Don't write directly to a make target ($@).

Otherwise, if make is suspended, or killed with prejudice, or if the
system crashes, you could be left with an up-to-date, yet corrupt,
generated file.

I left off the `clean' addition, because I believe "make clean" should
not remove wildcard patterns like "*+", on the off-chance that someone
uses names like that for files they care about.  Besides, in practice,
those temporary files are left behind so rarely that they're not a bother,
and they're removed again as part of the next build.

[jc: sign-off?]

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/Makefile b/Makefile
index a07964b..5ad16a0 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -496,37 +496,43 @@ $(BUILT_INS): git$X
        rm -f $@ && ln git$X $@
 
 common-cmds.h: Documentation/git-*.txt
-       ./generate-cmdlist.sh > $@
+       ./generate-cmdlist.sh > $@+
+       mv $@+ $@
 
 $(patsubst %.sh,%,$(SCRIPT_SH)) : % : %.sh
-       rm -f $@
+       rm -f $@ $@+
        sed -e '1s|#!.*/sh|#!$(SHELL_PATH_SQ)|' \
            -e 's/@@GIT_VERSION@@/$(GIT_VERSION)/g' \
            -e 's/@@NO_CURL@@/$(NO_CURL)/g' \
            -e 's/@@NO_PYTHON@@/$(NO_PYTHON)/g' \
-           $@.sh >$@
-       chmod +x $@
+           $@.sh >$@+
+       chmod +x $@+
+       mv $@+ $@
 
 $(patsubst %.perl,%,$(SCRIPT_PERL)) : % : %.perl
-       rm -f $@
+       rm -f $@ $@+
        sed -e '1s|#!.*perl|#!$(PERL_PATH_SQ)|' \
            -e 's/@@GIT_VERSION@@/$(GIT_VERSION)/g' \
-           $@.perl >$@
-       chmod +x $@
+           $@.perl >$@+
+       chmod +x $@+
+       mv $@+ $@
 
 $(patsubst %.py,%,$(SCRIPT_PYTHON)) : % : %.py
-       rm -f $@
+       rm -f $@ $@+
        sed -e '1s|#!.*python|#!$(PYTHON_PATH_SQ)|' \
            -e 's|@@GIT_PYTHON_PATH@@|$(GIT_PYTHON_DIR_SQ)|g' \
            -e 's/@@GIT_VERSION@@/$(GIT_VERSION)/g' \
-           $@.py >$@
-       chmod +x $@
+           $@.py >$@+
+       chmod +x $@+
+       mv $@+ $@
 
 git-cherry-pick: git-revert
-       cp $< $@
+       cp $< $@+
+       mv $@+ $@
 
 git-status: git-commit
-       cp $< $@
+       cp $< $@+
+       mv $@+ $@
 
 # These can record GIT_VERSION
 git$X git.spec \
@@ -653,7 +659,8 @@ install-doc:
 ### Maintainer's dist rules
 
 git.spec: git.spec.in
-       sed -e 's/@@VERSION@@/$(GIT_VERSION)/g' < $< > $@
+       sed -e 's/@@VERSION@@/$(GIT_VERSION)/g' < $< > $@+
+       mv $@+ $@
 
 GIT_TARNAME=git-$(GIT_VERSION)
 dist: git.spec git-tar-tree
@@ -724,4 +731,3 @@ check-docs::
                *) echo "no link: $$v";; \
                esac ; \
        done | sort
-