NFD

This should not be rejected, we need to know our limits. But in any case, apparently this is not an issue in waf, but in the way we're using waf. According to waf developers, all external tools (the ones that are currently in .waf-tools) needs to be bundled in inside waf script. This way, waf will take care of proper conversion to work with different versions of python.

Just discovered that we actually don't support python3 too. It is possible to fix, but would take some time and tricks.

Python 2.x is available on most platforms and is supported.

To avoid problems on systems that default to Python 3: change SHEBANG line to #!/usr/bin/python2

I wouldn't fix python, especially given the fix to support either 2.6+ or 3.0 is kind of trivial (I already submitted patches on gerrit)

Python2 and Python3 are fundamentally different languages - they are different syntax and thus different semantics.

Python2 is available as a package on all supported platforms.

Being compatible with Python3 appears easy, but it's an unnecessary burden on future development of wscript.

Therefore, I'm against making this change.

they are not that fundamentally different, they both functional and similar syntax.

waf itself is designed to be portable on "any" (any recent) version of python. i'm against on making any changes to build system (e.g., in waf that we bundle).

wscript technically supposed to be a simple script calling waf's functions, so the primary burden should be on waf guys, not on wscript.

NFD and ndn-cxx currently fail if the system python is version 3 or later (i.e. /usr/bin/python is python3)

$ python --version
Python 3.3.5

$ ./waf configure --help
Traceback (most recent call last):
  File "/home/davide/repos/NFD/.waf3-1.8.0-094bcb3e7079041614f60222067e94d3/waflib/Scripting.py", line 98, in waf_entry_point
    run_commands()
  File "/home/davide/repos/NFD/.waf3-1.8.0-094bcb3e7079041614f60222067e94d3/waflib/Scripting.py", line 155, in run_commands
    parse_options()
  File "/home/davide/repos/NFD/.waf3-1.8.0-094bcb3e7079041614f60222067e94d3/waflib/Scripting.py", line 128, in parse_options
    Context.create_context('options').execute()
  File "/home/davide/repos/NFD/.waf3-1.8.0-094bcb3e7079041614f60222067e94d3/waflib/Options.py", line 136, in execute
    super(OptionsContext,self).execute()
  File "/home/davide/repos/NFD/.waf3-1.8.0-094bcb3e7079041614f60222067e94d3/waflib/Context.py", line 92, in execute
    self.recurse([os.path.dirname(g_module.root_path)])
  File "/home/davide/repos/NFD/.waf3-1.8.0-094bcb3e7079041614f60222067e94d3/waflib/Context.py", line 133, in recurse
    user_function(self)
  File "/home/davide/repos/NFD/wscript", line 38, in options
    tooldir=['.waf-tools'])
  File "/home/davide/repos/NFD/.waf3-1.8.0-094bcb3e7079041614f60222067e94d3/waflib/Context.py", line 86, in load
    module=load_tool(t,path)
  File "/home/davide/repos/NFD/.waf3-1.8.0-094bcb3e7079041614f60222067e94d3/waflib/Context.py", line 342, in load_tool
    __import__(tool)
  File ".waf-tools/pch.py", line 86
    if getattr(self, 'headers', None) is None:
                                             ^
TabError: inconsistent use of tabs and spaces in indentation

Note that most other open source project usually support python2 >= 2.6 and python3 >= 3.2, so I think we can ignore < 2.6 and 3.0 and 3.1

In any case, if you don't want to support python3, at least change the shebang to reflect this.

If a supported platform can be configured to have /usr/bin/python as Python 3, and NFD build fails under such configuration, this shall be reported as a critical bug.

Is this simply a documentation bug or do we want to change something in waf/wscript?