Re: [PATCH] fetch/git: add support for disabling shared clones on unpack

[Henning Schild <henning.schild@siemens.com>]

Bump! Could i please get a review on this patch?

regards,
Henning

Am Wed, 20 Dec 2017 17:45:38 +0100
schrieb Henning Schild <henning.schild@siemens.com>:

> We actually ran into that issue on a build system called Isar.
> 
> https://github.com/ilbers/isar
> 
> This build system executes some tasks in a chroot. In this chroot a
> "shared" clone will not work because it expects its "alternate" to be
> at the very same location it was outside the chroot. We considered
> several hacks in Isar
> - patching the alternates before and after chroot
> - mounting the "alternate" to the exact location in chroot
> None of this is really nice, so we decided to try and do something
> about it upstream.
> 
> regards,
> Henning
> 
> Am Wed, 20 Dec 2017 17:42:09 +0100
> schrieb Henning Schild <henning.schild@siemens.com>:
> 
> > By default the unpacker will create a "shared" clone when cloning
> > from the DL_DIR to the WORKDIR. This patch introduces an option to
> > control that behaviour. Probably something that hardly anyone would
> > want to do.
> > 
> > Imagine some recipe steps are executed in a namespace that is
> > different from the one your downloader and unpacker ran in. (chroot)
> > Because a "shared" clone has an absolute reference to its
> > "alternate" you now have to make that "alternate" visible in that
> > new namespace (chroot) at the exact place.
> > 
> > With this patch you can unpack "noshared" and get a stand-alone
> > copy. This copy will also work if the "alternate" is not visible or
> > existant.
> > 
> > Signed-off-by: Henning Schild <henning.schild@siemens.com>
> > ---
> >  lib/bb/fetch2/git.py | 13 ++++++++++++-
> >  1 file changed, 12 insertions(+), 1 deletion(-)
> > 
> > diff --git a/lib/bb/fetch2/git.py b/lib/bb/fetch2/git.py
> > index 5ef8cd69..7b7f02b2 100644
> > --- a/lib/bb/fetch2/git.py
> > +++ b/lib/bb/fetch2/git.py
> > @@ -53,6 +53,13 @@ Supported SRC_URI options are:
> >     For local git:// urls to use the current branch HEAD as the
> > revision for use with AUTOREV. Implies nobranch.
> >  
> > +- noshared
> > +   When unpacking do not clone with the parameter "--shared". This
> > option will
> > +   allow the unpacked copy to work stand-alone i.e. if your recipe
> > runs in a
> > +   chroot where the "alternate" can not be found. Setting this will
> > increase
> > +   the unpack-time and the disk-usage.
> > +   The default is "0", set noshared=1 if needed.
> > +
> >  """
> >  
> >  #Copyright (C) 2005 Richard Purdie
> > @@ -159,6 +166,8 @@ class Git(FetchMethod):
> >  
> >          ud.nobranch = ud.parm.get("nobranch","0") == "1"
> >  
> > +        ud.noshared = ud.parm.get("noshared","0") == "1"
> > +
> >          # usehead implies nobranch
> >          ud.usehead = ud.parm.get("usehead","0") == "1"
> >          if ud.usehead:
> > @@ -176,7 +185,9 @@ class Git(FetchMethod):
> >          if len(branches) != len(ud.names):
> >              raise bb.fetch2.ParameterError("The number of name and
> > branch parameters is not balanced", ud.url) 
> > -        ud.cloneflags = "-s -n"
> > +        ud.cloneflags = "-n"
> > +        if not ud.noshared:
> > +            ud.cloneflags += " -s"
> >          if ud.bareclone:
> >              ud.cloneflags += " --mirror"
> >    
>