Change shebangs to specify python2 instead of system default

[Mitame]

This replaces all shebangs in the python scripts to use python2 instead of system default. This is because not all of the python scripts support running in python3. The new shebangs use #!/usr/bin/env python2

[harlanhaskins]

OS X doesn't have a python2 binding by default.

It does have a python2.7

[Mitame]

Really? That sounds very odd indeed... does env not account for that?

[harlanhaskins]

harlan@nietzsche ~> /usr/bin/env python2
env: python2: No such file or directory
harlan@nietzsche ~> /usr/bin/env python2.6
Python 2.6.9 (unknown, Oct 23 2015, 18:17:02)
[GCC 4.2.1 Compatible Apple LLVM 7.0.0 (clang-700.0.59.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> exit()

[alexwlchan]

Have you changed all the scripts, or just the ones which fail under Python 3?

I’d be happy to work on getting them to run cleanly on either version. :-)

---

I’m also getting “No such file or directory” when I run env python2.

[brks]

@harlanhaskins It does for me.

[Mitame]

I changed the header for all those that just specified "python" and am building swift right now. ArchLinux defaults to python3 for python so it doesn't build correctly with the scripts unless you force python2. Basically, i replaced #!/usr/bin/python and #!/usr/bin/env python with #!/usr/bin/env python2.

[Mitame]

For reference, this is the error you get if you try to run utils/build-script with python3:

emati@mita:~/git/swift/swift$ python3 utils/build-script
Traceback (most recent call last):
  File "utils/build-script", line 24, in <module>
    from SwiftBuildSupport import *
  File "/home/emati/git/swift/swift/utils/SwiftBuildSupport.py", line 15, in <module>
    import ConfigParser
ImportError: No module named 'ConfigParser'```

[alexwlchan]

@Mitame Fix for that particular issue is in 5796230.

[nico]

This will break things on OS X. #90 is a better fix that will also make things to on arch. This should be closed.

[Mitame]

Yea, i was waiting for #90 to be accepted before closing this.

[cnd]

cuurently with master

λ ./utils/update-checkout --clone                                                                                                                                                                     ~/H/swift/ ∅
Traceback (most recent call last):
  File "./utils/update-checkout", line 20, in <module>
    from SwiftBuildSupport import (
  File "/root/H/swift/utils/SwiftBuildSupport.py", line 135
    except ConfigParser.InterpolationMissingOptionError, e:
                                                       ^
SyntaxError: invalid syntax
λ python --version                                                                                                                                                                                    ~/H/swift/ ∅
Python 3.4.3

and same with ConfigParser

[gribozavr]

@Heather Would you mind trying again? I just pushed 259fb78.

[cnd]

@gribozavr there are still being a lot of missing stuff from #90

[gribozavr]

@Heather I understand, but I can run python3 build-script successfully with that change. #90 includes many changes to scripts that are not on the critical path to building Swift.

[cnd]

@gribozavr I don't know how your python3 is working

λ cd swift                                                                                                                                                                                                    ~/ Π
λ ./utils/update-checkout --clone                                                                                                                                                                       ~/swift/ Π
Traceback (most recent call last):
  File "./utils/update-checkout", line 125, in <module>
    sys.exit(main())
  File "./utils/update-checkout", line 98, in main
    obtain_additional_swift_sources()
  File "./utils/update-checkout", line 69, in obtain_additional_swift_sources
    for dir_name, repo in additional_repos.iteritems():
AttributeError: 'dict' object has no attribute 'iteritems'
λ                                                                                                                                                                                                       ~/swift/ ∅

[cnd]

@gribozavr by the way there are other python files with similar issues... for now I just manually set them to python2. I can elaborate consistent patch for python3 compatibility but not sure if there is already work in progress by @alexwlchan or not

[gribozavr]

@Heather I didn't catch it because I had all repositories checked out and that code wasn't executed. Pushed a fix e0479df.

[cnd]

@gribozavr thanks but at least build scripts either should be updated...

[harlanhaskins]

So, macOS Sierra doesn't have an alias for python2 in the default PATH either, so I'm going to close this until we find a better solution. I think we need to figure out a better solution for the python2/3 discrepancy here. In the meantime, if you have python3 as your system python, I'd recommend making a virtual environment such that python2 resolves as python:

pip install virtualenv
virtualenv .swift-environment -p $(which python2)
source .swift-environment/bin/activate