python3: use stdlib UUID backend

Python3 at runtime identifies the uuid backend to use to implement
functions like uuid_generate_time. This search includes libc first
and then other options like util-linux's libuuid.  There is also an
option to use an extension module, however it looks like that requires
the libuuid and headers to be present (./Modules/_uuidmodule.c).  The
extension isn't required to make this work.

 - This was runtime tested by updating the python3-3.7.0/Lib/uuid.py
   to include debug information in the def _load_system_functions():
   to print "libname".  Then at runtime it was observed that libc
   was the selected backend.

 - At build time, the log was checked to confirmed the configure step
   didn't detect any uuid support in both the case of util-linux
   present and not. However, this did not prevent the uuid runtime
   from working. Thus the reason the patch 0031-* which adds the opt
   to disable uuid has no affect.

This patch removes the enable/disable option as it is no longer
required since python's use of libc should be possible in every system.
Note: Currently the BR2_PACKAGE_PYTHON3_UUID disable doesn't work to
prevent the "import uuid ; print(uuid.uuid1())" example from working
at runtime.

This patch drops the dependency on util-linux as the library isn't
required for a working python uuid implementation.  The enabling of
libuuid.so in a Buildroot configuration doesn't currently have any
affect on the feature, as python still uses the libc backend.

Ref:
http://lists.busybox.net/pipermail/buildroot/2018-October/233113.html
http://lists.busybox.net/pipermail/buildroot/2018-September/231060.html
http://lists.busybox.net/pipermail/buildroot/2018-October/233079.html

CC: Adam Duskett <aduskett@greenlots.com>
CC: Adam Duskett <aduskett@gmail.com>
Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
---
 ...0031-Add-an-option-to-disable-uuid-module.patch | 33 ----------------------
 package/python3/Config.in                          | 10 -------
 package/python3/python3.mk                         |  6 ----
 3 files changed, 49 deletions(-)
 delete mode 100644 package/python3/0031-Add-an-option-to-disable-uuid-module.patch

> From: "Matthew Weber" <matthew.weber@rockwellcollins.com>
> To: "buildroot" <buildroot@buildroot.org>
> Cc: "Adam Duskett" <aduskett@greenlots.com>, "ratbert90" <aduskett@gmail.com>
> Sent: Friday, October 12, 2018 11:14:48 AM
> Subject: [Buildroot] [PATCH] python3: use stdlib UUID backend

Tested-by: Carlos Santos <casantos@datacom.com.br>

Hello,

On Fri, 12 Oct 2018 09:14:48 -0500, Matt Weber wrote:

> diff --git a/package/python3/0031-Add-an-option-to-disable-uuid-module.patch b/package/python3/0031-Add-an-option-to-disable-uuid-module.patch
> deleted file mode 100644
> index c429c59..0000000
> --- a/package/python3/0031-Add-an-option-to-disable-uuid-module.patch
> +++ /dev/null
> @@ -1,33 +0,0 @@
> -From 1fe33c7bee9e6410f56c956ea19efd2f617176ae Mon Sep 17 00:00:00 2001
> -From: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
> -Date: Sat, 18 Aug 2018 10:54:56 +0200
> -Subject: [PATCH] Add an option to disable uuid module
> -
> -Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
> ----
> - configure.ac | 9 +++++++++
> - 1 file changed, 9 insertions(+)
> -
> -diff --git a/configure.ac b/configure.ac
> -index b022460e73..505b7c9be0 100644
> ---- a/configure.ac
> -+++ b/configure.ac
> -@@ -3258,6 +3258,15 @@ if test "$CURSES" = "no"; then
> -    DISABLED_EXTENSIONS="${DISABLED_EXTENSIONS} _curses _curses_panel"
> - fi
> - 
> -+AC_SUBST(UUID)
> -+AC_ARG_ENABLE(uuid,
> -+	AS_HELP_STRING([--disable-uuid], [disable uuid]),
> -+	[ UUID="${enableval}" ], [ UUID=yes ])
> -+
> -+if test "$UUID" = "no"; then
> -+   DISABLED_EXTENSIONS="${DISABLED_EXTENSIONS} _uuid"
> -+fi
> -+
> - AC_SUBST(PYDOC)
> - 
> - AC_ARG_ENABLE(pydoc,

I am not sure it is a good idea to drop this patch. Indeed, without
this patch, Python will auto-detect the presence of util-linux (if it
gets built before), and use it. This means that we don't have the same
Python configuration depending on whether util-linux is built before
Python or not.

Keeping the patch would allow to pass an unconditional --disable-uuid.

Best regards,

Thomas

Thomas,

On Thu, Oct 18, 2018 at 7:56 AM Thomas Petazzoni
<thomas.petazzoni@bootlin.com> wrote:
>
> Hello,
>
> On Fri, 12 Oct 2018 09:14:48 -0500, Matt Weber wrote:
>
> > diff --git a/package/python3/0031-Add-an-option-to-disable-uuid-module.patch b/package/python3/0031-Add-an-option-to-disable-uuid-module.patch
> > deleted file mode 100644
> > index c429c59..0000000
> > --- a/package/python3/0031-Add-an-option-to-disable-uuid-module.patch
> > +++ /dev/null
> > @@ -1,33 +0,0 @@
> > -From 1fe33c7bee9e6410f56c956ea19efd2f617176ae Mon Sep 17 00:00:00 2001
> > -From: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
> > -Date: Sat, 18 Aug 2018 10:54:56 +0200
> > -Subject: [PATCH] Add an option to disable uuid module
> > -
> > -Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
> > ----
> > - configure.ac | 9 +++++++++
> > - 1 file changed, 9 insertions(+)
> > -
> > -diff --git a/configure.ac b/configure.ac
> > -index b022460e73..505b7c9be0 100644
> > ---- a/configure.ac
> > -+++ b/configure.ac
> > -@@ -3258,6 +3258,15 @@ if test "$CURSES" = "no"; then
> > -    DISABLED_EXTENSIONS="${DISABLED_EXTENSIONS} _curses _curses_panel"
> > - fi
> > -
> > -+AC_SUBST(UUID)
> > -+AC_ARG_ENABLE(uuid,
> > -+    AS_HELP_STRING([--disable-uuid], [disable uuid]),
> > -+    [ UUID="${enableval}" ], [ UUID=yes ])
> > -+
> > -+if test "$UUID" = "no"; then
> > -+   DISABLED_EXTENSIONS="${DISABLED_EXTENSIONS} _uuid"
> > -+fi
> > -+
> > - AC_SUBST(PYDOC)
> > -
> > - AC_ARG_ENABLE(pydoc,
>
> I am not sure it is a good idea to drop this patch. Indeed, without
> this patch, Python will auto-detect the presence of util-linux (if it
> gets built before), and use it. This means that we don't have the same
> Python configuration depending on whether util-linux is built before
> Python or not.
>
> Keeping the patch would allow to pass an unconditional --disable-uuid.
>

Ah ic, I didn't think about the order of the auto-detect.  I agree the
patch should stay and a unconditional --disable-uuid should be passed
but a note added stating uuid support falls back to libc when
util-linux isn't present.

Matt