[LTP] [RFC PATCH 1/3] Makefile: Add C header with generated LTP version

[Li Wang]

On Thu, Jul 13, 2023 at 7:57 PM Cyril Hrubis <chrubis@suse.cz> wrote:

> Hi!
> > obviously this is wrong, because $(top_srcdir)/Version (ltp-version.h
> > dependency) is not specified in the top level Makefile (only Version is
> > there). But I'm not sure if it should be changed to
> > $(top_srcdir)/Version.
> >
> > I suppose ltp-version.h should be in include/
>
> Not reall, as long as it's used only in the library it can stay in the
> lib/
>
> > , but here I'm completely lost with dependencies under lib/. My goal
> > is to type make in lib/ and make sure the header is generated
> > (dependencies correctly resolved).
>
> There is another problem as well, currently the Version file is
> generated at the end of the LTP build, that means if you do a git pull
> and make it's not updated until the build has finished.
>
> Also we will have to rebuild tst_test.c each time Version file has been
> rewritten, which actually happens each time make is build in the top
> level directory, which would cause useless rebuilds.
>
> The best I could came up with:
>
> ---
>  lib/.gitignore     |  2 ++
>  lib/Makefile       | 13 +++++++++++++
>  lib/gen_version.sh | 16 ++++++++++++++++
>  3 files changed, 31 insertions(+)
>  create mode 100644 lib/.gitignore
>  create mode 100755 lib/gen_version.sh
>
> diff --git a/lib/.gitignore b/lib/.gitignore
> new file mode 100644
> index 000000000..178867a94
> --- /dev/null
> +++ b/lib/.gitignore
> @@ -0,0 +1,2 @@
> +ltp-version.h
> +cached-version
> diff --git a/lib/Makefile b/lib/Makefile
> index 9b9906f25..371119ede 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -20,6 +20,19 @@ pc_file                      :=
> $(DESTDIR)/$(datarootdir)/pkgconfig/ltp.pc
>
>  INSTALL_TARGETS                := $(pc_file)
>
> +tst_test.o: ltp-version.h
> +
> +ltp-version.h: gen_version
> +
> +MAKE_TARGETS+=gen_version
> +
> +.PHONY: gen_version
> +gen_version:
> +       @echo GEN ltp-version.h
> +       @./gen_version.sh
> +
> +CLEAN_TARGETS+=ltp-version.h cached-version
> +
>  $(pc_file):
>         test -d "$(@D)" || mkdir -p "$(@D)"
>         install -m $(INSTALL_MODE) "$(builddir)/$(@F)" "$@"
> diff --git a/lib/gen_version.sh b/lib/gen_version.sh
> new file mode 100755
> index 000000000..7ecfb9077
> --- /dev/null
> +++ b/lib/gen_version.sh
> @@ -0,0 +1,16 @@
> +#!/bin/sh
> +
> +touch cached-version;
> +
> +if git describe >/dev/null 2>&1; then
> +       VERSION=`git describe`
> +else
> +       VERSION=`cat $(top_srcdir)/VERSION`
> +fi
> +
> +CACHED_VERSION=`cat cached-version`
> +
> +if [ "$CACHED_VERSION" != "$VERSION" ]; then
> +       echo "$VERSION" > cached-version
> +       echo "#define LTP_VERSION \"$VERSION\"" > ltp-version.h
>


What we are doing in those efforts is to have an available macro
LTP_VERSION, right?

So why not use the script to append that one line in tst_test.h directly?
The ltp-version.h looks quite redundant and we could even put this script
into build.sh together, IMHO.


-- 
Regards,
Li Wang