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From: Junio C Hamano <gitster@pobox.com>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: git@vger.kernel.org, "Jeff King" <peff@peff.net>,
	"Andreas Färber" <andreas.faerber@web.de>,
	"Johannes Schindelin" <Johannes.Schindelin@gmx.de>
Subject: Re: [PATCH 1/6] Makefile: symlink the same way under "symlinks" and "no hardlinks"
Date: Mon, 29 Mar 2021 15:17:34 -0700	[thread overview]
Message-ID: <xmqq1rbxiozl.fsf@gitster.g> (raw)
In-Reply-To: <patch-1.7-39926acb0d1-20210329T162327Z-avarab@gmail.com> (=?utf-8?B?IsOGdmFyCUFybmZqw7Zyw7A=?= Bjarmason"'s message of "Mon, 29 Mar 2021 18:31:39 +0200")

Ævar Arnfjörð Bjarmason  <avarab@gmail.com> writes:

> In particular INSTALL_SYMLINKS=Y will result in a link tree like:
>
>     bin/git
>     libexec/git -> ../bin/git
>     libexec/git-add -> ../bin/git
>
> Whereas NO_INSTALL_HARDLINKS=Y in cases where the "ln" would fail would result in:
>
>     bin/git
>     libexec/git
>     libexec/git-add -> git
>
> I.e. we duplicated the "git" between the bin/ and libexec/
> directories (by default they're hardlinked), and potentially had had
> e.g. "git-add" pointing at the libexec/git hardlink (or more likely if
> "ln" is failing, a copy), instead of the bin/git.
>
> Now we'll instead use the same symlinks to point to the bindir. I
> don't see any reason not to do so, and no breakage related to this has
> been reported with INSTALL_SYMLINKS in all this time. I just did it
> this way to maintain bug-for-bug compatibility at the time.

Makes sense.  I do not see a reason why libexec/git-add that points
at ../bin/git would cause problems, either.

> +# Define NO_INSTALL_HARDLINKS if you'd like to have programs in bin/
> +# and libexec/ either symlinked (we try with INSTALL_SYMLINKS first),
> +# or if that fails fall back on a "cp" instead of a "ln". Useful for
> +# when you don't want hardlinks at all.

So without INSTALL_SYMLINKS and with NO_INSTALL_HARDLINKS, the only
remaining choice is "cp".  With both set, we favour "ln -s" over
"cp" and do not allow "ln".  With INSTALL_SYMLINKS and without
NO_INSTALL_HARDLINKS, we try "ln -s", "ln" and finally "cp".  With
neither, we try "ln" and fall back to "cp"?

That precedence order does make sense.

> @@ -3019,33 +3020,30 @@ endif
>  	} && \
>  	for p in $(filter $(install_bindir_programs),$(BUILT_INS)); do \
>  		$(RM) "$$bindir/$$p" && \
> -		test -n "$(INSTALL_SYMLINKS)" && \
> +		test -n "$(INSTALL_SYMLINKS)" -o "$(NO_INSTALL_HARDLINKS)" && \

I had an impression that we avoid -o/-a used with "test" (instead
we'd use "test && test" or "test || test")?

In either case, if we are told to favor "ln -s", or told not to use
"ln", we try "ln -s"?  That does not make much sense to me, though.

What do I need to do if I do not ever want symbolic links?  Is it
impossible now?

>  		ln -s "git$X" "$$bindir/$$p" || \
>  		{ test -z "$(NO_INSTALL_HARDLINKS)" && \
>  		  ln "$$bindir/git$X" "$$bindir/$$p" 2>/dev/null || \
> -		  ln -s "git$X" "$$bindir/$$p" 2>/dev/null || \
>  		  cp "$$bindir/git$X" "$$bindir/$$p" || exit; }; \
>  	done && \
>  	for p in $(BUILT_INS); do \
>  		$(RM) "$$execdir/$$p" && \
>  		if test -z "$(SKIP_DASHED_BUILT_INS)"; \
>  		then \
> -			test -n "$(INSTALL_SYMLINKS)" && \
> +			test -n "$(INSTALL_SYMLINKS)" -o "$(NO_INSTALL_HARDLINKS)" && \

Perhaps the same comment applies here and to the next hunk, too?

>  			ln -s "$$destdir_from_execdir_SQ/$(bindir_relative_SQ)/git$X" "$$execdir/$$p" || \
>  			{ test -z "$(NO_INSTALL_HARDLINKS)" && \
>  			  ln "$$execdir/git$X" "$$execdir/$$p" 2>/dev/null || \
> -			  ln -s "git$X" "$$execdir/$$p" 2>/dev/null || \
>  			  cp "$$execdir/git$X" "$$execdir/$$p" || exit; }; \
>  		fi \
>  	done && \
>  	remote_curl_aliases="$(REMOTE_CURL_ALIASES)" && \
>  	for p in $$remote_curl_aliases; do \
>  		$(RM) "$$execdir/$$p" && \
> -		test -n "$(INSTALL_SYMLINKS)" && \
> +		test -n "$(INSTALL_SYMLINKS)" -o "$(NO_INSTALL_HARDLINKS)" && \
>  		ln -s "git-remote-http$X" "$$execdir/$$p" || \
>  		{ test -z "$(NO_INSTALL_HARDLINKS)" && \
>  		  ln "$$execdir/git-remote-http$X" "$$execdir/$$p" 2>/dev/null || \
> -		  ln -s "git-remote-http$X" "$$execdir/$$p" 2>/dev/null || \
>  		  cp "$$execdir/git-remote-http$X" "$$execdir/$$p" || exit; } \
>  	done && \
>  	./check_bindir "z$$bindir" "z$$execdir" "$$bindir/git-add$X"

