Changes between Version 10 and Version 34 of Ticket #22756


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Timestamp:
04/07/17 22:49:08 (3 years ago)
Author:
jhpalmieri
Comment:

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  • Ticket #22756

    • Property Commit changed from c050438fa802d56738cc7084254579c5610b7358 to 678fb206f5fb7731651c80263c61ac4872915396
  • Ticket #22756 – Description

    v10 v34  
    1 On OS X, Python3 sometimes fails to build correctly. I think it depends on whether Python2 is built first or not. Even if it seems to build correctly, then the `_scproxy` module is broken.
     1On OS X, Python3 sometimes fails to build correctly. To fix this:
    22
    3 Examples (all start with `make distclean`):
     3- make `xz` a dependency: not necessary for Python 3 to build, but this way it builds the `_lzma` module.
    44
    5 - `./sage -i python3`. Then `python3` works, but the `_scproxy` (on OS X 10.12) and `_lzma` modules fail to build. We've seen the `_scproxy` error before: the solution is to compile with clang, at least on recent versions of OS X. The error for `_lzma` is
    6 {{{
    7 /Users/palmieri/Desktop/Sage_stuff/sage_builds/TESTING/sage-8.0.beta0/local/var/tmp/sage/build/python3-3.5.1/src/Modules/_lzmamodule.c:19:18: fatal error: lzma.h: No such file or directory
    8 }}}
    9  We can fix this by making `xz` a dependency. Is it important? `xz` doesn't take long to build and doesn't have any dependencies of its own, so why not?
     5- use `clang` to compile Python 3, as we do for Python 2. Without this, the `_scproxy` module fails to build.
    106
    11 - `./sage -i python2; ./sage -i python3`: then Python3 fails with the error
    12 {{{
    13 $ sage --sh
    14 $ python3
    15 Fatal Python error: Py_Initialize: unable to load the file system codec
    16   File "/Users/jpalmier/Desktop/Sage_stuff/git/sage/local/lib/python/encodings/__init__.py", line 123
    17     raise CodecRegistryError,\
    18                             ^
    19 SyntaxError: invalid syntax
     7- do not create a symlink `SAGE_LOCAL/lib/python` -- see #22764. If this symlink is in place and if Python 2 is built before Python 3, then Python 3 picks up that link in its load path, and so it tries to read a lot of Python 2 packages, which is bad.
    208
    21 Current thread 0x00007fff76225000 (most recent call first):
    22 Abort trap: 6
    23 }}}
     9- see also #22781 which tracks a few other issues related to Python 3, OS X, and Sage packages.
    2410
    25 - if we build Python3 with `clang`, the way we do with Python2, then as long as we haven't built Python2 first, it works and `_scproxy` builds properly. `_lzma` doesn't, but we can fix that.
    26 
    27 - if we build Python3 with `clang` but we build Python2 first, then we get the same error as above.
    28 
    29 So I propose that we build Python3 with `clang` as we already do with Python2, and we make `xz` a dependency. To fix the interference between the two Python builds, we should remove the symbolic link `SAGE_LOCAL/lib/python`. See #22764.