diff --git a/Makefile.buildtests b/Makefile.buildtests
index 4a80aa47e1a95d1a1c06cd4e0483293d17ce48c7..d11d9da1d18d8524a1535c70154e34e317959242 100644
--- a/Makefile.buildtests
+++ b/Makefile.buildtests
@@ -164,6 +164,9 @@ info-build:
@echo 'FEATURES_MISSING (only non-optional features):'
@echo ' $(or $(sort $(filter-out $(FEATURES_OPTIONAL) $(FEATURES_PROVIDED), $(FEATURES_REQUIRED))), -none-)'
@echo ''
+ @echo 'FEATURES_CONFLICT: $(FEATURES_CONFLICT)'
+ @echo 'FEATURES_CONFLICT_MSG: $(FEATURES_CONFLICT_MSG)'
+ @echo ''
@echo 'CC: $(CC)'
@echo -e 'CFLAGS:$(patsubst %, \n\t%, $(CFLAGS))'
@echo ''
diff --git a/Makefile.include b/Makefile.include
index 8a543ba0a30dd64424771c0ebf496ca5d4c543d8..2177dadf1a1fe353aca0838d1a728b32be1c0674 100644
--- a/Makefile.include
+++ b/Makefile.include
@@ -37,6 +37,7 @@ ifeq (, ${JENKINS_URL})
ifeq (0, $(shell tput colors 2>&1 > /dev/null; echo $$?))
COLOR_GREEN := \033[1;32m
COLOR_RED := \033[1;31m
+ COLOR_YELLOW := \033[1;33m
COLOR_PURPLE := \033[1;35m
COLOR_RESET := \033[0m
ifeq ($(OS),Darwin)
@@ -316,6 +317,7 @@ include $(RIOTBASE)/Makefile.vars
# Warn if the selected board and drivers don't provide all needed featues:
ifneq (, $(filter all, $(if $(MAKECMDGOALS), $(MAKECMDGOALS), all)))
EXPECT_ERRORS :=
+ EXPECT_CONFLICT :=
# Test if there where dependencies against a module in DISABLE_MODULE.
ifneq (, $(filter $(DISABLE_MODULE), $(USEMODULE)))
@@ -331,6 +333,17 @@ ifneq (, $(filter all, $(if $(MAKECMDGOALS), $(MAKECMDGOALS), all)))
EXPECT_ERRORS := 1
endif
+ # Test if any required feature conflict with another one.
+ CONFLICT := $(foreach var,$(FEATURES_CONFLICT),$(if $(filter $(words $(subst :, ,$(var))),$(words $(filter $(FEATURES_REQUIRED),$(subst :, ,$(var))))),$(subst :, ,$(var))))
+ ifneq (, $(strip $(CONFLICT)))
+ $(shell $(COLOR_ECHO) "$(COLOR_YELLOW)The following features may conflict:$(COLOR_RESET)"\
+ "$(COLOR_GREEN)$(sort $(filter $(FEATURES_REQUIRED), $(CONFLICT)))$(COLOR_RESET)" 1>&2)
+ ifneq (, $(FEATURES_CONFLICT_MSG))
+ $(shell $(COLOR_ECHO) "$(COLOR_YELLOW)Rationale: $(COLOR_RESET)$(FEATURES_CONFLICT_MSG)" 1>&2)
+ endif
+ EXPECT_CONFLICT := 1
+ endif
+
# If there is a whitelist, then test if the board is whitelisted.
ifneq (, $(BOARD_WHITELIST))
ifeq (, $(filter $(BOARD_WHITELIST), $(BOARD)))
@@ -347,9 +360,14 @@ ifneq (, $(filter all, $(if $(MAKECMDGOALS), $(MAKECMDGOALS), all)))
endif
endif
+ ifneq (, $(EXPECT_CONFLICT))
+ $(shell $(COLOR_ECHO) "\n$(COLOR_YELLOW)EXPECT undesired behaviour!$(COLOR_RESET)" 1>&2)
+ endif
+
ifneq (, $(EXPECT_ERRORS))
$(shell $(COLOR_ECHO) "\n\n$(COLOR_RED)EXPECT ERRORS!$(COLOR_RESET)\n\n" 1>&2)
endif
+
endif
else # RIOT_VERSION
diff --git a/boards/stm32f4discovery/Makefile.features b/boards/stm32f4discovery/Makefile.features
index bf0edc3fb0fe96db197b8646d7e5a003a798d8c3..f17556808cc5a09b9cf422640cdcee4416f25e27 100644
--- a/boards/stm32f4discovery/Makefile.features
+++ b/boards/stm32f4discovery/Makefile.features
@@ -9,3 +9,7 @@ FEATURES_PROVIDED += periph_adc
FEATURES_PROVIDED += periph_dac
FEATURES_PROVIDED += periph_cpuid
FEATURES_MCU_GROUP = cortex_m4
+
+FEATURES_CONFLICT += periph_spi:periph_dac
+
+FEATURES_CONFLICT_MSG += "On stm32f4discovery boards there are the same pins for the DAC and/or SPI_0."
diff --git a/tests/warn_conflict/Makefile b/tests/warn_conflict/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..e3c6cd2750c2c2b50a608159b182c411966df47f
--- /dev/null
+++ b/tests/warn_conflict/Makefile
@@ -0,0 +1,12 @@
+APPLICATION = warn_conflict
+include ../Makefile.tests_common
+
+# The stm32f4discovery is the only board that provides known conflicting features,
+# so using this compile test on other boards will not provide the expected warning.
+BOARD_WHITELIST := stm32f4discovery
+
+# These features have a chance to use/access the shared `SPI_0` on stm32f4discovery,
+# which would probably produce an unexpected behaviour in the user application.
