Re: proposal to make bootstrap on Linux prefer pkgsrc by default.

[Jason Bacon <outpaddling%yahoo.com@localhost>]

On 2020-08-10 11:44, Greg Troxel wrote:
> Jason Bacon <outpaddling%yahoo.com@localhost> writes:
>
> > On 2020-08-09 13:08, Greg Troxel wrote:
> > > Jason Bacon <outpaddling%yahoo.com@localhost> writes:
> > >
> > > Do you intend to change it, or do you think there is some reason not to,
> > > or that others object?  As I said above, my only goal here is that we
> > > adjust defaults to the consensus of best practice.
> > My aim here was to recap and clarify my experience with this issue so
> > we have a solid foundation on record for the argument.  So yes, I
> > think PREFER_PKGSRC should be the default.
> Sounds good to me, and you have definitely convinced me.
>
> I have changed the subject to reflect the proposed change of default.
>
> > Should it be changed just for Linux, or for other platforms as well?
> So far, we have had discussion that supports changing it on Linux.
> Specific othesr, not so much, and "all others", not at all.  So I'd
> prefer to just change it on Linux where we have a good basis to believe
> that's in the interest of someone who doesn't understand this issue and
> runs bootstrap.
>
> > Are we simply talking about something like the following in the
> > bootstrap script or is it more complicated?
> >
> > --- Pkgsrc/pkgsrc/bootstrap/bootstrap.orig    2020-08-10
> > 09:31:25.512000000 +0000
> > +++ Pkgsrc/pkgsrc/bootstrap/bootstrap    2020-08-10 09:36:00.236000000 +0000
> > @@ -1103,6 +1103,14 @@
> >   echo "PKGMANDIR=        $pkgmandir" >> ${TARGET_MKCONF}
> >   echo "" >> ${TARGET_MKCONF}
> >
> > +case $opsys in
> > +Linux)
> > +    if [ -z "$prefer_pkgsrc" ]; then
> > +        prefer_pkgsrc="yes"
> > +    fi
> > +    ;;
> > +esac
> > +
> >   if [ -n "$prefer_pkgsrc" ]; then
> >       echo "PREFER_PKGSRC=        $prefer_pkgsrc" >> ${TARGET_MKCONF}
> >       echo "" >> ${TARGET_MKCONF}
> I think there probably needs to be a doc change, and there needs to be a
> prefer-native that causes this not to happen, etc.  But basically, that
> seems like it.
And a draft patch for the guide...

Index: files/buildlink.xml
===================================================================
RCS file: /cvsroot/pkgsrc/doc/guide/files/buildlink.xml,v
retrieving revision 1.43
diff -u -r1.43 buildlink.xml
--- files/buildlink.xml 20 Jun 2020 09:47:05 -0000      1.43
+++ files/buildlink.xml 10 Aug 2020 20:28:19 -0000
@@ -602,16 +602,40 @@
       file to be listed in <varname>PREFER_NATIVE</varname>,
       otherwise it is simply ignored in that list.</para>

-      <para>Setting <varname>PREFER_NATIVE</varname> should be performed
-      straight after bootstrap and <varname>PREFER_PKGSRC</varname> during
-      bootstrap.
+      <para><varname>PREFER_PKGSRC</varname> should be set during bootstrap
+      to ensure that the bootstrap process does not use native tools as
+      dependencies for core packages.
+      Setting <varname>PREFER_NATIVE</varname> should be performed
+      immediately after bootstrap at the latest, but can also be set
+      during bootstrap.
       Switching between settings globally at a later date can introduce
       complications with dependency resolution. This is caused by packages
-      built with the opposite preference being installed alongside each 
other.</para>
-
+      built with the opposite preference being installed alongside each
+      other.  Hence, it is advisable to rebuild all installed packages
+      following any changes to these variables.</para>
+
 <screen>
 &rprompt; <userinput>./bootstrap --prefer-pkgsrc yes</userinput>
+&rprompt; <userinput>./bootstrap --prefer-native openssl</userinput>
 </screen>
+
+      <para>When using pkgsrc on Linux systems, there is high risk of
+      "leakage", where programs installed by pkgsrc may inadvertently use a
+      command or library not installed by pkgsrc, e.g. those installed by
+      yum or apt.  Such foreign dependencies may be installed, removed, or
+      upgraded to a version incompatible with the pkgsrc package at any
+      time, causing pkgsrc packages to subsequently malfunction. Pkgsrc
+      cannot prevent this, as it has no control over other package 
managers.
+      Another potential problem is that under Redhat Enterprise and related
+      Linux systems, yum packages are only patched and never upgraded, so
+      eventually they may become too outdated for use by pkgsrc. Even
+      intentionally using foreign dependencies, not considered leakage, can
+      lead to these problems, so it is generally discouraged.  In order to
+      minimize such problems, PREFER_PKGSRC defaults to "yes" on Linux 
systems.
+      This ensures that pkgsrc is aware of any changes to dependency 
packages
+      and can rebuild or upgrade the entire dependency tree as needed.  
This
+      default can be overridden by setting --prefer-pkgsrc to "no" or a 
list of
+      packages, or by setting --prefer-native to "yes".</para>
     </sect2>
   </sect1>
 </chapter>