svn commit: r366962 - in head: include usr.bin/calendar

[Warner Losh]

On Mon, Oct 26, 2020 at 12:01 AM Alex Kozlov <ak at freebsd.org> wrote:

> On Sun, Oct 25, 2020 at 11:37:34AM +0100, Stefan Esser wrote:
> > Am 25.10.20 um 06:56 schrieb Alex Kozlov:
> > > On Sat, Oct 24, 2020 at 04:37:45PM +0200, Stefan Esser wrote:
> > > > Am 24.10.20 um 09:48 schrieb Alex Kozlov:
> > [...]
> > > > > You are hardcoding assumption that LOCALBASE = /usr/local. Please
> make it
> > > > > overridable with LOCALBASE environment variable.
> > > > This was a trivial change to get us going with calendars provided by
> > > > a port (which has not been committed, yet - therefore there are no
> > > > port-provided calendars, neither under /usr/local nor under any other
> > > > PREFIX, as of now).
> > >
> > > > I understand what you are asking for, but in such a case I'd rather
> > > > think you want to rebuild FreeBSD with _PATH_LOCALBASE modified in
> > > > paths.h.
> > > The PREFIX != LOCALBASE and both != /usr/local configurations
> > > are supported in the ports tree and the base for a long time, please
> see
> > >
> https://www.freebsd.org/doc/en_US.ISO8859-1/books/porters-handbook/porting-prefix.html
> >
> > Yes, and I do not need to look that up in the handbook, having been
> > a ports committer for 2 decades by now.
> >
> > > If after this commit you need to rebuild base to use non-default
> LOCALBASE/PREFIX
> > > it is pretty big regression and POLA.
> >
> > How is that any different than before?
> >
> > What I did is make the PATH easier to change when you rebuild base.
> >
> > There are numerous programs in base that contain the literal string
> > /usr/local - and what I did was implement a mechanism that allows
> > to replace this literal reference with a simple change in paths.h.
> >
> > If you do not modify paths.h for a different LOCALBASE, then you'll
> > get a wrong _PATH_DEFPATH compiled into your binaries, for example.
> >
> > > > And I have made this a single instance that needs to be changed.
> > > > Before my change there were 2 instances of /usr/local hard-coded
> > > > in _PATH_DEFPATH - now you have to only change the definition of
> > > > _PATH_LOCALBASE to adjust all 3 locations that use it.
> > > I think you made situation worse, there were two stray hardcoded
> > > string and now there is official LOCALBASE define which likely will be
> > > used by other people in the future.
> >
> > I'd hope so to get rid of many of the 1713 literal uses of /usr/local
> > in our source tree.
> >
> > > > If you can show me precedence of a LOCALBASE environment variable
> > > > being used in the way you suggest, I'd be willing to make calendar
> > > > use it.
> > > Just an analogy from LOCALBASE make variable, perhaps CALENDAR_HOME
> > > is a better name.
> >
> > Yes, I already suggested CALENDAR_HOME, but as an environment variable
> > to check, if you want to be able to path an additional directory (or
> > search path) to the calendar program at run-time. But why introduce
> > a CALENDAR_HOME macro in the sources, if the port supplied calendar
> > files are known to be found at LOCALBASE/share/calendar (for some value
> > of LOCALBASE).
> >
> > I want to make more programs that currently hard-code /usr/local use
> > _PATH_LOCALBASE instead. This C macro can then be default to /usr/local
> > but can be overridden by passing LOCALBASE to the compiler (from the
> > build infrastructure) when paths.h is included.
> >
> > Instead of referring to _PATH_LOCALBASE these files could directly use
> > LOCALBASE, but since other paths are defined as _PATH_xxx in paths.h I
> > think it is best to follow this precedent.
> >
> > > > But then I think a CALENDAR_HOME variable would be even more useful,
> > > > since it would allow to search an additional user selected directory
> > > > (and not just share/calendar within what you provide as LOCALBASE).
> >
> > My change did not add any dependency on LOCALBASE to any previously
> > existing functionality. It added support for calendar files provided
> > by a port (a feature that did not exist before) at a location that is
> > correct for the big majority of users (who do not modify LOCALBASE).
> >
> > As I said: I'm going to make it easier to build the base system with
> > a different LOCALBASE, but not by run-time checking an environment
> > variable that specifies LOCALBASE in each affected program.
> It seems that you intend to follow through no matter what. So, just for
> the record, I think that hardcoding LOCALBASE and requiring base rebuild
> to change it is a very wrong approach.
>

So, first off, it's already hard coded. Stefan's changes change the hard
coding from 'impossible to change' to 'changeable with a recompile' which
is an improvement. It might even wind up as a build variable (or not, doing
that has some really ugly, nasty dependencies).

But even in ports-land, it's a compile time constant. Quite a large number
of ports will allow you to change it at compile / build time, but not
after. You have to rebuild if you want to change PREFIX...

So I'm a bit puzzled what makes this the wrong approach?

Warner