develop mode does not respect src structure

Originally reported by: marscher (Bitbucket: marscher, GitHub: marscher)

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Assume you have project with a src folder:

#!python

root/
root/setup.py
root/src/my_pkg/__init__.py
....

in setup.py one have mapped the src folder, so it can be found during installation.

#!python

setup( ....
   package_dir = { 'my_pkg' : 'src' } 
)

If one tries to install an egg link to the pkg via setup.py develop, this mapping is happily ignored. I'am not sure, if this is an issue either with setuptools or distutils. Symlinking my_pkg to the root fixes the problem.

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• Bitbucket: https://bitbucket.org/pypa/setuptools/issue/230

Original comment by jaraco (Bitbucket: jaraco, GitHub: jaraco):

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This is a long-standing issue, originally reported as Distribute 177. If you read the background there, you'll see that the problem doesn't have an obvious general solution.

Edit: Distribute 177 is here.

Original comment by jaraco (Bitbucket: jaraco, GitHub: jaraco):

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Issue #276 was marked as a duplicate of this issue.

Original comment by mgedmin (Bitbucket: mgedmin, GitHub: mgedmin):

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@marscher: your setup.py looks wrong. AFAIU it should say

package_dir = { 'my_pkg' : 'src/my_pkg' }

A simple workaround exists, as long as the package name matches the directory name: strip the last name from both sides of the mapping and use

package_dir = { '' : 'src' }

@jaraco: perhaps it'd be good to have 'python setup.py develop' fail with an error message instead of resulting in a broken .pth file? As long as it doesn't break the workaround, which is widely used in thousands of packages, of course.

I think it should be possible to solve this for all cases where the directory names in the source tree match package names, with a little bit of programming.

(EDIT: updated @-mentions to use people's bitbucket usernames rather than first names. Sorry unrelated people who were probably pinged by mail, I didn't know that bitbucket actually parsed @-mentions in comments!)

Original comment by jaraco (Bitbucket: jaraco, GitHub: jaraco):

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Issue #463 was marked as a duplicate of this issue.

[jaraco]

@RonnyPfannschmidt has suggested a few options:

• symlink the packages during develop install
• create shim file
• create meta import hook

All of these run into challenges thinking about the total workflow (how are they registered/uninstalled).

If someone could put together a routine or package that demonstrates a technique for installing such a hook, then we can work to devise a workflow around it to use within the develop command and installers.

[RonnyPfannschmidt]

i documented some of it in https://mail.python.org/pipermail/distutils-sig/2017-September/031498.html

i made a prior implementation in https://github.com/RonnyPfannschmidt/gumby_elf/blob/03391bdf0cc66faaa2a5e034769e557c31974fd9/src/packing.py#L34-L43

i believe the best prospect is building/installing the dist info alongside a bootstrapped and a altered record file