[Buildroot] [PATCH 6/7] Makefile: add check that $(HOST_DIR)/usr is not a directory

[Yann E. MORIN <yann.morin.1998@free.fr>]

Thomas, All,

On 2017-07-10 18:02 +0200, Thomas Petazzoni spake thusly:
> On Mon, 10 Jul 2017 01:21:22 +0200, Arnout Vandecappelle
> (Essensium/Mind) wrote:
> > We create a compatibility symlink for $(HOST_DIR)/usr. However, if
> > that exists already as a directory, the link can't be created. Make
> > will not even try since it exists already and has no dependencies. If
> > it exists as a directory, any post-build script that is still using
> > $(HOST_DIR)/usr will fail to find what it needs. Therefore, add a
> > check that it is not a directory.
> > 
> > This check has to be made as part of some PHONY target. We can reuse
> > the dirs target, on which all packages depend.
> > 
> > Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
> > Cc: Yann E. MORIN <yann.morin.1998@free.fr>
> > ---
> > Personally I don't think it's important enough to add such a check.
> > If someone ends up in this situation, they'll be motivated to fix
> > their post-build scripts :-)
> 
> I also don't like very much adding such checks. In which situation can
> our users fall into this problem?

I've explained it in details when you initially reported the issue of
regenerating the toolchains:

    http://lists.busybox.net/pipermail/buildroot/2017-July/197456.html

> They have an existing Buildroot tree, they do "git pull" and do a
> partial rebuild ?

No, that occurs when a user points HOST_DIR outside, like you do for the
toolchains, and that host-dir already exists, and it already contains a
usr/ directory.

My opinion is that we should not allow using HOST_DIR if it is not empty
at all.

Regards,
Yann E. MORIN.

> > diff --git a/Makefile b/Makefile
> > index 188ce9adc7..a94555d130 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -542,6 +542,11 @@ endif
> >  .PHONY: dirs
> >  dirs: $(BUILD_DIR) $(STAGING_DIR) $(TARGET_DIR) \
> >  	$(HOST_DIR) $(HOST_DIR)/usr $(BINARIES_DIR)
> > +	@if [ -d "$(HOST_DIR)/usr" -a ! -L "$(HOST_DIR)/usr" ]; then \
> > +		printf '%s is not allowed to be a directory\n' "$(HOST_DIR)/usr" 1>&2; \
> > +		printf 'Please remove this directory and rebuild\n' 1>&2; \
> 
> What about saying "Please run make clean all" ?
> 
> Thomas
> -- 
> Thomas Petazzoni, CTO, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 223 225 172 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'