPEND). > > > > > > Variant 1: automatic dependency on setuptools > > ============================================= > > Basically, we add a new trinary pre-inherit variable: > > > > DISTUTILS_USE_SETUPTOOLS=no > > -> no deps > > DISTUTILS_USE_SETUPTOOLS=bdepend > > -> add to BDEPEND (the default) > > DISTUTILS_USE_SETUPTOOLS=rdepend > > -> add to BDEPEND+RDEPEND > > > > This is roughly 'erring on the safe side'. The default will work for > > the majority of packages. We will have to disable it for setuptools > > bootstrap deps, and devs will be able to adjust it to correct values > > as they update ebuilds. For the time being, existing *DEPEND > > on setuptools will avoid breaking stuff. > > > > This will also enable me to add extra QA checks to esetup.py. It should > > be able to reasonably detect incorrect value and report it. This will > > imply some 'false positives' for packages that use the old method of > > specifying setuptools in RDEPEND but that's a minor hassle. > > > > Pros: > > - works out of the box for the majority of packages > > - enables full-range QA checking > > > > Cons: > > - pre-inherit variable > > - some (harmless) false positives on existing packages > > I'm a fan of this solution, unless it causes a lot of new CI noise. I > think people are getting fed up with recent changes already, starting to > ignore whatever CI bot says, unless it's fatal. > > No harm in double-defining setuptools in BDEPEND right...? (via eclass > and ebuild) Yes, double defining is fine. > > > > > > Variant 2: distutils_enable_setuptools > > ====================================== > > The alternative method is to add another function > > to the distutils_enable* series: > > > > distutils_enable_setuptools [-r] > > > > The basic form adds it to BDEPEND, -r B+RDEPEND. Of course, no dep is > > present by default. The main difference from setting deps explicitly is > > that it permits us to do a minimal QA check between pure BDEPEND > > and B+RDEPEND for now. > > > > When all ebuilds are migrated from explicit dependencies to this method, > > we can also start detecting missing deps completely. However, that > > presumes we require using this function rather than explicit deps. > > > > Pros: > > - no pre-inherit variables > > > > Cons: > > - only partial QA check possible for the time being > > - requires migrating all ebuilds long-term > > I don't like this at this point. This would just bring unwanted noise > and lots of editing in ebuilds. V1 and V3 are better IMHO. This could be > implemented in distutils-r2.eclass, though. > > > > > > Variant 3: leave as-is, add minimal install-qa-check.d > > ====================================================== > > We can just continue adding deps manually, and add a minimal install-qa- > > check.d that greps installed scripts for entry_points usage. This will > > let us detect missing RDEPEND on setuptools but not BDEPEND. > > > > Pros: > > - no changes to ebuilds > > > > Cons: > > - only partial QA check possible > > The old way, is also good. > > > > > > WDYT? > > ===== > > Both options have their pros and cons. I think V1 is the best since it > > avoids a common mistake, and gives full range QA check. It also doesn't > > interfere with existing deps. V2 neatly fits into the recent series but > > still requires users to remember to call it, and we can't report missing > > calls until we clean up all ebuilds. V3 provides only minimal QA > > improvement without changing the eclass. > > > > WDYT? Do you have any other ideas? > > As I said, I don't even know how one ends up with a system without > setuptools, so I don't view this "superimportant". Still I like your > suggestions 1 & 3 in handling it in future. However if you're going to > implement CI checks with this, I don't believe the timing is right > currently. > 1. If you have no packages with RDEPEND on setuptools and some --with- bdeps setting, --depclean can kill it. 2. Early after install. 3. On tinderbox, if no dep pulled it in. -- Best regards, Michał Górny
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