From 8ae556b8d341bb73d862f5af6a2b70e05fae3a4c Mon Sep 17 00:00:00 2001
From: Rob Browning <rlb@defaultvalue.org>
Date: Sat, 21 Mar 2015 14:32:30 -0500
Subject: [PATCH] Only build _version.py once; remove phony targets

Previously _version.py was a phony target because we couldn't easily
tell when the current git working tree version had changed.  This caused
various targets to be rebuilt multiple times (i.e. recursive make
invocations, etc.).

To fix that, just update _version.py once (at startup) if needed, via an
immediate variable assignment that calls a new ./configure-version
command, i.e.

  initial_setup := $(shell ./configure-version --update)

Signed-off-by: Rob Browning <rlb@defaultvalue.org>
Tested-by: Rob Browning <rlb@defaultvalue.org>
---
 Makefile          | 14 +++++---------
 configure-version | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 9 deletions(-)
 create mode 100755 configure-version

diff --git a/Makefile b/Makefile
index 5bc3bcc..1189613 100644
--- a/Makefile
+++ b/Makefile
@@ -17,6 +17,7 @@ else
   test_tmp := $(CURDIR)/t/tmp
 endif
 
+initial_setup := $(shell ./configure-version --update)
 bup_deps := bup lib/bup/_version.py lib/bup/_helpers$(SOEXT) cmds
 
 all: $(bup_deps) Documentation/all $(current_sampledata)
@@ -82,15 +83,10 @@ lib/bup/_helpers$(SOEXT): \
 	LDFLAGS="$(LDFLAGS)" CFLAGS="$(CFLAGS)" $(PYTHON) csetup.py build
 	cp lib/bup/build/*/_helpers$(SOEXT) lib/bup/
 
-# This must be completely atomic since it may be run (often) in
-# parallel when "-j" is specified, either via targets here, or via
-# tests that use an install tree as data.
-.PHONY: lib/bup/_version.py
 lib/bup/_version.py:
-	rm -f $@.tmp-$$$$ \
-	&& ./format-subst.pl $@.pre > $@.tmp-$$$$ \
-	&& (if ! test -e $@ || ! cmp $@ $@.tmp-$$$$; then mv $@.tmp-$$$$ $@; fi) \
-	&& rm -f $@.tmp-$$$$
+	@echo "Something has gone wrong; $@ should already exist."
+	@echo 'Check "./configure-version --update"'
+	@false
 
 t/tmp:
 	mkdir t/tmp
@@ -185,7 +181,6 @@ clean: Documentation/clean config/clean
 		.*~ *~ */*~ lib/*/*~ lib/*/*/*~ \
 		*.pyc */*.pyc lib/*/*.pyc lib/*/*/*.pyc \
 		bup bup-* cmd/bup-* \
-		lib/bup/_version.py lib/bup/_version.py.tmp-* \
 		randomgen memtest \
 		testfs.img lib/bup/t/testfs.img
 	if test -e t/mnt; then t/cleanup-mounts-under t/mnt; fi
@@ -196,4 +191,5 @@ clean: Documentation/clean config/clean
 	  then umount lib/bup/t/testfs || true; fi
 	rm -rf *.tmp *.tmp.meta t/*.tmp lib/*/*/*.tmp build lib/bup/build lib/bup/t/testfs
 	if test -e t/tmp; then t/force-delete t/tmp; fi
+	./configure-version --clean
 	t/configure-sampledata --clean
diff --git a/configure-version b/configure-version
new file mode 100755
index 0000000..87126b7
--- /dev/null
+++ b/configure-version
@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+
+set -eo pipefail
+
+top="$(pwd)"
+vpy=lib/bup/_version.py
+readonly top vpy
+
+usage()
+{
+    echo 'Usage: ./configure-version [--update | --clean]'
+}
+
+if test "$#" -ne 1; then
+    usage 1>&2; exit 1
+fi
+
+case "$1" in
+    --update)
+        rm -f $vpy.tmp-$$
+        ./format-subst.pl $vpy.pre > $vpy.tmp-$$
+        if ! test -e $vpy || ! cmp -s $vpy $vpy.tmp-$$; then
+            mv $vpy.tmp-$$ $vpy;
+        fi
+        rm -f $vpy.tmp-$$
+        ;;
+    --clean)
+	rm -f lib/bup/_version.py lib/bup/_version.pyc lib/bup/_version.py.tmp-*
+        ;;
+    *)
+        usage 1>&2; exit 1
+        ;;
+esac
-- 
2.39.2