Libguestfs - Jun 2019 - [libnbd PATCH] maint: Use $(NULL) for all Makefile.am macro lists

This borrows from a trick in libvirt - by defining $(NULL) to expand
to an empty string, we can more consistently write multi-line macros
where all useful lines terminate with \, making it easier to
add/remove lines without worrying about whether \ needs to be touched
up on neighboring lines.
---

Looks big, but is fairly mechanical.  I'm also doing a similar patch
for nbdkit, where it would have prevented the typo fixed in commit 268e7816.

 Makefile.am                |  6 ++--
 common-rules.mk            |  3 ++
 docs/Makefile.am           |  9 ++++--
 examples/Makefile.am       | 51 ++++++++++++++++++++----------
 generator/Makefile.am      |  6 ++--
 include/Makefile.am        |  3 +-
 interop/Makefile.am        | 24 +++++++++-----
 lib/Makefile.am            | 21 ++++++++----
 ocaml/Makefile.am          | 15 ++++++---
 ocaml/examples/Makefile.am |  3 +-
 sh/Makefile.am             |  3 +-
 tests/Makefile.am          | 65 ++++++++++++++++++++++++--------------
 12 files changed, 139 insertions(+), 70 deletions(-)

diff --git a/Makefile.am b/Makefile.am
index d758378..6a0f4bd 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -22,7 +22,8 @@ ACLOCAL_AMFLAGS = -I m4
 EXTRA_DIST = \
 	.dir-locals.el \
 	.gitignore \
-	html/pod.css
+	html/pod.css \
+	$(NULL)

 SUBDIRS = \
 	generator \
@@ -36,7 +37,8 @@ SUBDIRS = \
 	sh \
 	ocaml \
 	ocaml/examples \
-	interop
+	interop \
+	$(NULL)

 noinst_SCRIPTS = run

diff --git a/common-rules.mk b/common-rules.mk
index 498d221..eb8c92e 100644
--- a/common-rules.mk
+++ b/common-rules.mk
@@ -18,6 +18,9 @@
 # common-rules.mk is included in every Makefile.am.
 # subdir-rules.mk is included only in subdirectories.

+# Convenient list terminator
+NULL +
 CLEANFILES = *~

 $(generator_built): $(top_builddir)/generator/stamp-generator
diff --git a/docs/Makefile.am b/docs/Makefile.am
index f002541..234fff1 100644
--- a/docs/Makefile.am
+++ b/docs/Makefile.am
@@ -18,17 +18,20 @@
 include $(top_srcdir)/subdir-rules.mk

 generator_built = \
-	libnbd-api.pod
+	libnbd-api.pod \
+	$(NULL)

 EXTRA_DIST = \
 	$(generator_built) \
-	libnbd.pod
+	libnbd.pod \
+	$(NULL)

 if HAVE_POD

 man_MANS = \
 	libnbd.3 \
-	libnbd-api.3
+	libnbd-api.3 \
+	$(NULL)
 CLEANFILES += $(man_MANS)

 libnbd.3: libnbd.pod
diff --git a/examples/Makefile.am b/examples/Makefile.am
index b933873..f0d03f1 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -23,42 +23,59 @@ noinst_PROGRAMS = \
 	batched-read-write \
 	simple-fetch-first-sector \
 	simple-reads-and-writes \
-	threaded-reads-and-writes
+	threaded-reads-and-writes \
+	$(NULL)

 simple_fetch_first_sector_SOURCES = \
-	simple-fetch-first-sector.c
+	simple-fetch-first-sector.c \
+	$(NULL)
 simple_fetch_first_sector_CPPFLAGS = \
-	-I$(top_srcdir)/include
+	-I$(top_srcdir)/include \
+	$(NULL)
 simple_fetch_first_sector_CFLAGS = \
-	$(WARNINGS_CFLAGS)
+	$(WARNINGS_CFLAGS) \
+	$(NULL)
 simple_fetch_first_sector_LDADD = \
-	$(top_builddir)/lib/libnbd.la
+	$(top_builddir)/lib/libnbd.la \
+	$(NULL)

