Subject: [PATCH 4/3] Makefile: untangle DEVELOPER and -Werror

From: Ævar Arnfjörð Bjarmason <[email-masked]>
Date: Sat, 31 Mar 2018 16:40:09 +0000

Change the DEVELOPER flag, and the newly added EAGER_DEVELOPER flag
which (approximately) enables -Wextra so that any combination of them
and -Werror can be set.

I've long wanted to use DEVELOPER=1 in my production builds, but on
some old systems I still get warnings, and thus the build would
fail. However if the build/tests fail for some other reason, it would
still be useful to scroll up and see what the relevant code is warning
about.

This change allows for that. Now setting DEVELOPER will set -Werror as
before, but if DEVELOPER_NONFATAL is set you'll get the same warnings,
but without -Werror.

I've renamed the newly added EAGER_DEVELOPER flag to
DEVELOPER_EXTRA. The reason is that it approximately turns on -Wextra,
and it'll be more consistent to add e.g. DEVELOPER_PEDANTIC later than
inventing some new name of our own (VERY_EAGER_DEVELOPER?).

The DEVELOPER_EXTRA flag implicitly means DEVELOPER_NONFATAL, but just
so that this change doesn't introduce yet another arbitrary limitation
it's possible to combine it with DEVELOPER_FATAL, which will turn on
-Werror for it as well.

Signed-off-by: Ævar Arnfjörð Bjarmason <[email-masked]>
---

I really like where this is going, but as noted I think this on top
would be even better.

 Makefile       | 17 +++++++++++------
 config.mak.dev | 10 ++++++++--
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/Makefile b/Makefile
index e4f04ce1cb..641461a569 100644
--- a/Makefile
+++ b/Makefile
@@ -432,11 +432,16 @@ all::
 # When cross-compiling, define HOST_CPU as the canonical name of the CPU on
 # which the built Git will run (for instance "x86_64").
 #
-# Define DEVELOPER to enable more compiler warnings. Compiler version
-# and faimily are auto detected, but could be overridden by defining
-# COMPILER_FEATURES (see config.mak.dev).
-# Define EAGER_DEVELOPER keeps compiler warnings non-fatal, but no warning
-# class is suppressed anymore.
+# Define DEVELOPER to enable more compiler warnings. We'll also enable
+# -Werror unless DEVELOPER_NONFATAL is defined. To enable even more
+# pedantic warnings that'll flag some potential existing issues in the
+# codebase turn on DEVELOPER_EXTRA, which implicitly sets DEVELOPER as
+# well, This is -Wextra with a whitelist of disabled warnings. Unless
+# DEVELOPER_NONFATAL is set DEVELOPER_EXTRA will turn it on
+# implicitly, so if you for some reason want both DEVELOPER and
+# DEVELOPER_EXTRA with fatal warnings, you need to set
+# DEVELOPER_FATAL=1 to force -Werror. See config.mak.dev for how this
+# all works.
 
 GIT-VERSION-FILE: FORCE
 	@$(SHELL_PATH) ./GIT-VERSION-GEN
@@ -1043,7 +1048,7 @@ include config.mak.uname
 -include config.mak.autogen
 -include config.mak
 
-ifdef EAGER_DEVELOPER
+ifdef DEVELOPER_EXTRA
 DEVELOPER = Yes
 endif
 ifdef DEVELOPER
diff --git a/config.mak.dev b/config.mak.dev
index 13883410b3..40f3365729 100644
--- a/config.mak.dev
+++ b/config.mak.dev
@@ -1,6 +1,12 @@
-ifndef EAGER_DEVELOPER
+ifndef DEVELOPER_NONFATAL
+ifndef DEVELOPER_EXTRA
 CFLAGS += -Werror
 endif
+endif
+ifdef DEVELOPER_FATAL
+CFLAGS += -Werror
+endif
+
 CFLAGS += -Wdeclaration-after-statement
 CFLAGS += -Wno-format-zero-length
 CFLAGS += -Wold-style-definition
@@ -23,7 +29,7 @@ CFLAGS += -Wextra
 # if a function is public, there should be a prototype and the right
 # header file should be included. If not, it should be static.
 CFLAGS += -Wmissing-prototypes
-ifndef EAGER_DEVELOPER
+ifndef DEVELOPER_EXTRA
 # These are disabled because we have these all over the place.
 CFLAGS += -Wno-empty-body
 CFLAGS += -Wno-missing-field-initializers
-- 
2.17.0.rc1.321.gba9d0f2565