Re: [PATCH] Don't write directly to a make target ($@).
From: Jim Meyering <hidden>
Date: 2016-06-15 22:42:27
Subsystem:
kernel build + files below scripts/ (unless maintained elsewhere), the rest · Maintainers:
Nathan Chancellor, Nicolas Schier, Linus Torvalds
Possibly related (same subject, not in this thread)
- 2016-06-15 · [PATCH] Don't write directly to a make target ($@). · Jim Meyering <hidden>
- 2016-06-15 · Re: [PATCH] Don't write directly to a make target ($@). · Junio C Hamano <hidden>
- 2016-06-15 · Re: [PATCH] Don't write directly to a make target ($@). · Timo Hirvonen <hidden>
- 2016-06-15 · Re: [PATCH] Don't write directly to a make target ($@). · Jim Meyering <hidden>
- 2016-06-15 · Re: [PATCH] Don't write directly to a make target ($@). · Jim Meyering <hidden>
Junio C Hamano [off-list ref] wrote:
Jim Meyering [off-list ref] writes:quoted
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.Thanks. Maybe you would want a "make clean" target for them too if you do this. I often use $@+ instead of t$@ so that I can say "rm -f *+" there.quoted
@@ -496,37 +496,43 @@ builtin-help.o: common-cmds.h rm -f $@ && ln git$X $@ common-cmds.h: Documentation/git-*.txt - ./generate-cmdlist.sh > $@ + ./generate-cmdlist.sh > t$@ + mv t$@ $@IOW, like this: common-cmds.h: Documentation/git-*.txt rm -f $@+ $@ ./generate-cmdlist.sh > $@+ mv $@+ $@ clean:: rm -f *+
I've included a revised patch below. I left off the `clean' addition, because I believe "make clean" should not remove wildcard patterns like "*+", on the off-chance that someone uses names like that for files they care about. Besides, in practice, those temporary files are left behind so rarely that they're not a bother, and they're removed again as part of the next build. --------- Subject: [PATCH] Don't write directly to a make target ($@). Update atomically. Otherwise, if make is killed with prejudice, or if the system crashes, you could be left with an up-to-date, yet corrupt generated file. --- Makefile | 34 ++++++++++++++++++++-------------- 1 files changed, 20 insertions(+), 14 deletions(-) 620173525c5075f2056af107a85881d0d50d3a89
diff --git a/Makefile b/Makefile
index dbf19c6..04536f6 100644
--- a/Makefile
+++ b/Makefile@@ -496,37 +496,43 @@ builtin-help.o: common-cmds.h 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 -
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1.3.2