 simple_reads_and_writes_SOURCES = \
-	simple-reads-and-writes.c
+	simple-reads-and-writes.c \
+	$(NULL)
 simple_reads_and_writes_CPPFLAGS = \
-	-I$(top_srcdir)/include
+	-I$(top_srcdir)/include \
+	$(NULL)
 simple_reads_and_writes_CFLAGS = \
-	$(WARNINGS_CFLAGS)
+	$(WARNINGS_CFLAGS) \
+	$(NULL)
 simple_reads_and_writes_LDADD = \
-	$(top_builddir)/lib/libnbd.la
+	$(top_builddir)/lib/libnbd.la \
+	$(NULL)

 threaded_reads_and_writes_SOURCES = \
-	threaded-reads-and-writes.c
+	threaded-reads-and-writes.c \
+	$(NULL)
 threaded_reads_and_writes_CPPFLAGS = \
-	-I$(top_srcdir)/include
+	-I$(top_srcdir)/include \
+	$(NULL)
 threaded_reads_and_writes_CFLAGS = \
 	$(WARNINGS_CFLAGS) \
-	$(PTHREAD_CFLAGS)
+	$(PTHREAD_CFLAGS) \
+	$(NULL)
 threaded_reads_and_writes_LDADD = \
 	$(top_builddir)/lib/libnbd.la \
-	$(PTHREAD_LIBS)
+	$(PTHREAD_LIBS) \
+	$(NULL)

 batched_read_write_SOURCES = \
-	batched-read-write.c
+	batched-read-write.c \
+	$(NULL)
 batched_read_write_CPPFLAGS = \
-	-I$(top_srcdir)/include
+	-I$(top_srcdir)/include \
+	$(NULL)
 batched_read_write_CFLAGS = \
-	$(WARNINGS_CFLAGS)
+	$(WARNINGS_CFLAGS) \
+	$(NULL)
 batched_read_write_LDADD = \
-	$(top_builddir)/lib/libnbd.la
+	$(top_builddir)/lib/libnbd.la \
+	$(NULL)
diff --git a/generator/Makefile.am b/generator/Makefile.am
index 4f4e685..c20184a 100644
--- a/generator/Makefile.am
+++ b/generator/Makefile.am
@@ -35,11 +35,13 @@ states_code = \
 	states-oldstyle.c \
 	states-reply-simple.c \
 	states-reply-structured.c \
-	states-reply.c
+	states-reply.c \
+	$(NULL)

 EXTRA_DIST = \
 	generator \
-	$(states_code)
+	$(states_code) \
+	$(NULL)

 if HAVE_OCAML_TOPLEVEL

diff --git a/include/Makefile.am b/include/Makefile.am
index cbeb560..e786447 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -24,4 +24,5 @@ EXTRA_DIST = $(generator_built)
 BUILT_SOURCES = $(generator_built)

 include_HEADERS = \
-	libnbd.h
+	libnbd.h \
+	$(NULL)
diff --git a/interop/Makefile.am b/interop/Makefile.am
index cf36e34..1d2d187 100644
--- a/interop/Makefile.am
+++ b/interop/Makefile.am
@@ -19,7 +19,8 @@ include $(top_srcdir)/subdir-rules.mk

 EXTRA_DIST = \
 	dirty-bitmap.sh \
-	structured-read.sh
+	structured-read.sh \
+	$(NULL)

 TESTS_ENVIRONMENT = LIBNBD_DEBUG=1
 LOG_COMPILER = $(top_builddir)/run
@@ -49,11 +50,13 @@ check_PROGRAMS += \
 	interop-qemu-nbd-tls-certs \
 	interop-qemu-nbd-tls-psk \
 	dirty-bitmap \
-	structured-read
+	structured-read \
+	$(NULL)
 TESTS += \
 	interop-qemu-nbd \
 	dirty-bitmap.sh \
-	structured-read.sh
+	structured-read.sh \
+	$(NULL)

