| Message ID | 1517877294-4826-7-git-send-email-yamada.masahiro@socionext.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Feb 06, 2018 at 09:34:46AM +0900, Masahiro Yamada wrote: > The variable 'PYTHON' allows users to specify a proper executable > name in case the default 'python' does not work. However, this does > not address the case where both Python 2 and Python 3 scripts are > used in one system. > > PEP 394 (https://www.python.org/dev/peps/pep-0394/) provides a > convention for Python scripts portability. Here is a quotation: > > In order to tolerate differences across platforms, all new code > that needs to invoke the Python interpreter should not specify > 'python', but rather should specify either 'python2' or 'python3'. > This distinction should be made in shebangs, when invoking from a > shell script, when invoking via the system() call, or when invoking > in any other context. > > arch/ia64/scripts/unwcheck.py is apparently written in Python 2, so > it should be invoked by 'python2'. > > It is legitimate to use 'python' for scripts compatible with both > Python 2 and Python 3, but this is rare (at least I do not see the > case in kernel tree). You do not need to make efforts to write your > scripts in that way. Anyway, Python 2 will retire in 2020. > > This commit is needed for my new scripts written in Python 3. > > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > --- > > Makefile | 5 +++-- > arch/ia64/Makefile | 2 +- > 2 files changed, 4 insertions(+), 3 deletions(-) > > diff --git a/Makefile b/Makefile > index 11aff0f..c4e935c 100644 > --- a/Makefile > +++ b/Makefile > @@ -384,7 +384,8 @@ GENKSYMS = scripts/genksyms/genksyms > INSTALLKERNEL := installkernel > DEPMOD = /sbin/depmod > PERL = perl > -PYTHON = python > +PYTHON2 = python2 > +PYTHON3 = python3 Is this going to break any systems that were previous setting PYTHON? I like this change, and feel it is the correct thing to do, but having a "fallback" might be needed here. Could you do what the perf makefile does and do something like: override PYTHON := $(call get-executable-or-default,PYTHON,$(PYTHON2)) or is it really not an issue as only ia64 seems to care about this? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
2018-02-06 18:34 GMT+09:00 Greg Kroah-Hartman <gregkh@linuxfoundation.org>: > On Tue, Feb 06, 2018 at 09:34:46AM +0900, Masahiro Yamada wrote: >> The variable 'PYTHON' allows users to specify a proper executable >> name in case the default 'python' does not work. However, this does >> not address the case where both Python 2 and Python 3 scripts are >> used in one system. >> >> PEP 394 (https://www.python.org/dev/peps/pep-0394/) provides a >> convention for Python scripts portability. Here is a quotation: >> >> In order to tolerate differences across platforms, all new code >> that needs to invoke the Python interpreter should not specify >> 'python', but rather should specify either 'python2' or 'python3'. >> This distinction should be made in shebangs, when invoking from a >> shell script, when invoking via the system() call, or when invoking >> in any other context. >> >> arch/ia64/scripts/unwcheck.py is apparently written in Python 2, so >> it should be invoked by 'python2'. >> >> It is legitimate to use 'python' for scripts compatible with both >> Python 2 and Python 3, but this is rare (at least I do not see the >> case in kernel tree). You do not need to make efforts to write your >> scripts in that way. Anyway, Python 2 will retire in 2020. >> >> This commit is needed for my new scripts written in Python 3. >> >> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> >> --- >> >> Makefile | 5 +++-- >> arch/ia64/Makefile | 2 +- >> 2 files changed, 4 insertions(+), 3 deletions(-) >> >> diff --git a/Makefile b/Makefile >> index 11aff0f..c4e935c 100644 >> --- a/Makefile >> +++ b/Makefile >> @@ -384,7 +384,8 @@ GENKSYMS = scripts/genksyms/genksyms >> INSTALLKERNEL := installkernel >> DEPMOD = /sbin/depmod >> PERL = perl >> -PYTHON = python >> +PYTHON2 = python2 >> +PYTHON3 = python3 > > Is this going to break any systems that were previous setting PYTHON? > > I like this change, and feel it is the correct thing to do, but having a > "fallback" might be needed here. > > Could you do what the perf makefile does and do something like: > override PYTHON := $(call get-executable-or-default,PYTHON,$(PYTHON2)) > or is it really not an issue as only ia64 seems to care about this? > As far as I see, ia64 is the only instance that has used this ever. (the perf Makefile defines PYTHON by itself, so should not be a problem.) If people expect the backward-compatibility for this, I can do like follows: # backward compatibility for 'PYTHON' PYTHON2 := $(if $(PYTHON), $(PYTHON), python2) Another (unlikely) possible breakage is 'python2' may not be installed on users' system. I believe this is rare, but if needed, I could do like follows at the cost of ugliness. PYTHON2 := $(if $(PYTHON), $(PYTHON), \ $(shell python2 --version 2>/dev/null && echo python2 || echo python))
