Subject: [PATCH v3 0/3] Enable more compiler warnings for devs

From: Nguyễn Thái Ngọc Duy <[email-masked]>
Date: Thu, 29 Mar 2018 17:03:19 +0200

v3 fixes the fallthru warnings in connect.c, and with json-writer
series rerolled, 'pu' should build cleanly now.
-Wno-maybe-uninitialized is removed, thanks to Ramsay.

v3 also adds an experimental patch that adds EAGER_DEVELOPER=1. These
developers will have all warnings enabled (nothing is suppressed) but
they are not fatal. They could go through them and perhaps clean up
the code base a bit more.

Interdiff

diff --git a/Makefile b/Makefile
index e6680a8977..e4f04ce1cb 100644
--- a/Makefile
+++ b/Makefile
@@ -434,7 +434,9 @@ all::
 #
 # 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)
+# COMPILER_FEATURES (see config.mak.dev).
+# Define EAGER_DEVELOPER keeps compiler warnings non-fatal, but no warning
+# class is suppressed anymore.
 
 GIT-VERSION-FILE: FORCE
 	@$(SHELL_PATH) ./GIT-VERSION-GEN
@@ -1041,6 +1043,9 @@ include config.mak.uname
 -include config.mak.autogen
 -include config.mak
 
+ifdef EAGER_DEVELOPER
+DEVELOPER = Yes
+endif
 ifdef DEVELOPER
 include config.mak.dev
 endif
diff --git a/config.mak.dev b/config.mak.dev
index d8beaf9347..13883410b3 100644
--- a/config.mak.dev
+++ b/config.mak.dev
@@ -1,4 +1,6 @@
+ifndef EAGER_DEVELOPER
 CFLAGS += -Werror
+endif
 CFLAGS += -Wdeclaration-after-statement
 CFLAGS += -Wno-format-zero-length
 CFLAGS += -Wold-style-definition
@@ -18,13 +20,23 @@ endif
 
 ifneq ($(or $(filter gcc6,$(COMPILER_FEATURES)),$(filter clang4,$(COMPILER_FEATURES))),)
 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
+# These are disabled because we have these all over the place.
 CFLAGS += -Wno-empty-body
 CFLAGS += -Wno-missing-field-initializers
 CFLAGS += -Wno-sign-compare
 CFLAGS += -Wno-unused-function
 CFLAGS += -Wno-unused-parameter
-ifneq ($(filter gcc6,$(COMPILER_FEATURES)),)
-CFLAGS += -Wno-maybe-uninitialized
+endif
+endif
+
+# uninitialized warnings on gcc 4.9.2 in xdiff/xdiffi.c and config.c
+# not worth fixing since newer compilers correctly stop complaining
+ifneq ($(filter gcc4,$(COMPILER_FEATURES)),)
+ifeq ($(filter gcc5,$(COMPILER_FEATURES)),)
+CFLAGS += -Wno-uninitialized
 endif
 endif
diff --git a/connect.c b/connect.c
index c3a014c5ba..49eca46462 100644
--- a/connect.c
+++ b/connect.c
@@ -46,7 +46,7 @@ int check_ref_type(const struct ref *ref, int flags)
 	return check_ref(ref->name, flags);
 }
 
-static void die_initial_contact(int unexpected)
+static NORETURN void die_initial_contact(int unexpected)
 {
 	if (unexpected)
 		die(_("The remote end hung up upon initial contact"));

Nguyễn Thái Ngọc Duy (3):
  connect.c: mark die_initial_contact() NORETURN
  Makefile: detect compiler and enable more warnings in DEVELOPER=1
  Makefile: add EAGER_DEVELOPER mode

 Makefile        | 20 +++++++++----------
 config.mak.dev  | 42 +++++++++++++++++++++++++++++++++++++++
 connect.c       |  2 +-
 detect-compiler | 53 +++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 106 insertions(+), 11 deletions(-)
 create mode 100644 config.mak.dev
 create mode 100755 detect-compiler

-- 
2.17.0.rc1.439.gca064e2955