[Python-Dev] magic in setuptools (Was: setuptools in the stdlib) (original) (raw)

"Martin v. Löwis" martin at v.loewis.de
Thu Apr 20 21:53:00 CEST 2006

Anthony Baxter wrote:

4. .egg files. -1 As far as I understand it, an egg file is just a zipimport format zip file with some additional metadata. You can also install the egg files in an unpacked way, if you prefer that. I don't understand the objection here - it's no better or worse than countless packages in site-packages, and if it gives us multiple versions of the same code, all the better.

It is worse: each .egg file makes an additional sys.path entry (if I understand correctly); every import statement will traverse every every package. I'm not sure precisely how all this works, but I wouldn't be surprised if the zip directory is read over and over again. Compare that to countless packages in site-packages: "import foo" will just look for foo.py, foo.so, and the directory foo.

I understand there is a second API to importing, some kind of "require()" call. I consider that even worse: it obsoletes the language's mechanism for modules, and defines its own modularization.

However, this isn't really my objection to .egg files. I dislike them because they compete with platform packages: .rpm, .msi, .deb. Package authors will refuse to produce them, putting the burden of package maintenance (what packages are installed, what are their dependencies, when should I remove a package) onto the the end user/system administrator.

Regards, Martin

More information about the Python-Dev mailing list