Re: [PATCH v3 3/9] Makefile: have "make pot" not "reset --hard"

>
>
> On Mon, May 23 2022, Jiang Xin wrote:
>
> > From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> >
> > Before commit fc0fd5b23b (Makefile: help gettext tools to cope with our
> > custom PRItime format, 2017-07-20) we'd consider source files as-is
> > with gettext, but because we need to understand PRItime in the same way
> > that gettext itself understands PRIuMAX we'd first check if we had a
> > clean checkout, then munge all of the processed files in-place with
> > "sed", generate "po/git.pot", and then finally "reset --hard" to undo
> > our changes.
> >
> > By generating "pot" snippets in ".build/pot/po" for each source file
> > and rewriting certain source files with PRItime macros to temporary
> > files in ".build/pot/po", we can avoid running "make pot" by altering
> > files in place and doing a "reset --hard" afterwards.
> >
> > This speed of "make pot" is slower than before on an initial run,
> > because we run "xgettext" many times (once per source file), but it
> > can be boosted by parallelization. It is *much* faster for incremental
> > runs, and will allow us to implement related targets in subsequent
> > commits.
> >
> > When the "pot" target was originally added in cd5513a7168 (i18n:
> > Makefile: "pot" target to extract messages marked for translation,
> > 2011-02-22) it behaved like a "normal" target. I.e. we'd skip the
> > re-generation of the po/git.pot if nothing had to be done.
> >
> > Then after po/git.pot was checked in in dce37b66fb0 (l10n: initial
> > git.pot for 1.7.10 upcoming release, 2012-02-13) the target was broken
> > until 1f31963e921 (i18n: treat "make pot" as an explicitly-invoked
> > target, 2014-08-22) when it was made to depend on "FORCE". I.e. the
> > Makefile's dependency resolution inherently can't handle incremental
> > building when the target file may be updated by git (or something else
> > external to "make"). But this case no longer applies, so FORCE is no
> > longer needed.
> >
> > That out of the way, the main logic change here is getting rid of the
> > "reset --hard":
> >
> > We'll generate intermediate ".build/pot/po/%.po" files from "%", which
> > is handy to see at a glance what strings (if any) in a given file are
> > marked for translation:
> >
> >       $ make .build/pot/po/pretty.c.po
> >       [...]
> >       $ cat .build/pot/po/pretty.c.po
> >       #: pretty.c:1051
> >       msgid "unable to parse --pretty format"
> >       msgstr ""
> >       $
> >
> > For these C source files which contain the PRItime macros, we will
> > create temporary munged "*.c" files in a tree in ".build/pot/po"
> > corresponding to our source tree, and have "xgettext" consider those.
> > The rule needs to be careful to "(cd .build/pot/po && ...)", because
> > otherwise the comments in the po/git.pot file wouldn't refer to the
> > correct source locations (they'd be prefixed with ".build/pot/po").
> > These temporary munged "*.c” files will be removed immediately after
> > the corresponding po files are generated, because some development tools
> > cannot ignore the duplicate source files in the ".build" directory
> > according to the ".gitignore" file, and that may cause trouble.
> >
> > The output of the generated po/git.pot file is changed in one minor
> > way: Because we're using msgcat(1) instead of xgettext(1) to
> > concatenate the output we'll now disambiguate where "TRANSLATORS"
> > comments come from, in cases where a message is the same in N files,
> > and either only one has a "TRANSLATORS" comment, or they're
> > different. E.g. for the "Your edited hunk[...]" message we'll now
> > apply this change (comment content elided):
> >
> >       +#. #-#-#-#-#  add-patch.c.po  #-#-#-#-#
> >        #. TRANSLATORS: do not translate [y/n]
> >       [...]
> >       +#. #-#-#-#-#  git-add--interactive.perl.po  #-#-#-#-#
> >        #. TRANSLATORS: do not translate [y/n]
> >       [...]
> >        #: add-patch.c:1253 git-add--interactive.perl:1244
> >        msgid ""
> >        "Your edited hunk does not apply. Edit again (saying \"no\" discards!) [y/n]? "
> >        msgstr ""
> >
> > There are six such changes, and they all make the context more
> > understandable, as msgcat(1) is better at handling these edge cases
> > than xgettext(1)'s previously used "--join-existing" flag.
