Subject: Re: [PATCH v3] diff-highlight: make install link into DESTDIR

From: Đoàn Trần Công Danh <[email-masked]>
Date: Mon, 14 Oct 2024 10:29:23 +0700

On 2024-10-13 01:41:06+0200, immeëmosol <[email-masked]> wrote:
> As mentioned, `contrib/diff-highlight` is less like other perl contribs
> like `contrib/contacts` and `contrib/credential/netrc`, those two seem to
> be git subcommands (`git-*`) where diff-highlight is more of a "standalone"
> command.
> 
> My usecase was to peek at what the command does by making it available in a
> `$PATH` writable by a non-root user. (Much like what is mentioned in
> `contrib/diff-highlight/README#Use`: `git log -p --color | diff-highlight`.=
> )
> 
> ```sh
> echo '# Given ~/.local/bin is in $PATH,'
> ( export DESTDIR=3D"${HOME?}/.local/bin/" ; make linked-in-destdir )
> echo '# In another already open shell, try suggestion from readme.'
> ( export DESTDIR=3D"${HOME?}/.local/bin/" ; make clean )
> ```

Nah, it isn't DESTDIR's usage, it's prefix job!

	make prefix=${HOME}/.local install

> ---
> Make git's diff-highlight program immediately available to the command-line=
> .
> Create a link in DESTDIR that
> refers to the generated/concatenated diff-highlight perl script
> 
> Signed-off-by: imme=C3=ABmosol <[email-masked]>
> ---
>  contrib/diff-highlight/Makefile | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/contrib/diff-highlight/Makefile
> b/contrib/diff-highlight/Makefile
> index f2be7cc9243719..84f6e65c730380 100644
> --- a/contrib/diff-highlight/Makefile
> +++ b/contrib/diff-highlight/Makefile
> @@ -10,6 +10,11 @@ diff-highlight: shebang.perl DiffHighlight.pm
> diff-highlight.perl
>      chmod +x $@+
>      mv $@+ $@
> 
> +linked-in-destdir: diff-highlight
> +    test -n "$(DESTDIR)" && \
> +        test -w $(DESTDIR) && \
> +        ln -s $(abspath $<) $(DESTDIR)

So it would be something like this:

	install: diff-highlight
		$(INSTALL) diff-highlight '$(DESTDIR)$(bindir_SQ)'

> +
>  shebang.perl: FORCE
>      @echo '#!$(PERL_PATH_SQ)' >$@+
>      @cmp $@+ $@ >/dev/null 2>/dev/null || mv $@+ $@
> @@ -17,7 +22,13 @@ shebang.perl: FORCE
>  test: all
>      $(MAKE) -C t
> 
> -clean:
> +unlink-from-destdir:
> +    test -z "$(DESTDIR)" || \
> +        test ! -L $(DESTDIR)/diff-highlight || \
> +        $(RM) $(DESTDIR)/diff-highlight
> +
> +clean: unlink-from-destdir
>      $(RM) diff-highlight
> 
>  .PHONY: FORCE
> +.PHONY: linked-in-destdir unlink-from-destdir
> 

-- 
Danh