Re: [PATCH 3/5] gnu: Enable tests in Python 3.

[Cyril Roelandt <tipecaml@gmail.com>]

On 03/21/2014 02:15 PM, Ludovic Courtès wrote:
> Cyril Roelandt <tipecaml@gmail.com> skribis:
>
>> On 03/07/2014 10:40 AM, Ludovic Courtès wrote:
>>> Cyril Roelandt <tipecaml@gmail.com> skribis:
>
> [...]
>
>>>> +--- Lib/test/test_posixpath.py	2014-03-01 05:46:56.984311000 +0100
>>>> ++++ Lib/test/test_posixpath.py	2014-03-01 06:20:50.704311000 +0100
>>>> +@@ -319,7 +319,11 @@
>>>> +                 del env['HOME']
>>>> +                 home = pwd.getpwuid(os.getuid()).pw_dir
>>>> +                 # $HOME can end with a trailing /, so strip it (see #17809)
>>>> +-                self.assertEqual(posixpath.expanduser("~"), home.rstrip("/"))
>>>> ++		# The Guix builders have '/' as a home directory, so
>>>> ++		# home.rstrip("/") will be an empty string and the test will
>>>> ++		# fail. Let's just disable it since it does not really make
>>>> ++		# sense with such a bizarre setup.
>>>> ++                # self.assertEqual(posixpath.expanduser("~"), home.rstrip("/"))
>>>
>>> I see that the recipe’s ‘pre-check’ phase does:
>>>
>>>     (setenv "HOME" (getcwd))
>>>
>>> so $HOME should actually be /tmp/nix-build-xxx, not just /, no?
>>>
>>
>> Yes, but I think it uses getpwent() or something that does not use
>> $HOME to retrieve the home directory in this case.
>
> Here’s what I see, with nscd turned off (this uses getpwnam(2)):
>
> --8<---------------cut here---------------start------------->8---
> $ strace guile -c '(getpw "ludo")'
> [...]
> open("/etc/passwd", O_RDONLY|O_CLOEXEC) = 5
> fstat(5, {st_mode=S_IFREG|0644, st_size=2072, ...}) = 0
> mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f264dea5000
> read(5, "root:x:0:0:System administrator:"..., 4096) = 2072
> --8<---------------cut here---------------end--------------->8---
>
> Normally the chroot environment has all that too.  And indeed, the
> equivalent of the above Python snippet seems to work:
>
> --8<---------------cut here---------------start------------->8---
> scheme@(guile-user)> ,use(guix)
> scheme@(guile-user)> ,use(guix monads)
> scheme@(guile-user)> (define s (open-connection))
> scheme@(guile-user)> (derivation-expression "getpw" '(pk (getpw (getuid))))
> $11 = #<procedure 3da30f0 at guix/monads.scm:297:6 (store)>
> scheme@(guile-user)> (run-with-store s $11)
> $12 = #<derivation /gnu/store/bhmd5bg9s64an3s8ssmwx6l90dkr56hx-getpw.drv => /gnu/store/z68rzri3myxx1dg931fb1ksxdg7c29zg-getpw 33dfa00>
> scheme@(guile-user)> (build-derivations s (list $12))
> building path(s) `/gnu/store/z68rzri3myxx1dg931fb1ksxdg7c29zg-getpw'
>
> ;;; (#("nixbld" "x" 30001 30000 "Nix build user" "/" "/noshell"))

Am I misteading this, or is the home directory '/' for the nixbld user ? 
That's exactly what happens in Python (that uses getwpent). Hence the 
bug. I think skipping this assertion is the right thing to do here.

Cyril.