Makefiles: add "shared.mak", move ".DELETE_ON_ERROR" to it

We have various behavior that's shared across our Makefiles, or that
really should be (e.g. via defined templates). Let's create a
top-level "shared.mak" to house those sorts of things, and start by
adding the ".DELETE_ON_ERROR" flag to it.

See my own 7b76d6bf221 (Makefile: add and use the ".DELETE_ON_ERROR"
flag, 2021-06-29) and db10fc6c09f (doc: simplify Makefile using
.DELETE_ON_ERROR, 2021-05-21) for the addition and use of the
".DELETE_ON_ERROR" flag.

I.e. this changes the behavior of existing rules in the altered
Makefiles (except "Makefile" & "Documentation/Makefile"). I'm
confident that this is safe having read the relevant rules in those
Makfiles, and as the GNU make manual notes that it isn't the default
behavior is out of an abundance of backwards compatibility
caution. From edition 0.75 of its manual, covering GNU make 4.3:

    [Enabling '.DELETE_ON_ERROR' is] almost always what you want
    'make' to do, but it is not historical practice; so for
    compatibility, you must explicitly request it.

This doesn't introduce a bug by e.g. having this
".DELETE_ON_ERROR" flag only apply to this new shared.mak, Makefiles
have no such scoping semantics.

It does increase the danger that any Makefile without an explicit "The
default target of this Makefile is..." snippet to define the default
target as "all" could have its default rule changed if our new
shared.mak ever defines a "real" rule. In subsequent commits we'll be
careful not to do that, and such breakage would be obvious e.g. in the
case of "make -C t".

We might want to make that less fragile still (e.g. by using
".DEFAULT_GOAL" as noted in the preceding commit), but for now let's
simply include "shared.mak" without adding that boilerplate to all the
Makefiles that don't have it already. Most of those are already
exposed to that potential caveat e.g. due to including "config.mak*".

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/Makefile b/Documentation/Makefile
index ed656db2ae90c1f5e0498867ec170395f6898b1f..ba27456c86a7afc00dfd74e8a6bea82433db88dd 100644 (file)
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -1,3 +1,6 @@
+# Import tree-wide shared Makefile behavior and libraries
+include ../shared.mak
+
 # Guard against environment variables
 MAN1_TXT =
 MAN5_TXT =
@@ -524,7 +527,4 @@ doc-l10n install-l10n::
        $(MAKE) -C po $@
 endif
 
-# Delete the target file on error
-.DELETE_ON_ERROR:
-
 .PHONY: FORCE

diff --git a/Makefile b/Makefile
index 6f0b4b775fece6acd20348e318a8cff3e254bcb2..aa5ff001b6e11cc2f9f3d7866a7187528aeb5bc1 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,9 @@
 # The default target of this Makefile is...
 all::
 
+# Import tree-wide shared Makefile behavior and libraries
+include shared.mak
+
 # Define V=1 to have a more verbose compile.
 #
 # Define SHELL_PATH to a POSIX shell if your /bin/sh is broken.
@@ -2194,16 +2197,6 @@ shell_compatibility_test: please_set_SHELL_PATH_to_a_more_modern_shell
 strip: $(PROGRAMS) git$X
        $(STRIP) $(STRIP_OPTS) $^
 
-### Flags affecting all rules
-
-# A GNU make extension since gmake 3.72 (released in late 1994) to
-# remove the target of rules if commands in those rules fail. The
-# default is to only do that if make itself receives a signal. Affects
-# all targets, see:
-#
-#    info make --index-search=.DELETE_ON_ERROR
-.DELETE_ON_ERROR:
-
 ### Target-specific flags and dependencies
 
 # The generic compilation pattern rule and automatically

diff --git a/contrib/scalar/Makefile b/contrib/scalar/Makefile
index 1e9b969f3df98c4da0142b5c015636a938c81886..d585b319edcd6b1da3151a1759cacd4ebb271396 100644 (file)
--- a/contrib/scalar/Makefile
+++ b/contrib/scalar/Makefile
@@ -1,6 +1,9 @@
 # The default target of this Makefile is...
 all::
 
+# Import tree-wide shared Makefile behavior and libraries
+include ../../shared.mak
+
 include ../../config.mak.uname
 -include ../../config.mak.autogen
 -include ../../config.mak

diff --git a/contrib/scalar/t/Makefile b/contrib/scalar/t/Makefile
index 6170672bb371f98cdb4216591382298b2c0a2dbf..01e82e56d15629abd0444646341c1a9d639fc310 100644 (file)
--- a/contrib/scalar/t/Makefile
+++ b/contrib/scalar/t/Makefile
@@ -1,3 +1,6 @@
+# Import tree-wide shared Makefile behavior and libraries
+include ../../../shared.mak
+
 # Run scalar tests
 #
 # Copyright (c) 2005,2021 Junio C Hamano, Johannes Schindelin

diff --git a/shared.mak b/shared.mak
new file mode 100644 (file)
index 0000000..0170bb3
--- /dev/null
+++ b/shared.mak
@@ -0,0 +1,9 @@
+### Flags affecting all rules
+
+# A GNU make extension since gmake 3.72 (released in late 1994) to
+# remove the target of rules if commands in those rules fail. The
+# default is to only do that if make itself receives a signal. Affects
+# all targets, see:
+#
+#    info make --index-search=.DELETE_ON_ERROR
+.DELETE_ON_ERROR:

diff --git a/t/Makefile b/t/Makefile
index 46cd5fc5273dc0bcb907ab49ce8c97c4783053be..056ce55dcc92c923ce560ef61a0b2888d799c450 100644 (file)
--- a/t/Makefile
+++ b/t/Makefile
@@ -1,3 +1,6 @@
+# Import tree-wide shared Makefile behavior and libraries
+include ../shared.mak
+
 # Run tests
 #
 # Copyright (c) 2005 Junio C Hamano

diff --git a/t/interop/Makefile b/t/interop/Makefile
index 31a4bbc716aa3ad97cdeed1344e852f1dfa04b46..6911c2915a74b16647c0075cabda39d415d2562a 100644 (file)
--- a/t/interop/Makefile
+++ b/t/interop/Makefile
@@ -1,3 +1,6 @@
+# Import tree-wide shared Makefile behavior and libraries
+include ../../shared.mak
+
 -include ../../config.mak
 export GIT_TEST_OPTIONS
 

diff --git a/t/perf/Makefile b/t/perf/Makefile
index 2465770a7825b4f360d649df3684c5339c8ce657..e4808aebed08bfb87d0cc9ab6ccd2a70eee3c84e 100644 (file)
--- a/t/perf/Makefile
+++ b/t/perf/Makefile
@@ -1,3 +1,6 @@
+# Import tree-wide shared Makefile behavior and libraries
+include ../../shared.mak
+
 -include ../../config.mak
 export GIT_TEST_OPTIONS
 

diff --git a/templates/Makefile b/templates/Makefile
index d22a71a3999b3dc0e99f5e36053447b33f967bd7..636cee52f51f9232ffd0b373a97f5d4036bee069 100644 (file)
--- a/templates/Makefile
+++ b/templates/Makefile
@@ -1,3 +1,6 @@
+# Import tree-wide shared Makefile behavior and libraries
+include ../shared.mak
+
 # make and install sample templates
 
 ifndef V