beyond top level package error in relative import

Question

It seems there are already quite some questions here about relative import in python 3  but after going through many of them I still didn t find the answer for my issue   so here is the question    I have a package shown below  package       init   py    A          init   py       foo py    test A          init   py       test py   and I have a single line in test py   from   A import foo   now  I am in the folder of package  and I run   python -m test A test   I got message   ValueError  attempted relative import beyond top-level package    but if I am in the parent folder of package  e g   I run   cd    python -m package test A test   everything is fine    Now my question is   when I am in the folder of package  and I run the module inside the test A sub-package as test A test  based on my understanding    A goes up only one level  which is still within the package folder  why it gives message saying beyond top-level package  What is exactly the reason that causes this error message

User · Answer

This is very tricky in Python  I ll first comment on why you re having that problem and then I will mention two possible solutions   What s going on   You must take this paragraph from the Python documentation into consideration   Note that relative imports are based on the name of the current module  Since the name of the main module is always  quot main quot   modules intended for use as the main module of a Python application must always use absolute imports   And also the following from PEP 328   Relative imports use a module s name attribute to determine that module s position in the package hierarchy  If the module s name does not contain any package information  e g  it is set to  main   then relative imports are resolved as if the module were a top level module  regardless of where the module is actually located on the file system   Relative imports work from the filename    name   attribute   which can take two values   It s the filename  preceded by the folder strucutre  separated by dots  For eg  package test A test Here Python knows the parent directories  before test comes test A and then package  So you can use the dot notation for relative import      package test A test py from   A import foo  You can then have like a root file in the root directory which calls test py     root py from package test A import test   When you run the module  test py  directly  it becomes the entry point to the program   so   name        main    The filename has no indication of the directory structure  so Python doesn t know how to go up in the directory  For Python  test py becomes the top-level script  there is nothing above it  That s why you cannot use relative import     Possible Solutions  A  One way to solve this is to have a root file  in the root directory  which calls the modules packages  like this    root py imports test py   entry point    name        main     test py  relative  imports foo py  foo py says the module has been imported   The output is  package A foo has been imported Module s name is   package test A test  B  If you want to execute the code as a module and not as a top-level script  you can try this from the command line  python -m package test A test  Any suggestions are welcomed  You should also check  Relative imports for the billionth time   specially BrenBarn s answer

User · Answer

In my humble opinion  I understand this question in this way    CASE 1  When you start an absolute-import like  python -m test A test   or  import test A test   or   from test A import test   you re actually setting the import-anchor to be test A  in other word  top-level package is test A   So  when we have test py do from   A import xxx  you are escaping from the anchor  and Python does not allow this    CASE 2  When you do  python -m package test A test   or  from package test A import test   your anchor becomes package  so package test A test py doing from   A import xxx does not escape the anchor still inside package folder   and Python happily accepts this   In short    Absolute-import changes current anchor   redefines what is the top-level package    Relative-import does not change the anchor but confines to it    Furthermore  we can use full-qualified module name FQMN  to inspect this problem   Check FQMN in each case     CASE2  test   name     package test A test  CASE1  test   name     test A test   So  for CASE2  an from    import xxx will result in a new module with FQMN package xxx  which is acceptable   While for CASE1  the    from within from    import xxx will jump out of the starting node anchor  of test A  and this is NOT allowed by Python

User · Answer

import sys sys path append         Adds higher directory to python modules path    Try this  Worked for me

User · Answer

This one didn t work for me as I m using Django 2 1 3  import sys sys path append  quot    quot     Adds higher directory to python modules path   I opted for a custom solution where I added a command to the server startup script to copy my shared script into the django  app  that needed the shared python script  It s not ideal but as I m only developing a personal website  it fit the bill for me  I will post here again if I can find the django way of sharing code between Django Apps within a single website