 # tls tests assume the pre-existence of files created in ../tests/Makefile.am,
 # so we can only run them under the same conditions used there
@@ -62,11 +65,13 @@ if HAVE_NBDKIT
 if HAVE_GNUTLS
 if HAVE_CERTTOOL
 TESTS += \
-	interop-qemu-nbd-tls-certs
+	interop-qemu-nbd-tls-certs \
+	$(NULL)
 endif
 if HAVE_PSKTOOL
 TESTS += \
-	interop-qemu-nbd-tls-psk
+	interop-qemu-nbd-tls-psk \
+	$(NULL)
 endif
 endif
 endif
@@ -77,7 +82,8 @@ interop_qemu_nbd_CPPFLAGS = \
 	-DSERVE_OVER_TCP=1 \
 	-DSERVER=\"$(QEMU_NBD)\" \
 	-DSERVER_PARAMS='"-f", "raw", "-x",
"/", "-p", port_str, tmpfile' \
-	-DEXPORT_NAME='"/"'
+	-DEXPORT_NAME='"/"' \
+	$(NULL)
 interop_qemu_nbd_CFLAGS = $(WARNINGS_CFLAGS)
 interop_qemu_nbd_LDADD = $(top_builddir)/lib/libnbd.la

@@ -89,7 +95,8 @@ interop_qemu_nbd_tls_certs_CPPFLAGS = \
 	-DSERVER=\"$(QEMU_NBD)\" \
 	-DSERVER_PARAMS='"--object",
"tls-creds-x509,id=tls0,endpoint=server,dir=$(abs_top_builddir)/tests/pki",
"--tls-creds", "tls0", "-f", "raw",
"-x", "/", "-p", port_str, tmpfile' \
 	-DEXPORT_NAME='"/"' \
-	-DCERTS=1
+	-DCERTS=1 \
+	$(NULL)
 interop_qemu_nbd_tls_certs_CFLAGS = $(WARNINGS_CFLAGS)
 interop_qemu_nbd_tls_certs_LDADD = $(top_builddir)/lib/libnbd.la

@@ -101,7 +108,8 @@ interop_qemu_nbd_tls_psk_CPPFLAGS = \
 	-DSERVER=\"$(QEMU_NBD)\" \
 	-DSERVER_PARAMS='"--object",
"tls-creds-psk,id=tls0,endpoint=server,dir=$(abs_top_builddir)/tests",
"--tls-creds", "tls0", "-f", "raw",
"-x", "/", "-p", port_str, tmpfile' \
 	-DEXPORT_NAME='"/"' \
-	-DPSK=1
+	-DPSK=1 \
+	$(NULL)
 interop_qemu_nbd_tls_psk_CFLAGS = $(WARNINGS_CFLAGS)
 interop_qemu_nbd_tls_psk_LDADD = $(top_builddir)/lib/libnbd.la

diff --git a/lib/Makefile.am b/lib/Makefile.am
index 72d2d0b..7939375 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -21,11 +21,13 @@ generator_built = \
 	api.c \
 	states.c \
 	states.h \
-	unlocked.h
+	unlocked.h \
+	$(NULL)

 EXTRA_DIST = \
 	$(generator_built) \
-	libnbd.syms
+	libnbd.syms \
+	$(NULL)

 lib_LTLIBRARIES = libnbd.la

@@ -51,22 +53,27 @@ libnbd_la_SOURCES = \
 	states.c \
 	states.h \
 	unlocked.h \
-	utils.c
+	utils.c \
+	$(NULL)
 libnbd_la_CPPFLAGS = \
 	-I$(top_srcdir)/include \
-	-Dsysconfdir=\"$(sysconfdir)\"
+	-Dsysconfdir=\"$(sysconfdir)\" \
+	$(NULL)
 libnbd_la_CFLAGS = \
 	$(WARNINGS_CFLAGS) \
 	$(PTHREAD_CFLAGS) \
 	$(GNUTLS_CFLAGS) \
-	$(LIBXML2_CFLAGS)
+	$(LIBXML2_CFLAGS) \
+	$(NULL)
 libnbd_la_LIBADD = \
 	$(GNUTLS_LIBS) \
-	$(LIBXML2_LIBS)
+	$(LIBXML2_LIBS) \
+	$(NULL)
 libnbd_la_LDFLAGS = \
 	$(PTHREAD_LIBS) \
 	-Wl,--version-script=$(srcdir)/libnbd.syms \
-	-version-info 0:0:0
+	-version-info 0:0:0 \
+	$(NULL)

