input: improve error message of layer version conflicts (#652)

Give the user more hints if a deeper layer requires a higher Bob version
than the project/layer(s) above.

Author: jkloetzke

.github/workflows/workflow.yaml

@@ -81,10 +81,6 @@ jobs:
                 distribution: 'temurin'
                 java-version: '21'
 
-            - name: Prepare MSYS2 environment
-              run: |
-                C:\msys64\usr\bin\bash -l -c "pacman -Sy --needed --noconfirm parallel || true"
-
             - name: Cache Jenkins integration test
               uses: actions/cache@v4
               with:

pym/bob/input.py

@@ -3938,8 +3938,12 @@ def __parseLayer(self, layerSpec, maxVer, recipesRoot, upperLayer):
         config = self.loadConfigYaml(self.loadYaml, rootDir)
         minVer = config.get("bobMinimumVersion", "0.16")
         if compareVersion(maxVer, minVer) < 0:
-            raise ParseError("Layer '{}' requires a higher Bob version than root project!"
-                                .format(layer))
+            if upperLayer:
+                upperLayer = f"layer '{upperLayer}'"
+            else:
+                upperLayer = "the root project"
+            raise ParseError(f"Layer '{layer}' requires a higher Bob version ({minVer}) than {upperLayer} ({maxVer})!",
+                             help=f"You need to adjust the bobMinimumVersion of {upperLayer} to be higher or equal to layer '{layer}'. Watch out for newly introduced policies between the two versions!")
         maxVer = minVer # sub-layers must not have a higher bobMinimumVersion
 
         # Determine policies. The root layer determines the default settings

test/run-tests.sh

@@ -274,14 +274,18 @@ fi
 # execute all tests, possibly in parallel
 if [[ ${#RUN_TEST_NAMES[@]} -eq 0 ]] ; then
 	: # No tests matched
-elif type -p parallel >/dev/null && [[ ${RUN_JOBS:-} != 1 ]] ; then
+elif [[ ${RUN_JOBS:-} != 1 ]] ; then
 	export -f run_test print_verbose
 	export RUN_PYTHON3
 	export RUN_PYTHON3_COV
 	export TEST_ENVIRONMENT
 	export VERBOSE
-	parallel --line-buffer ${RUN_JOBS:+-j $RUN_JOBS} run_test ::: \
-	  "${RUN_TEST_NAMES[@]}" || : $((FAILED+=$?))
+	# Run the tests in parallel and pipe them trough a dummy sed with line
+	# buffering.  This prevents the output from being interleaced.
+	echo "${RUN_TEST_NAMES[@]}" \
+		| xargs -P ${RUN_JOBS:-$(nproc)} -n 1 \
+			bash -c 'run_test "$@" | stdbuf -oL sed -e ""' bash \
+		|| : $((FAILED+=$?))
 else
 	for i in "${RUN_TEST_NAMES[@]}" ; do
 		if ! run_test "$i" ; then