User · Answer

Edit  2020-05-08  Is seems the website I quoted is no longer controlled by the person who wrote the advice  so I m removing the link to the site  Thanks for letting me know baxx     If someone s still struggling a bit after the great answers already provided  I found advice on a website that no longer is available   Essential quote from the site I mentioned       The same can be specified programmatically in this way       import sys      sys path append            Of course the code above must be written before the other import   statement    It s pretty obvious that it has to be this way  thinking on it after the fact  I was trying to use the sys path append       in my tests  but ran into the issue posted by OP  By adding the import and sys path defintion before my other imports  I was able to solve the problem

User · Answer

In my case  I had to change to this  Solution 1 more better which depend on current py file path  Easy to deploy  Use pathlib Path parents make code cleaner import sys import os import pathlib target path   pathlib Path os path abspath   file     parents 3  sys path append target path  from utils import MultiFileAllowed  Solution 2 import sys import os sys path append os getcwd    from utils import MultiFileAllowed

User · Answer

EDIT  There are better more coherent answers to this question in other questions     Sibling package imports Relative imports for the billionth time     Why doesn t it work  It s because python doesn t record where a package was loaded from  So when you do python -m test A test  it basically just discards the knowledge that test A test is actually stored in package  i e  package is not considered a package   Attempting from   A import foo is trying to access information it doesn t have any more  i e  sibling directories of a loaded location   It s conceptually similar to allowing from   os import path in a file in math  This would be bad because you want the packages to be distinct  If they need to use something from another package  then they should refer to them globally with from os import path and let python work out where that is with  PATH and  PYTHONPATH   When you use python -m package test A test  then using from   A import foo resolves just fine because it kept track of what s in package and you re just accessing a child directory of a loaded location   Why doesn t python consider the current working directory to be a package  NO CLUE  but gosh it would be useful

User · Answer

if you have an   init   py in an upper folder  you can initialize the import as import file path as alias in that init file  Then you can use it on lower scripts as   import alias

User · Answer

None of these solutions worked for me in 3 6  with a folder structure like   package1      subpackage1          module1 py package2      subpackage2          module2 py   My goal was to import from module1 into module2  What finally worked for me was  oddly enough   import sys sys path append        Note the single dot as opposed to the two-dot solutions mentioned so far     Edit  The following helped clarify this for me   import os print  os getcwd      In my case  the working directory was  unexpectedly  the root of the project

User · Answer

As the most popular answer suggests  basically its because your PYTHONPATH or sys path includes   but not your path to your package  And the relative import is relative to your current working directory  not the file where the import happens  oddly   You could fix this by first changing your relative import to absolute and then either starting it with   PYTHONPATH  path to package python -m test A test   OR forcing the python path when called this way  because   With python -m test A test you re executing test A test py with   name         main    and   file        absolute path to test A test py   That means that in test py you could use your absolute import semi-protected in the main case condition and also do some one-time Python path manipulation   from os import path     def main        if   name         main         import sys     sys path append path join path dirname   file                from A import foo      exit main

User · Answer

Not sure in python 2 x but in python 3 6  assuming you are trying to run the whole suite  you just have to use -t     -t  --top-level-directory directory   Top level directory of project  defaults to start directory    So  on a structure like  project root        ----- my module                                     my class py         tests            test my func py    One could for example use   python3 unittest discover -s  full path project root tests -t  full path project root   And still import the my module my class without major dramas

User · Answer

Assumption  If you are in the package directory  A and test A are separate packages    Conclusion    A imports are only allowed within a package    Further notes  Making the relative imports only available within packages is useful if you want to force that packages can be placed on any path located on sys path   EDIT      Am I the only one who thinks that this is insane   Why in the world is the current working directory not considered to be a package      Multihunter   The current working directory is usually located in sys path  So  all files there are importable  This is behavior since Python 2 when packages did not yet exist  Making the running directory a package would allow imports of modules as  import  A  and as  import A  which then would be two different modules  Maybe this is an inconsistency to consider

User · Answer

from package A import foo  I think it s clearer than  import sys sys path append

[python] beyond top level package error in relative import

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