RIOT/Makefile.include: added compile time warning on conflicting features

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 ''

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

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."

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

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`

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;
+}

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")