 # pkg-config / pkgconf

diff --git a/ocaml/Makefile.am b/ocaml/Makefile.am
index 0d876bb..bae9e58 100644
--- a/ocaml/Makefile.am
+++ b/ocaml/Makefile.am
@@ -20,10 +20,12 @@ include $(top_srcdir)/subdir-rules.mk
 generator_built = \
 	NBD.mli \
 	NBD.ml \
-	nbd-c.c
+	nbd-c.c \
+	$(NULL)

 EXTRA_DIST = \
-	$(generator_built)
+	$(generator_built) \
+	$(NULL)

 CLEANFILES += *.annot *.cmi *.cmo *.cmx *.o *.a *.so

@@ -71,18 +73,21 @@ endif
 libnbdocaml_a_CPPFLAGS = \
 	-I$(top_builddir) -I$(OCAMLLIB) -I$(top_srcdir)/ocaml \
 	-I$(top_srcdir)/include \
-	-DCAML_NAME_SPACE
+	-DCAML_NAME_SPACE \
+	$(NULL)

 libnbdocaml_a_CFLAGS = \
 	$(WARNINGS_CFLAGS) \
-	-fPIC
+	-fPIC \
+	$(NULL)

 libnbdocaml_a_SOURCES = \
 	nbd-c.c \
 	nbd-c.h \
 	buffer.c \
 	handle.c \
-	helpers.c
+	helpers.c \
+	$(NULL)

 %.bc: %.cmo mlnbd.cma
 	$(top_builddir)/libtool -dlopen $(top_builddir)/lib/.libs/libnbd.la
--mode=execute \
diff --git a/ocaml/examples/Makefile.am b/ocaml/examples/Makefile.am
index 6488f62..7867e14 100644
--- a/ocaml/examples/Makefile.am
+++ b/ocaml/examples/Makefile.am
@@ -19,7 +19,8 @@ include $(top_srcdir)/subdir-rules.mk

 EXTRA_DIST = \
 	LICENSE-FOR-EXAMPLES \
-	extents.ml
+	extents.ml \
+	$(NULL)

 CLEANFILES += *.annot *.cmi *.cmo *.cmx *.o *.a *.so *.bc *.opt

diff --git a/sh/Makefile.am b/sh/Makefile.am
index 3a30ccc..505f751 100644
--- a/sh/Makefile.am
+++ b/sh/Makefile.am
@@ -20,7 +20,8 @@ include $(top_srcdir)/subdir-rules.mk
 EXTRA_DIST = \
 	nbdsh.pod \
 	examples/LICENSE-FOR-EXAMPLES \
-	examples/hexdump.sh
+	examples/hexdump.sh \
+	$(NULL)

 if HAVE_PYTHON

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 2a0acf0..149f890 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -23,7 +23,8 @@ CLEANFILES += \
 	connect-unix.sock \
 	connect-uri-tcp.pid \
 	connect-uri-unix.pid \
-	connect-uri-unix.sock
+	connect-uri-unix.sock \
+	$(NULL)

 EXTRA_DIST = \
 	aio-parallel.sh \
@@ -35,7 +36,8 @@ EXTRA_DIST = \
 	make-pki.sh \
 	meta-base-allocation.sh \
 	synch-parallel.sh \
-	synch-parallel-tls.sh
+	synch-parallel-tls.sh \
+	$(NULL)

 if HAVE_NBDKIT

@@ -66,9 +68,10 @@ check_PROGRAMS = \
 	aio-parallel \
 	aio-parallel-load \
 	synch-parallel \
-	meta-base-allocation
-#	can-cache-flag
-#	can-not-cache-flag
+	meta-base-allocation \
+#	can-cache-flag \
+#	can-not-cache-flag \
+	$(NULL)

