[PATCH 0/3] fix minor Makefile annoyances

[PATCH 0/3] fix minor Makefile annoyances

[Jeff King]

I've noticed that running "make" on a fully-built git tree still builds
a lot of things:

  $ make >/dev/null 2>&1 && make
      GEN perl/PM.stamp
      SUBDIR gitweb
      GEN git-add--interactive
      GEN git-difftool
      GEN git-archimport
      GEN git-cvsexportcommit
      GEN git-cvsimport
      GEN git-cvsserver
      GEN git-relink
      GEN git-send-email
      GEN git-svn
      GEN git-p4
      SUBDIR ../
  make[2]: 'GIT-VERSION-FILE' is up to date.
      GEN git-instaweb
      SUBDIR perl
      SUBDIR templates

Here it is after this series:

  $ make >/dev/null 2>&1 && make
      SUBDIR perl
      SUBDIR templates

The patches are:

  [1/3]: Makefile: drop dependency between git-instaweb and gitweb
  [2/3]: Makefile: avoid timestamp updates to GIT-BUILD-OPTIONS
  [3/3]: Makefile: silence perl/PM.stamp recipe

-Peff

[PATCH 1/3] Makefile: drop dependency between git-instaweb and gitweb

[Jeff King]

The rule for "git-instaweb" depends on "gitweb". This makes
no sense, because:

  1. git-instaweb has no build-time dependency on gitweb; it
     is a run-time dependency

  2. gitweb is a directory that we want to recursively make
     in. As a result, its recipe is marked .PHONY, which
     causes "make" to rebuild git-instaweb every time it is
     run.

Signed-off-by: Jeff King <peff@peff.net>
---
Note that this actually means we won't build "gitweb" at all with just
"make". It's possible that might break somebody's packaging script that
does:

  make &&
  cp gitweb/gitweb /some/place

I'm not incredibly concerned with that, as it was only being built as a
bizarre side effect here, and they should probably be doing "make
gitweb" (or "cd gitweb && make") if that's what they want to build.

But if we do want to build it by default, we can add it into the "all::"
rule, as we do for "templates".

 Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 323c401..6283353 100644
--- a/Makefile
+++ b/Makefile
@@ -1784,7 +1784,7 @@ GIT-PERL-DEFINES: FORCE
 gitweb:
 	$(QUIET_SUBDIR0)gitweb $(QUIET_SUBDIR1) all
 
-git-instaweb: git-instaweb.sh gitweb GIT-SCRIPT-DEFINES
+git-instaweb: git-instaweb.sh GIT-SCRIPT-DEFINES
 	$(QUIET_GEN)$(cmd_munge_script) && \
 	chmod +x $@+ && \
 	mv $@+ $@
-- 
2.4.2.668.gc3b1ade.dirty

[PATCH 2/3] Makefile: avoid timestamp updates to GIT-BUILD-OPTIONS

[Jeff King]

We force the GIT-BUILD-OPTIONS recipe to run every time
"make" is invoked. We must do this to catch new options
which may have come from the command-line or environment.

However, we actually update the file's timestamp each time
the recipe is run, whether anything changed or not. As a
result, any files which depend on it (for example, all of
the perl scripts, which need to know whether NO_PERL was
set) will be re-built every time.

Let's do our usual trick of writing to a tempfile, then
doing a "cmp || mv" to update the file only when something
changed.

