> On Jan 22, 2016, at 1:46 PM, Nathaniel Smith <n...@pobox.com> wrote: > > On Jan 22, 2016 10:11 AM, "Donald Stufft" <don...@stufft.io > <mailto:don...@stufft.io>> wrote: > > > > PEP 376 added a file to the .dist-info directory called "INSTALLER" which > > was > > supposed to be: > > > > This option is the name of the tool used to invoke the installation. > > > > However, nothing has really ever implemented it and it's gone largely > > ignored > > until just recently pip 8.0 started writing the INSTALLER file into the > > metadata directories with a value of "pip". > > > > I'd like to propose adding a special cased value to add to the installer > > file > > that will tell projects like pip that this particular installed thing is > > being > > managed by someone else, and we should keep our hands off of it. According > > to > > PEP 376 the supported values for this file are r"[a-z0-9_-.]", however I > > think > > since nobody has ever implemented it, we could expand that so that it so you > > can also have a special value, of "dpkg (system)" or maybe that's not worth > > it > > and we could just have "system" as a special value. > > I think we want more than just "system", because the same user could have > some packages managed by dpkg and some by conda, both of which have their own > dependency resolution mechanisms that are outside pip's and could get broken > if pip removes stuff willy-nilly. And when pip errors out, you want to be > able to explain to the user "this package is managed by conda, and using pip > on it may break your conda setup..." versus "this package is managed by > Debian, and using pip on it may break your Debian setup...". > > (Actually I'm not sure what the status these days is of mixing pip and conda > -- they've gotten somewhat better at handling it. Is the proposed behavior in > pip when it sees this flag something that distribution maintainers have asked > for? Are they present in this thread?) > >
Yea, that’s why I thought about dpkg (system) or system(Debian) or something. The main reason I can think of for preferring “system” is if we don’t want to change the valid characters for a value in this file. Then you can have system(Debian) and system(Conda) and everything will work just fine. > > The benefit of doing this, is that with a special value in that file that > > says > > "this file belongs to the OS", then pip could start looking for that file > > and > > require a --force flag before it modifies any files belonging to that > > project. > > Then distributors like Debian, Fedora, etc could simply write out the > > INSTALLER > > file with the correct value, and pip would start to respect their files by > > default. > > I'd like a little more clarity on exactly what circumstances justify setting > this flag. If I write a new python package manager, then should I set this > flag on all my packages because I don't trust anyone else to get things > right? :-) > > Maybe the relevant thing is what I said above, that there is some system > tracking these files that is not using the dist-info directory as its > source-of-truth about what's installed, dependencies, etc. > > -n > ----------------- Donald Stufft PGP: 0x6E3CBCE93372DCFA // 7C6B 7C5D 5E2B 6356 A926 F04F 6E3C BCE9 3372 DCFA
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