On Tue, Feb 06, 2018 at 07:44:22PM +0900, Masahiro Yamada wrote: > 2018-02-06 18:34 GMT+09:00 Greg Kroah-Hartman <gregkh@linuxfoundation.org>: > > On Tue, Feb 06, 2018 at 09:34:46AM +0900, Masahiro Yamada wrote: > >> The variable 'PYTHON' allows users to specify a proper executable > >> name in case the default 'python' does not work. However, this does > >> not address the case where both Python 2 and Python 3 scripts are > >> used in one system. > >> > >> PEP 394 (https://www.python.org/dev/peps/pep-0394/) provides a > >> convention for Python scripts portability. Here is a quotation: > >> > >> In order to tolerate differences across platforms, all new code > >> that needs to invoke the Python interpreter should not specify > >> 'python', but rather should specify either 'python2' or 'python3'. > >> This distinction should be made in shebangs, when invoking from a > >> shell script, when invoking via the system() call, or when invoking > >> in any other context. > >> > >> arch/ia64/scripts/unwcheck.py is apparently written in Python 2, so > >> it should be invoked by 'python2'. > >> > >> It is legitimate to use 'python' for scripts compatible with both > >> Python 2 and Python 3, but this is rare (at least I do not see the > >> case in kernel tree). You do not need to make efforts to write your > >> scripts in that way. Anyway, Python 2 will retire in 2020. > >> > >> This commit is needed for my new scripts written in Python 3. > >> > >> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > >> --- > >> > >> Makefile | 5 +++-- > >> arch/ia64/Makefile | 2 +- > >> 2 files changed, 4 insertions(+), 3 deletions(-) > >> > >> diff --git a/Makefile b/Makefile > >> index 11aff0f..c4e935c 100644 > >> --- a/Makefile > >> +++ b/Makefile > >> @@ -384,7 +384,8 @@ GENKSYMS = scripts/genksyms/genksyms > >> INSTALLKERNEL := installkernel > >> DEPMOD = /sbin/depmod > >> PERL = perl > >> -PYTHON = python > >> +PYTHON2 = python2 > >> +PYTHON3 = python3 > > > > Is this going to break any systems that were previous setting PYTHON? > > > > I like this change, and feel it is the correct thing to do, but having a > > "fallback" might be needed here. > > > > Could you do what the perf makefile does and do something like: > > override PYTHON := $(call get-executable-or-default,PYTHON,$(PYTHON2)) > > or is it really not an issue as only ia64 seems to care about this? > > > > As far as I see, ia64 is the only instance that has used this ever. > > (the perf Makefile defines PYTHON by itself, so should not be a problem.) > > > If people expect the backward-compatibility for this, I can do like follows: > > # backward compatibility for 'PYTHON' > PYTHON2 := $(if $(PYTHON), $(PYTHON), python2) That's true, and who knows if python3 is running on ia64 :) > Another (unlikely) possible breakage is > 'python2' may not be installed on users' system. > > I believe this is rare, but if needed, I could do like follows > at the cost of ugliness. > > > PYTHON2 := $(if $(PYTHON), $(PYTHON), \ > $(shell python2 --version 2>/dev/null && echo python2 || echo python)) Ick, I guess that might work. Try getting your patch set into the 0-day system to see how it handles things. I know it builds for ia64. But this is a real tiny question overall, and should not derail this patchset at all :) thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> That's true, and who knows if python3 is running on ia64 :)
$ python3
-bash: python3: command not found
So I don't have it installed on my ia64 test/build machine.
-Tony
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diff --git a/Makefile b/Makefile index 11aff0f..c4e935c 100644 --- a/Makefile +++ b/Makefile @@ -384,7 +384,8 @@ GENKSYMS = scripts/genksyms/genksyms INSTALLKERNEL := installkernel DEPMOD = /sbin/depmod PERL = perl -PYTHON = python +PYTHON2 = python2 +PYTHON3 = python3 CHECK = sparse CHECKFLAGS := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \ @@ -430,7 +431,7 @@ GCC_PLUGINS_CFLAGS := export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC export CPP AR NM STRIP OBJCOPY OBJDUMP HOSTLDFLAGS HOST_LOADLIBES -export MAKE LEX YACC AWK GENKSYMS INSTALLKERNEL PERL PYTHON UTS_MACHINE +export MAKE LEX YACC AWK GENKSYMS INSTALLKERNEL PERL PYTHON2 PYTHON3 UTS_MACHINE export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS diff --git a/arch/ia64/Makefile b/arch/ia64/Makefile index 2dd7f51..862a2ba 100644 --- a/arch/ia64/Makefile +++ b/arch/ia64/Makefile @@ -75,7 +75,7 @@ vmlinux.gz: vmlinux $(Q)$(MAKE) $(build)=$(boot) $@ unwcheck: vmlinux - -$(Q)READELF=$(READELF) $(PYTHON) $(srctree)/arch/ia64/scripts/unwcheck.py $< + -$(Q)READELF=$(READELF) $(PYTHON2) $(srctree)/arch/ia64/scripts/unwcheck.py $< archclean: $(Q)$(MAKE) $(clean)=$(boot)
The variable 'PYTHON' allows users to specify a proper executable name in case the default 'python' does not work. However, this does not address the case where both Python 2 and Python 3 scripts are used in one system. PEP 394 (https://www.python.org/dev/peps/pep-0394/) provides a convention for Python scripts portability. Here is a quotation: In order to tolerate differences across platforms, all new code that needs to invoke the Python interpreter should not specify 'python', but rather should specify either 'python2' or 'python3'. This distinction should be made in shebangs, when invoking from a shell script, when invoking via the system() call, or when invoking in any other context. arch/ia64/scripts/unwcheck.py is apparently written in Python 2, so it should be invoked by 'python2'. It is legitimate to use 'python' for scripts compatible with both Python 2 and Python 3, but this is rare (at least I do not see the case in kernel tree). You do not need to make efforts to write your scripts in that way. Anyway, Python 2 will retire in 2020. This commit is needed for my new scripts written in Python 3. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> --- Makefile | 5 +++-- arch/ia64/Makefile | 2 +- 2 files changed, 4 insertions(+), 3 deletions(-)