Signed-off-by: Jeff King <peff@peff.net>
---
 Makefile | 45 +++++++++++++++++++++++----------------------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/Makefile b/Makefile
index 6283353..6b4fbeb 100644
--- a/Makefile
+++ b/Makefile
@@ -2103,46 +2103,47 @@ GIT-LDFLAGS: FORCE
 # that runs GIT-BUILD-OPTIONS, and then again to protect it
 # and the first level quoting from the shell that runs "echo".
 GIT-BUILD-OPTIONS: FORCE
-	@echo SHELL_PATH=\''$(subst ','\'',$(SHELL_PATH_SQ))'\' >$@
-	@echo PERL_PATH=\''$(subst ','\'',$(PERL_PATH_SQ))'\' >>$@
-	@echo DIFF=\''$(subst ','\'',$(subst ','\'',$(DIFF)))'\' >>$@
-	@echo PYTHON_PATH=\''$(subst ','\'',$(PYTHON_PATH_SQ))'\' >>$@
-	@echo TAR=\''$(subst ','\'',$(subst ','\'',$(TAR)))'\' >>$@
-	@echo NO_CURL=\''$(subst ','\'',$(subst ','\'',$(NO_CURL)))'\' >>$@
-	@echo NO_EXPAT=\''$(subst ','\'',$(subst ','\'',$(NO_EXPAT)))'\' >>$@
-	@echo USE_LIBPCRE=\''$(subst ','\'',$(subst ','\'',$(USE_LIBPCRE)))'\' >>$@
-	@echo NO_PERL=\''$(subst ','\'',$(subst ','\'',$(NO_PERL)))'\' >>$@
-	@echo NO_PYTHON=\''$(subst ','\'',$(subst ','\'',$(NO_PYTHON)))'\' >>$@
-	@echo NO_UNIX_SOCKETS=\''$(subst ','\'',$(subst ','\'',$(NO_UNIX_SOCKETS)))'\' >>$@
+	@echo SHELL_PATH=\''$(subst ','\'',$(SHELL_PATH_SQ))'\' >$@+
+	@echo PERL_PATH=\''$(subst ','\'',$(PERL_PATH_SQ))'\' >>$@+
+	@echo DIFF=\''$(subst ','\'',$(subst ','\'',$(DIFF)))'\' >>$@+
+	@echo PYTHON_PATH=\''$(subst ','\'',$(PYTHON_PATH_SQ))'\' >>$@+
+	@echo TAR=\''$(subst ','\'',$(subst ','\'',$(TAR)))'\' >>$@+
+	@echo NO_CURL=\''$(subst ','\'',$(subst ','\'',$(NO_CURL)))'\' >>$@+
+	@echo NO_EXPAT=\''$(subst ','\'',$(subst ','\'',$(NO_EXPAT)))'\' >>$@+
+	@echo USE_LIBPCRE=\''$(subst ','\'',$(subst ','\'',$(USE_LIBPCRE)))'\' >>$@+
+	@echo NO_PERL=\''$(subst ','\'',$(subst ','\'',$(NO_PERL)))'\' >>$@+
+	@echo NO_PYTHON=\''$(subst ','\'',$(subst ','\'',$(NO_PYTHON)))'\' >>$@+
+	@echo NO_UNIX_SOCKETS=\''$(subst ','\'',$(subst ','\'',$(NO_UNIX_SOCKETS)))'\' >>$@+
 ifdef TEST_OUTPUT_DIRECTORY
-	@echo TEST_OUTPUT_DIRECTORY=\''$(subst ','\'',$(subst ','\'',$(TEST_OUTPUT_DIRECTORY)))'\' >>$@
+	@echo TEST_OUTPUT_DIRECTORY=\''$(subst ','\'',$(subst ','\'',$(TEST_OUTPUT_DIRECTORY)))'\' >>$@+
 endif
 ifdef GIT_TEST_OPTS
-	@echo GIT_TEST_OPTS=\''$(subst ','\'',$(subst ','\'',$(GIT_TEST_OPTS)))'\' >>$@
+	@echo GIT_TEST_OPTS=\''$(subst ','\'',$(subst ','\'',$(GIT_TEST_OPTS)))'\' >>$@+
 endif
 ifdef GIT_TEST_CMP
-	@echo GIT_TEST_CMP=\''$(subst ','\'',$(subst ','\'',$(GIT_TEST_CMP)))'\' >>$@
+	@echo GIT_TEST_CMP=\''$(subst ','\'',$(subst ','\'',$(GIT_TEST_CMP)))'\' >>$@+
 endif
 ifdef GIT_TEST_CMP_USE_COPIED_CONTEXT
-	@echo GIT_TEST_CMP_USE_COPIED_CONTEXT=YesPlease >>$@
+	@echo GIT_TEST_CMP_USE_COPIED_CONTEXT=YesPlease >>$@+
 endif
-	@echo NO_GETTEXT=\''$(subst ','\'',$(subst ','\'',$(NO_GETTEXT)))'\' >>$@
-	@echo GETTEXT_POISON=\''$(subst ','\'',$(subst ','\'',$(GETTEXT_POISON)))'\' >>$@
+	@echo NO_GETTEXT=\''$(subst ','\'',$(subst ','\'',$(NO_GETTEXT)))'\' >>$@+
+	@echo GETTEXT_POISON=\''$(subst ','\'',$(subst ','\'',$(GETTEXT_POISON)))'\' >>$@+
 ifdef GIT_PERF_REPEAT_COUNT
-	@echo GIT_PERF_REPEAT_COUNT=\''$(subst ','\'',$(subst ','\'',$(GIT_PERF_REPEAT_COUNT)))'\' >>$@
+	@echo GIT_PERF_REPEAT_COUNT=\''$(subst ','\'',$(subst ','\'',$(GIT_PERF_REPEAT_COUNT)))'\' >>$@+
 endif
 ifdef GIT_PERF_REPO
-	@echo GIT_PERF_REPO=\''$(subst ','\'',$(subst ','\'',$(GIT_PERF_REPO)))'\' >>$@
+	@echo GIT_PERF_REPO=\''$(subst ','\'',$(subst ','\'',$(GIT_PERF_REPO)))'\' >>$@+
 endif
 ifdef GIT_PERF_LARGE_REPO
-	@echo GIT_PERF_LARGE_REPO=\''$(subst ','\'',$(subst ','\'',$(GIT_PERF_LARGE_REPO)))'\' >>$@
+	@echo GIT_PERF_LARGE_REPO=\''$(subst ','\'',$(subst ','\'',$(GIT_PERF_LARGE_REPO)))'\' >>$@+
 endif
 ifdef GIT_PERF_MAKE_OPTS
-	@echo GIT_PERF_MAKE_OPTS=\''$(subst ','\'',$(subst ','\'',$(GIT_PERF_MAKE_OPTS)))'\' >>$@
+	@echo GIT_PERF_MAKE_OPTS=\''$(subst ','\'',$(subst ','\'',$(GIT_PERF_MAKE_OPTS)))'\' >>$@+
 endif
 ifdef TEST_GIT_INDEX_VERSION
-	@echo TEST_GIT_INDEX_VERSION=\''$(subst ','\'',$(subst ','\'',$(TEST_GIT_INDEX_VERSION)))'\' >>$@
+	@echo TEST_GIT_INDEX_VERSION=\''$(subst ','\'',$(subst ','\'',$(TEST_GIT_INDEX_VERSION)))'\' >>$@+
 endif
+	@if cmp $@+ $@ >/dev/null 2>&1; then $(RM) $@+; else mv $@+ $@; fi
 