+FEATURES_REQUIRED = periph_dac periph_spi
+
+include $(RIOTBASE)/Makefile.include
diff --git a/tests/warn_conflict/README.md b/tests/warn_conflict/README.md
new file mode 100644
index 0000000000000000000000000000000000000000..0169964a842272fdad67ea1ed8c2ca0c0a9cc373
--- /dev/null
+++ b/tests/warn_conflict/README.md
@@ -0,0 +1,41 @@
+Test warning on conflicting features
+==================================================
+Using conflicting features provided by boards was invisible for the user until the used features resulted in a traceable problem or the user was aware of the conflict in advance from documentation ect.
+Now, existing and known conflicts can be recorded into `FEATURES_CONFLICT` for each board to inform the user on a conflict situation during compile time.
+
+This test requires conflicting features in its `Makefile`, i.e. `FEATURES_REQUIRED = periph_dac periph_spi`.
+It is expected to be presented with a warning on the conflicts with a short description message during compile time for the [stm32f4discovery](https://github.com/RIOT-OS/RIOT/wiki/Board%3A-STM32F4discovery) by now, i.e. :
+
+```
+$ make BOARD=stm32f4discovery
+The following features may conflict: periph_dac periph_spi
+Rationale: On stm32f4discovery boards there are the same pins for the DAC and/or SPI_0.
+
+EXPECT undesired behaviour!
+```
+The warning presents the conflicting features derived from `FEATURES_CONFLICT` and an optional message derived from `FEATURES_CONFLICT_MSG` provided int the `./RIOT/board/stm32f4discovery/Makefile.features`.
+
+Whenever an application, such as this test, requires board features that match a _conflict group_, e.g. `FEATURES_REQUIRED = periph_dac periph_spi`, a similar warning to the above will be displayed during compile time.
+
+
+---------
+###Usage of _conflict groups_:
+
+* Conflicting features are described in groups separated by a `:` (doublecolon) for each feature, e.g.:
+`FEATURES_CONFLICT = periph_spi:periph_dac`, which states that `periph_spi` conflicts with `periph_dac`.
+As seen above, this is the conflict of `SPI_0` pinout is shared with `DAC` on the [stm32f4discovery](https://github.com/RIOT-OS/RIOT/wiki/Board%3A-STM32F4discovery) board.
+
+* Distinct groups of conflicts are whitespace separated, e.g.:
+`featureA:featureB featureC:featureD`, which states that `featureA` conflicts with `featureB`, and `featureC` conflicts with `featureD`.
+This also means, that e.g. `FEATURES_REQUIRED = featureA featureD` would **not** produce a warning.
+
+* The groups can have an arbitrary number of conflicting features, e.g.:
+`featureA:featureB:featureC:featureX:featureY:featureZ`
+
+* An optional information can be given using the `FEATURES_CONFLICT_MSG`, e.g.:
+`FEATURES_CONFLICT_MSG = "featureA uses the same pins as featureB"`
+
+* If the required features match multiple conflict groups, **ALL** conflicting features are provided to the user, e.g.:
+`FEATURES_CONFLICT = featureA:featureB featureC:featureD` and
+`FEATURES_REQUIRED = featureA featureB featureC featureD`
+would result in: `The following features may conflict: featureA featureB featureC featureD`
diff --git a/tests/warn_conflict/main.c b/tests/warn_conflict/main.c
new file mode 100644
index 0000000000000000000000000000000000000000..6e5230d6b13ed2ebab52c3fb5bbea9a3064ca12f
--- /dev/null
+++ b/tests/warn_conflict/main.c
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2014 Martin Landsmann <Martin.Landsmann@HAW-Hamburg.de>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @ingroup tests
+ * @{
+ *
+ * @file
+ * @brief Test whether EXPECT_CONFLICT works.
+ *
+ * @author Martin Landsmann <Martin.Landsmann@HAW-Hamburg.de>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+
+int main(void)
+{
+ puts("Hello, nothing to do here.\nbye.");
+
+ return 0;
+}
diff --git a/tests/warn_conflict/test.py b/tests/warn_conflict/test.py
new file mode 100755
index 0000000000000000000000000000000000000000..65a2b2568d6e999cbaea7edb9bd030c6a67f4973
--- /dev/null
+++ b/tests/warn_conflict/test.py
@@ -0,0 +1,22 @@
+#!/usr/bin/env python3
+import subprocess, os
+
+cross_gcc = "arm-none-eabi-gcc"
+
+try:
+ devnull = open(os.devnull)
+ subprocess.Popen([cross_gcc], stdout=devnull, stderr=devnull).communicate()
+ output = subprocess.Popen(["make", "BOARD=stm32f4discovery"], stderr=subprocess.PIPE, stdout=subprocess.PIPE )
+ out,err = output.communicate()
+
+ compare = b'\x1b[1;33mThe following features may conflict:\x1b[0m \x1b[1;32mperiph_dac periph_spi\x1b[0m\n\x1b[1;33mRationale: \x1b[0mOn stm32f4discovery boards there are the same pins for the DAC and/or SPI_0.\n\n\x1b[1;33mEXPECT undesired behaviour!\x1b[0m\n'
+ if err == compare:
+ print("Test SUCCEEDED! Compile time output is as expected!\n")
+ else:
+ print("Test FAILED! Compile time output is NOT as expected!\n")
+ print("Expected:\n" + compare.decode("ascii") )
+ print("Received:\n" + err.decode("ascii") )
+
+except OSError as e:
+ if e.errno == os.errno.ENOENT:
+ print("ABORTING TEST:"+ cross_gcc +" seems to be missing.\n")