Keep track of defconfig that's in use

This is useful for making sure that the right environment is in use.

Author: fhunleth

.gitignore

@@ -2,3 +2,4 @@ buildroot
 .buildroot-downloaded
 .buildroot-patched
 *~
+.nerves-defconfig

Makefile

@@ -43,6 +43,7 @@ reset-buildroot: .buildroot-downloaded
 update-patches: reset-buildroot .buildroot-patched
 
 %_defconfig: $(TOPDIR)/configs/%_defconfig .buildroot-patched
+	echo "$@" > .nerves-defconfig
 	$(MAKE_BR) $@
 
 buildroot/.config: .buildroot-patched
@@ -76,8 +77,8 @@ menuconfig: buildroot/.config
 	$(MAKE_BR) savedefconfig
 	@echo
 	@echo "!!! Important !!!"
-	@echo "1. Remember to copy buildroot/defconfig to the configs directory to save"
-	@echo "   the new settings."
+	@echo "1. Remember to copy buildroot/defconfig to configs/$(shell cat .nerves-defconfig)"
+	@echo "   or another file in the configs directory to save the new settings."
 	@echo "2. Buildroot normally requires you to run 'make clean' and 'make' after"
 	@echo "   changing the configuration. You don't technically have to do this,"
 	@echo "   but if you're new to Buildroot, it's best to be safe."
@@ -102,7 +103,7 @@ busybox-menuconfig: buildroot/.config
 clean: realclean
 distclean: realclean
 realclean:
-	-rm -fr buildroot .buildroot-patched .buildroot-downloaded
+	-rm -fr buildroot .buildroot-patched .buildroot-downloaded .nerves-defconfig
 
 help:
 	@echo 'Nerves SDK Help'

nerves-env.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 
 # Source this script to setup your environment to cross-compile
-# and build Erlang apps for this nerves-sdk build.
+# and build Erlang apps for this Nerves build.
 
 if [ "$SHELL" != "/bin/bash" ]; then
     echo ERROR: This script currently only works from bash.
@@ -12,13 +12,31 @@ if [ "$0" != "bash" -a "$0" != "-bash" -a "$0" != "/bin/bash" ]; then
     echo ERROR: This scripted should be sourced from bash:
     echo
     echo source $BASH_SOURCE
+    echo
     return 1
     exit 1
 fi
 
 NERVES_ROOT=$(dirname $(readlink -f $BASH_SOURCE))
+NERVES_DEFCONFIG=`cat $NERVES_ROOT/.nerves-defconfig`
 
 source $NERVES_ROOT/scripts/nerves-env-helper.sh $NERVES_ROOT
 
-echo Shell environment updated for nerves
-echo Cross-compiler prefix: `basename $CROSSCOMPILE`
+echo "Shell environment updated for Nerves"
+echo
+echo "Nerves configuration: $NERVES_DEFCONFIG"
+echo "Cross-compiler prefix: `basename $CROSSCOMPILE`"
+if ! diff $NERVES_ROOT/configs/$NERVES_DEFCONFIG $NERVES_ROOT/buildroot/defconfig >/dev/null; then
+    echo
+    echo "----------------------------------------------------------------------------"
+    echo "Your Nerves configuation (configs/$NERVES_DEFCONFIG) does not match"
+    echo "$NERVES_ROOT/buildroot/defconfig!"
+    echo "This means that you may have unsaved changes. This is ok if you're"
+    echo "experimenting with Buildroot, but be sure to save or revert your changes"
+    echo "when you are done."
+    echo
+    echo "Changes:"
+    diff $NERVES_ROOT/configs/$NERVES_DEFCONFIG $NERVES_ROOT/buildroot/defconfig
+    echo "----------------------------------------------------------------------------"
+    echo
+fi