 ### Detect Python interpreter path changes
 ifndef NO_PYTHON
-- 
2.4.2.668.gc3b1ade.dirty

[PATCH 3/3] Makefile: silence perl/PM.stamp recipe

[Jeff King]

Every time we run "make", we update perl/PM.stamp, which
contains a list of all of the perl module files (if it's
updated, we need to rebuild perl/perl.mak, since the
Makefile will not otherwise know about the new files).

This means that every time "make" is run, we see:

      GEN perl/PM.stamp

in the output, even though it is not likely to have changed.
Let's make this recipe completely silent, as we do for other
auto-generated dependency files (e.g., GIT-CFLAGS).

Signed-off-by: Jeff King <peff@peff.net>
---
 Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 6b4fbeb..6b0dd47 100644
--- a/Makefile
+++ b/Makefile
@@ -1747,7 +1747,7 @@ $(SCRIPT_PERL_GEN): perl/perl.mak
 perl/perl.mak: perl/PM.stamp
 
 perl/PM.stamp: FORCE
-	$(QUIET_GEN)$(FIND) perl -type f -name '*.pm' | sort >$@+ && \
+	@$(FIND) perl -type f -name '*.pm' | sort >$@+ && \
 	{ cmp $@+ $@ >/dev/null 2>/dev/null || mv $@+ $@; } && \
 	$(RM) $@+
 
-- 
2.4.2.668.gc3b1ade.dirty