 # Make sure that $srcdir is available to tests.
 # Enable debug in all tests.
@@ -101,9 +104,10 @@ TESTS = \
 	aio-parallel.sh \
 	aio-parallel-load.sh \
 	synch-parallel.sh \
-	meta-base-allocation
-#	can-cache-flag
-#	can-not-cache-flag
+	meta-base-allocation \
+#	can-cache-flag \
+#	can-not-cache-flag \
+	$(NULL)

 errors_SOURCES = errors.c
 errors_CPPFLAGS = -I$(top_srcdir)/include
@@ -132,55 +136,64 @@ read_write_flag_LDADD = $(top_builddir)/lib/libnbd.la

 can_flush_flag_SOURCES = eflags.c
 can_flush_flag_CPPFLAGS = \
-	-I$(top_srcdir)/include -Dflag=can_flush
+	-I$(top_srcdir)/include -Dflag=can_flush \
+	$(NULL)
 can_flush_flag_CFLAGS = $(WARNINGS_CFLAGS)
 can_flush_flag_LDADD = $(top_builddir)/lib/libnbd.la

 can_not_flush_flag_SOURCES = eflags.c
 can_not_flush_flag_CPPFLAGS = \
-	-I$(top_srcdir)/include -Dflag=can_flush -Dvalue=false
+	-I$(top_srcdir)/include -Dflag=can_flush -Dvalue=false \
+	$(NULL)
 can_not_flush_flag_CFLAGS = $(WARNINGS_CFLAGS)
 can_not_flush_flag_LDADD = $(top_builddir)/lib/libnbd.la

 can_fua_flag_SOURCES = eflags.c
 can_fua_flag_CPPFLAGS = \
-	-I$(top_srcdir)/include -Dflag=can_fua -Dvalue=native
+	-I$(top_srcdir)/include -Dflag=can_fua -Dvalue=native \
+	$(NULL)
 can_fua_flag_CFLAGS = $(WARNINGS_CFLAGS)
 can_fua_flag_LDADD = $(top_builddir)/lib/libnbd.la

 can_not_fua_flag_SOURCES = eflags.c
 can_not_fua_flag_CPPFLAGS = \
-	-I$(top_srcdir)/include -Dflag=can_fua -Dvalue=none
+	-I$(top_srcdir)/include -Dflag=can_fua -Dvalue=none \
+	$(NULL)
 can_not_fua_flag_CFLAGS = $(WARNINGS_CFLAGS)
 can_not_fua_flag_LDADD = $(top_builddir)/lib/libnbd.la

 is_rotational_flag_SOURCES = eflags.c
 is_rotational_flag_CPPFLAGS = \
-	-I$(top_srcdir)/include -Dflag=is_rotational
+	-I$(top_srcdir)/include -Dflag=is_rotational \
+	$(NULL)
 is_rotational_flag_CFLAGS = $(WARNINGS_CFLAGS)
 is_rotational_flag_LDADD = $(top_builddir)/lib/libnbd.la

 is_not_rotational_flag_SOURCES = eflags.c
 is_not_rotational_flag_CPPFLAGS = \
-	-I$(top_srcdir)/include -Dflag=is_rotational -Dvalue=false
+	-I$(top_srcdir)/include -Dflag=is_rotational -Dvalue=false \
+	$(NULL)
 is_not_rotational_flag_CFLAGS = $(WARNINGS_CFLAGS)
 is_not_rotational_flag_LDADD = $(top_builddir)/lib/libnbd.la

 can_trim_flag_SOURCES = eflags.c
 can_trim_flag_CPPFLAGS = \
-	-I$(top_srcdir)/include -Dflag=can_trim
+	-I$(top_srcdir)/include -Dflag=can_trim \
+	$(NULL)
 can_trim_flag_CFLAGS = $(WARNINGS_CFLAGS)
 can_trim_flag_LDADD = $(top_builddir)/lib/libnbd.la

