[RFC/PATCH 5/5] Makefile: Add a NO_INSTALL_BUILTIN_EXECDIR_ALIASES flag

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Back when git was initially written the likes of "git-add", "git-init"
etc. were installed in the user's $PATH. A few years later everything,
with a few exceptions like git-upload-pack and git-receive-pack, was
expected to be invoked as "git $cmd".

Now something like a decade later we're still installing these old
commands in gitexecdir. This is so someone with a shellscript that
still targets e.g. "git-init" can add $(git --exec-path) to their
$PATH and not have to change their script.

Let's add an option to break this backwards compatibility. Now with
NO_INSTALL_BUILTIN_EXECDIR_ALIASES=YesPlease there's only 3 programs
in the bindir that are hardlinked to "git" (receive-pack,
upload-archive & upload-pack), and 3 in the
gitexecdir (git-remote-{ftp,ftps,https} linked to git-remote-http).

There's no cross-directory links anymore, so the
"NO_CROSS_DIRECTORY_HARDLINKS" flag becomes redundant under this new
option.

1. https://public-inbox.org/git/87woyfdkoi.fsf@evledraar.gmail.com/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 Makefile         |  8 ++++++++
 install_programs | 36 +++++++++++++++++++++---------------
 2 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/Makefile b/Makefile
index 07c8b74353..a849a7b6d1 100644
--- a/Makefile
+++ b/Makefile
@@ -346,6 +346,13 @@ all::
 # INSTALL_SYMLINKS if you'd prefer not to have the install procedure
 # fallack on hardlinking or copying if "ln -s" fails.
 #
+# Define NO_INSTALL_BUILTIN_EXECDIR_ALIASES if you'd like to skip
+# installing legacy such as "git-init" and "git-add" in the
+# gitexecdir. Unless you're on a system where "which git-init" is
+# expected to returns something set this. Users have been expected to
+# use the likes of "git init" for ages now, these programs were only
+# provided for legacy compatibility.
+#
 # Define NO_CROSS_DIRECTORY_HARDLINKS if you plan to distribute the installed
 # programs as a tar, where bin/ and libexec/ might be on different file systems.
 #
@@ -2823,6 +2830,7 @@ endif
 		--flag-no-install-hardlinks="$(NO_INSTALL_HARDLINKS)" \
 		--flag-no-cross-directory-hardlinks="$(NO_CROSS_DIRECTORY_HARDLINKS)" \
 		--flag-no-install-symlinks-fallback="$(NO_INSTALL_SYMLINKS_FALLBACK)" \
+		--flag-no-install-builtin-execdir-aliases="$(NO_INSTALL_BUILTIN_EXECDIR_ALIASES)" \
 		--list-bindir-standalone="git$X $(filter $(install_bindir_programs),$(ALL_PROGRAMS))" \
 		--list-bindir-git-dashed="$(filter $(install_bindir_programs),$(BUILT_INS))" \
 		--list-execdir-git-dashed="$(BUILT_INS)" \
diff --git a/install_programs b/install_programs
index 51e08019dd..8d89cd9984 100755
--- a/install_programs
+++ b/install_programs
@@ -33,6 +33,9 @@ do
 	--flag-no-install-symlinks-fallback=*)
 		NO_INSTALL_SYMLINKS_FALLBACK="${1#--flag-no-install-symlinks-fallback=}"
 		;;
+	--flag-no-install-builtin-execdir-aliases=*)
+		NO_INSTALL_BUILTIN_EXECDIR_ALIASES="${1#--flag-no-install-builtin-execdir-aliases=}"
+		;;
 	--list-bindir-standalone=*)
 		list_bindir_standalone="${1#--list-bindir-standalone=}"
 		;;
@@ -54,7 +57,7 @@ do
 	shift
 done &&
 
-if test "$bindir/" != "$execdir/"
+if test "$bindir/" != "$execdir/" -a -z "$NO_INSTALL_BUILTIN_EXECDIR_ALIASES"
 then
 	for p in $list_bindir_standalone; do
 		$RM "$execdir/$p" &&
@@ -87,20 +90,23 @@ do
 	fi
 done &&
 
-for p in $list_execdir_git_dashed; do
-	$RM "$execdir/$p" &&
-	if test -n "$INSTALL_SYMLINKS" -a -n "$NO_INSTALL_SYMLINKS_FALLBACK"
-	then
-		ln -s "$destdir_from_execdir/$bindir_relative/git$X" "$execdir/$p"
-	else
-		test -n "$INSTALL_SYMLINKS" &&
-		ln -s "$destdir_from_execdir/$bindir_relative/git$X" "$execdir/$p" ||
-		{ test -z "$NO_INSTALL_HARDLINKS" &&
-		  ln "$execdir/git$X" "$execdir/$p" ||
-		  ln -s "git$X" "$execdir/$p" ||
-		  cp "$execdir/git$X" "$execdir/$p" || exit; }
-	fi
-done &&
+if test -z "$NO_INSTALL_BUILTIN_EXECDIR_ALIASES"
+then
+	for p in $list_execdir_git_dashed; do
+		$RM "$execdir/$p" &&
+		if test -n "$INSTALL_SYMLINKS" -a -n "$NO_INSTALL_SYMLINKS_FALLBACK"
+		then
+			ln -s "$destdir_from_execdir/$bindir_relative/git$X" "$execdir/$p"
+		else
+			test -n "$INSTALL_SYMLINKS" &&
+			ln -s "$destdir_from_execdir/$bindir_relative/git$X" "$execdir/$p" ||
+			{ test -z "$NO_INSTALL_HARDLINKS" &&
+			  ln "$execdir/git$X" "$execdir/$p" ||
+			  ln -s "git$X" "$execdir/$p" ||
+			  cp "$execdir/git$X" "$execdir/$p" || exit; }
+		fi
+	done
+fi &&
 
 for p in $list_execdir_curl_aliases; do
 	$RM "$execdir/$p" &&
-- 
2.19.1.930.g4563a0d9d0