[PATCH v2 2/3] Optionally skip linking/copying the built-ins

["Johannes Schindelin via GitGitGadget" <gitgitgadget@gmail.com>]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

For a long time already, the non-dashed form of the built-ins is the
recommended way to write scripts, i.e. it is better to call `git merge
[...]` than to call `git-merge [...]`.

While Git still supports the dashed form (by hard-linking the `git`
executable to the dashed name in `libexec/git-core/`), in practice, it
is probably almost irrelevant.

In fact, some platforms (such as Windows) only started gaining
meaningful Git support _after_ the dashed form was deprecated, and
therefore one would expect that all this hard-linking is unnecessary on
those platforms.

In addition to that, some programs that are regularly used to assess
disk usage fail to realize that those are hard-links, and heavily
overcount disk usage. Most notably, this was the case with Windows
Explorer up until the last couple of Windows 10 versions.

To save on the time needed to hard-link these dashed commands, and to
eventually stop shipping with those hard-links on Windows, let's
introduce a Makefile knob to skip generating them.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 Makefile | 55 +++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 37 insertions(+), 18 deletions(-)

diff --git a/Makefile b/Makefile
index 66b6e076e2..0a09146fb3 100644
--- a/Makefile
+++ b/Makefile
@@ -348,6 +348,9 @@ all::
 # Define NO_INSTALL_HARDLINKS if you prefer to use either symbolic links or
 # copies to install built-in git commands e.g. git-cat-file.
 #
+# Define SKIP_DASHED_BUILT_INS if you do not need the dashed versions of the
+# built-ins to be linked/copied at all.
+#
 # Define USE_NED_ALLOCATOR if you want to replace the platforms default
 # memory allocators with the nedmalloc allocator written by Niall Douglas.
 #
@@ -775,6 +778,16 @@ BUILT_INS += git-whatchanged$X
 # what 'all' will build and 'install' will install in gitexecdir,
 # excluding programs for built-in commands
 ALL_PROGRAMS = $(PROGRAMS) $(SCRIPTS)
+ALL_COMMANDS_TO_INSTALL = $(ALL_PROGRAMS)
+ifeq (,$(SKIP_DASHED_BUILT_INS))
+ALL_COMMANDS_TO_INSTALL += $(BUILT_INS)
+else
+# git-upload-pack, git-receive-pack and git-upload-archive are special: they
+# are _expected_ to be present in the `bin/` directory in their dashed form.
+ALL_COMMANDS_TO_INSTALL += git-receive-pack$(X)
+ALL_COMMANDS_TO_INSTALL += git-upload-archive$(X)
+ALL_COMMANDS_TO_INSTALL += git-upload-pack$(X)
+endif
 
 # what 'all' will build but not install in gitexecdir
 OTHER_PROGRAMS = git$X
@@ -2066,9 +2079,9 @@ profile-fast: profile-clean
 	$(MAKE) PROFILE=USE all
 
 
-all:: $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS) $(OTHER_PROGRAMS) GIT-BUILD-OPTIONS
+all:: $(ALL_COMMANDS_TO_INSTALL) $(SCRIPT_LIB) $(OTHER_PROGRAMS) GIT-BUILD-OPTIONS
 ifneq (,$X)
-	$(QUIET_BUILT_IN)$(foreach p,$(patsubst %$X,%,$(filter %$X,$(ALL_PROGRAMS) $(BUILT_INS) git$X)), test -d '$p' -o '$p' -ef '$p$X' || $(RM) '$p';)
+	$(QUIET_BUILT_IN)$(foreach p,$(patsubst %$X,%,$(filter %$X,$(ALL_COMMANDS_TO_INSTALL) git$X)), test -d '$p' -o '$p' -ef '$p$X' || $(RM) '$p';)
 endif
 
 all::
@@ -2928,7 +2941,7 @@ ifndef NO_TCLTK
 	$(MAKE) -C git-gui gitexecdir='$(gitexec_instdir_SQ)' install
 endif
 ifneq (,$X)
-	$(foreach p,$(patsubst %$X,%,$(filter %$X,$(ALL_PROGRAMS) $(BUILT_INS) git$X)), test '$(DESTDIR_SQ)$(gitexec_instdir_SQ)/$p' -ef '$(DESTDIR_SQ)$(gitexec_instdir_SQ)/$p$X' || $(RM) '$(DESTDIR_SQ)$(gitexec_instdir_SQ)/$p';)
+	$(foreach p,$(patsubst %$X,%,$(filter %$X,$(ALL_COMMANDS_TO_INSTALL) git$X)), test '$(DESTDIR_SQ)$(gitexec_instdir_SQ)/$p' -ef '$(DESTDIR_SQ)$(gitexec_instdir_SQ)/$p$X' || $(RM) '$(DESTDIR_SQ)$(gitexec_instdir_SQ)/$p';)
 endif
 
 	bindir=$$(cd '$(DESTDIR_SQ)$(bindir_SQ)' && pwd) && \
@@ -2946,21 +2959,27 @@ endif
 	} && \
 	for p in $(filter $(install_bindir_programs),$(BUILT_INS)); do \
 		$(RM) "$$bindir/$$p" && \
-		test -n "$(INSTALL_SYMLINKS)" && \
-		ln -s "git$X" "$$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/$$p" || exit; } \
+		if test -z "$(SKIP_DASHED_BUILT_INS)"; \
+		then \
+			test -n "$(INSTALL_SYMLINKS)" && \
+			ln -s "git$X" "$$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/$$p" || exit; }; \
+		fi \
 	done && \
 	for p in $(BUILT_INS); do \
 		$(RM) "$$execdir/$$p" && \
-		test -n "$(INSTALL_SYMLINKS)" && \
-		ln -s "$$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; } \
+		if test -z "$(SKIP_DASHED_BUILT_INS)"; \
+		then \
+			test -n "$(INSTALL_SYMLINKS)" && \
+			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 \
@@ -3051,7 +3070,7 @@ ifneq ($(INCLUDE_DLLS_IN_ARTIFACTS),)
 OTHER_PROGRAMS += $(shell echo *.dll t/helper/*.dll)
 endif
 
-artifacts-tar:: $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS) $(OTHER_PROGRAMS) \
+artifacts-tar:: $(ALL_COMMANDS_TO_INSTALL) $(SCRIPT_LIB) $(OTHER_PROGRAMS) \
 		GIT-BUILD-OPTIONS $(TEST_PROGRAMS) $(test_bindir_programs) \
 		$(MOFILES)
 	$(QUIET_SUBDIR0)templates $(QUIET_SUBDIR1) \
@@ -3146,7 +3165,7 @@ endif
 
 ### Check documentation
 #
-ALL_COMMANDS = $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS)
+ALL_COMMANDS = $(ALL_COMMANDS_TO_INSTALL) $(SCRIPT_LIB)
 ALL_COMMANDS += git
 ALL_COMMANDS += git-citool
 ALL_COMMANDS += git-gui
@@ -3186,7 +3205,7 @@ check-docs::
 		    -e 's/\.txt//'; \
 	) | while read how cmd; \
 	do \
-		case " $(patsubst %$X,%,$(ALL_COMMANDS) $(EXCLUDED_PROGRAMS)) " in \
+		case " $(patsubst %$X,%,$(ALL_COMMANDS) $(BUILT_INS) $(EXCLUDED_PROGRAMS)) " in \
 		*" $$cmd "*)	;; \
 		*) echo "removed but $$how: $$cmd" ;; \
 		esac; \
-- 
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