Bug 1298328 - Fix dependency between buildid.h and libxul, do not re-generate buildid.h for every developer build. r=ted

For automation builds, force buildid.h to be regenerated, and always
#include buildid.h in nsAppRunner.cpp. This will eliminate the mismatch at the
cost of re-linking libxul on every build.

For developer builds, always #include buildid.h in nsAppRunner.cpp, but do not
force buildid.h to be re-generated for incremental builds. This means we will
never have a mismatch between platform and application buildids, although
subsequent builds are no longer guaranteed to have a new buildid.

MozReview-Commit-ID: 19hvu8AQXgN

--HG--
extra : rebase_source : 181b53c2cc47526bd632a0931ba6e65fc74179ef

Makefile.in

@@ -31,8 +31,13 @@ DIST_GARBAGE = config.cache config.log config.status* config-defs.h \
    .mozconfig.mk
 
 ifndef MOZ_PROFILE_USE
+# Automation builds should always have a new buildid, but for the sake of not
+# re-linking libxul on every incremental build we do not enforce this for
+# developer builds.
+ifneq (,$(MOZ_AUTOMATION)$(MOZ_BUILD_DATE))
 buildid.h source-repo.h: FORCE
 endif
+endif
 
 ifdef JS_STANDALONE
 configure_dir = $(topsrcdir)/js/src

toolkit/xre/Makefile.in

@@ -1,21 +0,0 @@
-# -*- makefile -*-
-# vim:set ts=8 sw=8 sts=8 noet:
-
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-milestone_txt = $(topsrcdir)/config/milestone.txt
-
-include $(topsrcdir)/config/rules.mk
-
-MOZ_BUILDID   := $(shell awk '{print $$3}' $(DEPTH)/buildid.h)
-$(call errorIfEmpty,GRE_MILESTONE MOZ_BUILDID)
-
-MK_COMPILE_DEFINES = -DMOZ_BUILDID=$(MOZ_BUILDID)
-
-# Note these dependencies are broken because the target is *not* the cpp file.
-# BUT, actually fixing it would make libxul rebuilt on every single incremental
-# build because of the automatic buildid change. This is why we can't actually
-# include buildid.h there, because it would add the dependency.
-$(srcdir)/nsAppRunner.cpp: $(DEPTH)/buildid.h $(milestone_txt)

toolkit/xre/nsAppRunner.cpp

@@ -271,12 +271,7 @@ nsString gAbsoluteArgv0Path;
 #include <fontconfig/fontconfig.h>
 #endif
 #include "BinaryPath.h"
-#ifndef MOZ_BUILDID
-// See comment in Makefile.in why we want to avoid including buildid.h.
-// Still include it when MOZ_BUILDID is not set, which can happen with some
-// build backends.
 #include "buildid.h"
-#endif
 
 #ifdef MOZ_LINKER
 extern "C" MFBT_API bool IsSignalHandlingBroken();