  reply	other threads:[~2021-03-29 22:18 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-07 13:20 [PATCH] Makefile: generate 'git' as 'cc [...] -o git+ && mv git+ git' Ævar Arnfjörð Bjarmason
2021-03-07 20:41 ` Junio C Hamano
2021-03-08 12:38   ` Ævar Arnfjörð Bjarmason
2021-03-08 17:21     ` Junio C Hamano
2021-03-08 18:26     ` Jeff King
2021-03-29 16:20 ` [PATCH v2 0/5] Makefile: don't die on AIX with open ./git Ævar Arnfjörð Bjarmason
2021-03-29 16:20   ` [PATCH v2 1/5] Makefile: rename objects in-place, don't clobber Ævar Arnfjörð Bjarmason
2021-03-29 18:21     ` Junio C Hamano
2021-03-29 18:26       ` Junio C Hamano
2021-03-29 23:24       ` Ævar Arnfjörð Bjarmason
2021-03-30  0:21         ` Junio C Hamano
2021-03-31 14:17           ` Ævar Arnfjörð Bjarmason
2021-03-31 18:50             ` Junio C Hamano
2021-03-29 16:20   ` [PATCH v2 2/5] Makefile: rename scripts " Ævar Arnfjörð Bjarmason
2021-03-29 18:40     ` Junio C Hamano
2021-03-29 23:28       ` Ævar Arnfjörð Bjarmason
2021-03-29 16:20   ` [PATCH v2 3/5] Makefile: don't needlessly "rm $@ $@+" before "mv $@+ $@" Ævar Arnfjörð Bjarmason
2021-03-29 18:46     ` Junio C Hamano
2021-03-29 16:20   ` [PATCH v2 4/5] Makefile: add the ".DELETE_ON_ERROR" flag Ævar Arnfjörð Bjarmason
2021-03-29 18:51     ` Junio C Hamano
2021-03-29 23:31       ` Ævar Arnfjörð Bjarmason
2021-03-29 23:58         ` Junio C Hamano
2021-03-30 15:11         ` Jeff King
2021-03-30 18:36           ` Junio C Hamano
2021-03-31  6:58             ` Jeff King
2021-03-31 18:36               ` Junio C Hamano
2021-03-31 22:29                 ` Johannes Schindelin
2021-03-29 16:20   ` [PATCH v2 5/5] Makefile: don't "rm configure" before generating it Ævar Arnfjörð Bjarmason
2021-03-29 16:31   ` [PATCH 0/6] Makefile: make non-symlink & non-hardlink install sane Ævar Arnfjörð Bjarmason
2021-03-29 16:31     ` [PATCH 1/6] Makefile: symlink the same way under "symlinks" and "no hardlinks" Ævar Arnfjörð Bjarmason
2021-03-29 22:17       ` Junio C Hamano [this message]
2021-03-29 16:31     ` [PATCH 2/6] Makefile: begin refactoring out "ln || ln -s || cp" pattern Ævar Arnfjörð Bjarmason
2021-03-29 22:20       ` Junio C Hamano
2021-03-29 16:31     ` [PATCH 3/6] Makefile: refactor " Ævar Arnfjörð Bjarmason
2021-03-29 22:24       ` Junio C Hamano
2021-03-30 15:20         ` Jeff King
2021-03-30 18:36           ` Junio C Hamano
2021-03-29 16:31     ` [PATCH 4/6] Makefile: make INSTALL_SYMLINKS affect the build directory Ævar Arnfjörð Bjarmason
2021-03-29 22:31       ` Junio C Hamano
2021-03-31 14:04         ` Ævar Arnfjörð Bjarmason
2021-03-29 16:31     ` [PATCH 5/6] Makefile: use "ln -f" instead of "rm && ln" Ævar Arnfjörð Bjarmason
2021-03-29 22:46       ` Junio C Hamano
2021-03-29 16:31     ` [PATCH 6/6] Makefile: add a INSTALL_FALLBACK_LN_CP mode Ævar Arnfjörð Bjarmason
2021-03-29 22:53       ` Junio C Hamano
2021-03-31 14:03         ` Ævar Arnfjörð Bjarmason
2021-03-31 18:45           ` Junio C Hamano
2021-03-31 19:01             ` Ævar Arnfjörð Bjarmason
2021-03-29 23:08     ` [PATCH 0/6] Makefile: make non-symlink & non-hardlink install sane Junio C Hamano

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