> >
> > But filenames in the above disambiguation lines of extracted-comments
> > have an extra ".po" extension compared to the filenames at the file
> > locations. While we could rename the intermediate ".build/pot/po/%.po"
> > files without the ".po" extension to use more intuitive filenames in
> > the disambiguation lines of extracted-comments, but that will confuse
> > developer tools with lots of invalid C or other source files in
> > ".build/pot/po" directory.
> >
> > The addition of "--omit-header" option for xgettext makes the "pot"
> > snippets in ".build/pot/po/*.po" smaller. But as we'll see in a
> > subsequent commit this header behavior has been hiding an
> > encoding-related bug from us, so let's carry it forward instead of
> > re-generating it with xgettext(1).
> >
> > The "po/git.pot" file should have a header entry, because a proper
> > header entry will increase the speed of creating a new po file using
> > msginit and set a proper "POT-Creation-Date:" field in the header
> > entry of a "po/XX.po" file. We use xgettext to generate a separate
> > header file at ".build/pot/git.header" from "/dev/null", and use this
> > header to assemble "po/git.pot".
> >
> > Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> > Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
> > Signed-off-by: Junio C Hamano <gitster@pobox.com>
> > ---
> >  .gitignore |  1 +
> >  Makefile   | 80 ++++++++++++++++++++++++++++++++++++++++--------------
> >  2 files changed, 60 insertions(+), 21 deletions(-)
> >
> > diff --git a/.gitignore b/.gitignore
> > index e81de1063a..a452215764 100644
> > --- a/.gitignore
> > +++ b/.gitignore
> > @@ -200,6 +200,7 @@
> >  *.[aos]
> >  *.o.json
> >  *.py[co]
> > +.build/
> >  .depend/
> >  *.gcda
> >  *.gcno
> > diff --git a/Makefile b/Makefile
> > index 46914dcd80..1962999c18 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -569,6 +569,7 @@ INSTALL = install
> >  TCL_PATH = tclsh
> >  TCLTK_PATH = wish
> >  XGETTEXT = xgettext
> > +MSGCAT = msgcat
> >  MSGFMT = msgfmt
> >  CURL_CONFIG = curl-config
> >  GCOV = gcov
> > @@ -2706,6 +2707,7 @@ XGETTEXT_FLAGS = \
> >       --force-po \
> >       --add-comments=TRANSLATORS: \
> >       --msgid-bugs-address="Git Mailing List <git@vger.kernel.org>" \
> > +     --package-name=Git \
> >       --sort-by-file \
> >       --from-code=UTF-8
> >  XGETTEXT_FLAGS_C = $(XGETTEXT_FLAGS) --language=C \
> > @@ -2714,6 +2716,7 @@ XGETTEXT_FLAGS_SH = $(XGETTEXT_FLAGS) --language=Shell \
> >       --keyword=gettextln --keyword=eval_gettextln
> >  XGETTEXT_FLAGS_PERL = $(XGETTEXT_FLAGS) --language=Perl \
> >       --keyword=__ --keyword=N__ --keyword="__n:1,2"
> > +MSGCAT_FLAGS = --sort-by-file
> >  LOCALIZED_C = $(FOUND_C_SOURCES) $(FOUND_H_SOURCES) $(SCALAR_SOURCES) \
> >             $(GENERATED_H)
> >  LOCALIZED_SH = $(SCRIPT_SH)
> > @@ -2726,34 +2729,68 @@ LOCALIZED_SH += t/t0200/test.sh
> >  LOCALIZED_PERL += t/t0200/test.perl
> >  endif
> >
> > -## Note that this is meant to be run only by the localization coordinator
> > -## under a very controlled condition, i.e. (1) it is to be run in a
> > -## Git repository (not a tarball extract), (2) any local modifications
> > -## will be lost.
> > +## We generate intermediate .build/pot/po/%.po files containing a
> > +## extract of the translations we find in each file in the source
> > +## tree. We will assemble them using msgcat to create the final
> > +## "po/git.pot" file.
> > +LOCALIZED_ALL_GEN_PO =
> > +
> > +LOCALIZED_C_GEN_PO = $(LOCALIZED_C:%=.build/pot/po/%.po)
> > +LOCALIZED_ALL_GEN_PO += $(LOCALIZED_C_GEN_PO)
> > +
> > +LOCALIZED_SH_GEN_PO = $(LOCALIZED_SH:%=.build/pot/po/%.po)
> > +LOCALIZED_ALL_GEN_PO += $(LOCALIZED_SH_GEN_PO)
> > +
> > +LOCALIZED_PERL_GEN_PO = $(LOCALIZED_PERL:%=.build/pot/po/%.po)
> > +LOCALIZED_ALL_GEN_PO += $(LOCALIZED_PERL_GEN_PO)
> > +
> >  ## Gettext tools cannot work with our own custom PRItime type, so
> >  ## we replace PRItime with PRIuMAX.  We need to update this to
> >  ## PRIdMAX if we switch to a signed type later.