 can_not_trim_flag_SOURCES = eflags.c
 can_not_trim_flag_CPPFLAGS = \
-	-I$(top_srcdir)/include -Dflag=can_trim -Dvalue=false
+	-I$(top_srcdir)/include -Dflag=can_trim -Dvalue=false \
+	$(NULL)
 can_not_trim_flag_CFLAGS = $(WARNINGS_CFLAGS)
 can_not_trim_flag_LDADD = $(top_builddir)/lib/libnbd.la

 can_zero_flag_SOURCES = eflags.c
 can_zero_flag_CPPFLAGS = \
-	-I$(top_srcdir)/include -Dflag=can_zero
+	-I$(top_srcdir)/include -Dflag=can_zero \
+	$(NULL)
 can_zero_flag_CFLAGS = $(WARNINGS_CFLAGS)
 can_zero_flag_LDADD = $(top_builddir)/lib/libnbd.la
 # Note: can't test not-zero case because nbdkit emulates zero if the
@@ -188,26 +201,30 @@ can_zero_flag_LDADD = $(top_builddir)/lib/libnbd.la

 can_multi_conn_flag_SOURCES = eflags.c
 can_multi_conn_flag_CPPFLAGS = \
-	-I$(top_srcdir)/include -Dflag=can_multi_conn
+	-I$(top_srcdir)/include -Dflag=can_multi_conn \
+	$(NULL)
 can_multi_conn_flag_CFLAGS = $(WARNINGS_CFLAGS)
 can_multi_conn_flag_LDADD = $(top_builddir)/lib/libnbd.la

 can_not_multi_conn_flag_SOURCES = eflags.c
 can_not_multi_conn_flag_CPPFLAGS = \
-	-I$(top_srcdir)/include -Dflag=can_multi_conn -Dvalue=false
+	-I$(top_srcdir)/include -Dflag=can_multi_conn -Dvalue=false \
+	$(NULL)
 can_not_multi_conn_flag_CFLAGS = $(WARNINGS_CFLAGS)
 can_not_multi_conn_flag_LDADD = $(top_builddir)/lib/libnbd.la

 # Waiting for nbdkit to add support for can_cache.
 #can_cache_flag_SOURCES = eflags.c
 #can_cache_flag_CPPFLAGS = \
-#	-I$(top_srcdir)/include -Dflag=can_cache -Dvalue=native
+#	-I$(top_srcdir)/include -Dflag=can_cache -Dvalue=native \
+#	$(NULL)
 #can_cache_flag_CFLAGS = $(WARNINGS_CFLAGS)
 #can_cache_flag_LDADD = $(top_builddir)/lib/libnbd.la
 #
 #can_not_cache_flag_SOURCES = eflags.c
 #can_not_cache_flag_CPPFLAGS = \
-#	-I$(top_srcdir)/include -Dflag=can_cache -Dvalue=none
+#	-I$(top_srcdir)/include -Dflag=can_cache -Dvalue=none \
+#	$(NULL)
 #can_not_cache_flag_CFLAGS = $(WARNINGS_CFLAGS)
 #can_not_cache_flag_LDADD = $(top_builddir)/lib/libnbd.la

@@ -283,12 +300,14 @@ check_PROGRAMS += \
 	connect-tls-psk \
 	aio-parallel-tls \
 	aio-parallel-load-tls \
-	synch-parallel-tls
+	synch-parallel-tls \
+	$(NULL)
 TESTS += \
 	connect-tls-psk \
 	aio-parallel-tls.sh \
 	aio-parallel-load-tls.sh \
-	synch-parallel-tls.sh
+	synch-parallel-tls.sh \
+	$(NULL)
 check_DATA += keys.psk

 connect_tls_psk_SOURCES = connect-tls.c
-- 
2.20.1

ACK this one too

Thanks :-)

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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