Makefile: detect errors in running spatch

The "make coccicheck" target runs spatch against each source
file. But it does so in a for loop, so "make" never sees the
exit code of spatch. Worse, it redirects stderr to a log
file, so the user has no indication of any failure. And then
to top it all off, because we touched the patch file's
mtime, make will refuse to repeat the command because it
think the target is up-to-date.

So for example:

$ make coccicheck SPATCH=does-not-exist
SPATCH contrib/coccinelle/free.cocci
SPATCH contrib/coccinelle/qsort.cocci
SPATCH contrib/coccinelle/xstrdup_or_null.cocci
SPATCH contrib/coccinelle/swap.cocci
SPATCH contrib/coccinelle/strbuf.cocci
SPATCH contrib/coccinelle/object_id.cocci
SPATCH contrib/coccinelle/array.cocci
$ make coccicheck SPATCH=does-not-exist
make: Nothing to be done for 'coccicheck'.

With this patch, you get:

$ make coccicheck SPATCH=does-not-exist
SPATCH contrib/coccinelle/free.cocci
/bin/sh: 4: does-not-exist: not found
Makefile:2338: recipe for target 'contrib/coccinelle/free.cocci.patch' failed
make: *** [contrib/coccinelle/free.cocci.patch] Error 1

It also dumps the log on failure, so any errors from spatch
itself (like syntax errors in our .cocci files) will be seen
by the user.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Makefile b/Makefile
index 76267262c155fa907cc6e806f8eb1ce1108e3a6a..c3001709c782710118edea3b50195bd629229145 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -2329,9 +2329,17 @@ check: common-cmds.h
 C_SOURCES = $(patsubst %.o,%.c,$(C_OBJ))
 %.cocci.patch: %.cocci $(C_SOURCES)
        @echo '    ' SPATCH $<; \
+       ret=0; \
        for f in $(C_SOURCES); do \
-               $(SPATCH) --sp-file $< $$f $(SPATCH_FLAGS); \
-       done >$@ 2>$@.log; \
+               $(SPATCH) --sp-file $< $$f $(SPATCH_FLAGS) || \
+                       { ret=$$?; break; }; \
+       done >$@+ 2>$@.log; \
+       if test $$ret != 0; \
+       then \
+               cat $@.log; \
+               exit 1; \
+       fi; \
+       mv $@+ $@; \
        if test -s $@; \
        then \
                echo '    ' SPATCH result: $@; \