> > +$(LOCALIZED_C_GEN_PO): .build/pot/po/%.po: %
> > +     $(call mkdir_p_parent_template)
> > +     $(QUIET_XGETTEXT) \
> > +         if grep -q PRItime $<; then \
> > +             (\
> > +                     sed -e 's|PRItime|PRIuMAX|g' <$< \
> > +                             >.build/pot/po/$< && \
> > +                     cd .build/pot/po && \
> > +                     $(XGETTEXT) --omit-header \
> > +                             -o $(@:.build/pot/po/%=%) \
> > +                             $(XGETTEXT_FLAGS_C) $< && \
> > +                     rm $<; \
> > +             ); \
> > +         else \
> > +             $(XGETTEXT) --omit-header \
> > +                     -o $@ $(XGETTEXT_FLAGS_C) $<; \
> > +         fi
> >
> > -po/git.pot: $(GENERATED_H) FORCE
> > -     # All modifications will be reverted at the end, so we do not
> > -     # want to have any local change.
> > -     git diff --quiet HEAD && git diff --quiet --cached
> > +$(LOCALIZED_SH_GEN_PO): .build/pot/po/%.po: %
> > +     $(call mkdir_p_parent_template)
> > +     $(QUIET_XGETTEXT)$(XGETTEXT) --omit-header \
> > +             -o$@ $(XGETTEXT_FLAGS_SH) $<
> >
> > -     @for s in $(LOCALIZED_C) $(LOCALIZED_SH) $(LOCALIZED_PERL); \
> > -     do \
> > -             sed -e 's|PRItime|PRIuMAX|g' <"$$s" >"$$s+" && \
> > -             cat "$$s+" >"$$s" && rm "$$s+"; \
> > -     done
> > +$(LOCALIZED_PERL_GEN_PO): .build/pot/po/%.po: %
> > +     $(call mkdir_p_parent_template)
> > +     $(QUIET_XGETTEXT)$(XGETTEXT) --omit-header \
> > +             -o$@ $(XGETTEXT_FLAGS_PERL) $<
> > +q
> > +define gen_pot_header
> > +$(XGETTEXT) $(XGETTEXT_FLAGS_C) \
> > +     -o - /dev/null | \
> > +sed -e 's|charset=CHARSET|charset=UTF-8|' \
> > +    -e 's|\(Last-Translator: \)FULL NAME <.*>|\1make by the Makefile|' \
> > +    -e 's|\(Language-Team: \)LANGUAGE <.*>|\1Git Mailing List <git@vger.kernel.org>|' \
> > +    >$@ && \
> > +echo '"Plural-Forms: nplurals=INTEGER; plural=EXPRESSION;\\n"' >>$@
> > +endef
> >
> > -     $(QUIET_XGETTEXT)$(XGETTEXT) -o$@+ $(XGETTEXT_FLAGS_C) $(LOCALIZED_C)
> > -     $(QUIET_XGETTEXT)$(XGETTEXT) -o$@+ --join-existing $(XGETTEXT_FLAGS_SH) \
> > -             $(LOCALIZED_SH)
> > -     $(QUIET_XGETTEXT)$(XGETTEXT) -o$@+ --join-existing $(XGETTEXT_FLAGS_PERL) \
> > -             $(LOCALIZED_PERL)
> > +.build/pot/git.header: $(LOCALIZED_ALL_GEN_PO)
> > +     $(call mkdir_p_parent_template)
> > +     $(QUIET_GEN)$(gen_pot_header)
>
> So re a previous round I think the addition of a header to po/git.pot
> doesn't make sense, i.e. it's not needed, so we can just drop this
> entirely.

> If so I think that to the extent we need headers at all (for the *.po
> files) it might be worthwhile to just have the timestamp be the same
> epoch we use for the tests in t/, i.e. never update it and avoid the
> needless churn. If people need to check when things were last changed,
> or initially added, they can use this little thing called "git" :)