[PATCH] Makefile: Correctly propagate failure when removing target

["Pali Rohár" <pali@kernel.org>]

On Tuesday 27 October 2020 20:10:37 Simon Glass wrote:
> Hi Paul,
> 
> On Mon, 26 Oct 2020 at 07:11, Pali Roh?r <pali@kernel.org> wrote:
> >
> > On more places is used pattern 'command > $@ || rm -f $@'. But it does not
> > propagate failure from 'command' as 'rm -f' returns success.
> >
> > Fix it by calling 'false' to correctly propagate failure after 'rm -f'.
> >
> > Signed-off-by: Pali Roh?r <pali@kernel.org>
> > ---
> >  Makefile | 12 ++++++------
> >  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> Reviewed-by: Simon Glass <sjg@chromium.org>
> 
> But I'm not sure about the use of {}. I would normally use ()

( ... ) spawns new shell and run commands in that new shell
{ ... ; } groups command together and runs them in the current shell

So { ... ; } should be more efficient as it spawns less processes. But
result should be same, return value from 'false', which returns 1.

I'm using { ... ; } when it is not needed to spawns new processes and
running commands in current shell is fine. I think that writing ( ... )
should be equivalent to sh -c '...' (with correctly exported variables).

> 
> >
> > diff --git a/Makefile b/Makefile
> > index 5a0ef18668..94feb7d9a5 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -1005,7 +1005,7 @@ cmd_cat = cat $(filter-out $(PHONY), $^) > $@
> >  append = cat $(filter-out $< $(PHONY), $^) >> $@
> >
> >  quiet_cmd_pad_cat = CAT     $@
> > -cmd_pad_cat = $(cmd_objcopy) && $(append) || rm -f $@
> > +cmd_pad_cat = $(cmd_objcopy) && $(append) || { rm -f $@; false; }
> >
> >  quiet_cmd_lzma = LZMA    $@
> >  cmd_lzma = lzma -c -z -k -9 $< > $@
> > @@ -1312,7 +1312,7 @@ endif
> >  shell_cmd = { $(echo-cmd) $(cmd_$(1)); }
> >
> >  quiet_cmd_objcopy_uboot = OBJCOPY $@
> > -cmd_objcopy_uboot = $(cmd_objcopy) && $(call shell_cmd,static_rela,$<,$@,$(CONFIG_SYS_TEXT_BASE)) || rm -f $@
> > +cmd_objcopy_uboot = $(cmd_objcopy) && $(call shell_cmd,static_rela,$<,$@,$(CONFIG_SYS_TEXT_BASE)) || { rm -f $@; false; }
> >
> >  u-boot-nodtb.bin: u-boot FORCE
> >         $(call if_changed,objcopy_uboot)
> > @@ -1584,12 +1584,12 @@ u-boot.spr: spl/u-boot-spl.img u-boot.img FORCE
> >  ifneq ($(CONFIG_ARCH_SOCFPGA),)
> >  quiet_cmd_gensplx4 = GENSPLX4 $@
> >  cmd_gensplx4 = cat     spl/u-boot-spl.sfp spl/u-boot-spl.sfp   \
> > -                       spl/u-boot-spl.sfp spl/u-boot-spl.sfp > $@ || rm -f $@
> > +                       spl/u-boot-spl.sfp spl/u-boot-spl.sfp > $@ || { rm -f $@; false; }
> >  spl/u-boot-splx4.sfp: spl/u-boot-spl.sfp FORCE
> >         $(call if_changed,gensplx4)
> >
> >  quiet_cmd_socboot = SOCBOOT $@
> > -cmd_socboot = cat      spl/u-boot-splx4.sfp u-boot.img > $@ || rm -f $@
> > +cmd_socboot = cat      spl/u-boot-splx4.sfp u-boot.img > $@ || { rm -f $@; false; }
> >  u-boot-with-spl.sfp: spl/u-boot-splx4.sfp u-boot.img FORCE
> >         $(call if_changed,socboot)
> >
> > @@ -1599,12 +1599,12 @@ cmd_gensplpadx4 =  dd if=/dev/zero of=spl/u-boot-spl.pad bs=64 count=1024 ; \
> >                         spl/u-boot-spl.sfp spl/u-boot-spl.pad \
> >                         spl/u-boot-spl.sfp spl/u-boot-spl.pad \
> >                         spl/u-boot-spl.sfp spl/u-boot-spl.pad > $@ || \
> > -                       rm -f $@ spl/u-boot-spl.pad
> > +                       { rm -f $@ spl/u-boot-spl.pad; false; }
> >  u-boot-spl-padx4.sfp: spl/u-boot-spl.sfp FORCE
> >         $(call if_changed,gensplpadx4)
> >
> >  quiet_cmd_socnandboot = SOCNANDBOOT $@
> > -cmd_socnandboot = cat  u-boot-spl-padx4.sfp u-boot.img > $@ || rm -f $@
> > +cmd_socnandboot = cat  u-boot-spl-padx4.sfp u-boot.img > $@ || { rm -f $@; false; }
> >  u-boot-with-nand-spl.sfp: u-boot-spl-padx4.sfp u-boot.img FORCE
> >         $(call if_changed,socnandboot)
> >
> > --
> > 2.20.1
> >