yocto-compat-layer: better handling of per-machine world build breakage

It is fairly common that BSP layers enable recipes when choosing
machines from that layer without checking whether the recipe actually
builds in the current distro. That breaks "bitbake world", retrieving
signatures and thus the test_machine_signatures test.

It's better to let that test continue with the signatures that can be
retrieved and report the broken world build separately. Right now, the
new test_machine_world iterates over all machines. More elegant and
useful in combination with a (currently missing) selection of which
tests to run would be to generate one test instance per machine. But that
is not straightforward and has to wait.

The "-k" argument alone was not enough to proceed despite failures,
because bitbake then still returns a non-zero exit code. The existance
of the output file is taken as sign that the bitbake execution managed
was not fatally broken.

(From OE-Core rev: 02f5d7836b726e40fef82b50b8145acc839b360b)

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/lib/compatlayer/__init__.py

@@ -233,9 +233,21 @@ def get_signatures(builddir, failsafe=False, machine=None):
     if failsafe:
         cmd += '-k '
     cmd += '-S none world'
-    check_command('Generating signatures failed. This might be due to some parse error and/or general layer incompatibilities.',
-                  cmd)
     sigs_file = os.path.join(builddir, 'locked-sigs.inc')
+    if os.path.exists(sigs_file):
+        os.unlink(sigs_file)
+    try:
+        check_command('Generating signatures failed. This might be due to some parse error and/or general layer incompatibilities.',
+                      cmd)
+    except RuntimeError as ex:
+        if failsafe and os.path.exists(sigs_file):
+            # Ignore the error here. Most likely some recipes active
+            # in a world build lack some dependencies. There is a
+            # separate test_machine_world_build which exposes the
+            # failure.
+            pass
+        else:
+            raise
 
     sig_regex = re.compile("^(?P<task>.*:.*):(?P<hash>.*) .$")
     tune_regex = re.compile("(^|\s)SIGGEN_LOCKEDSIGS_t-(?P<tune>\S*)\s*=\s*")

scripts/lib/compatlayer/cases/bsp.py

@@ -25,6 +25,32 @@ class BSPCompatLayer(OECompatLayerTestCase):
                 msg="Layer %s modified machine %s -> %s" % \
                     (self.tc.layer['name'], self.td['bbvars']['MACHINE'], machine))
 
+
+    def test_machine_world(self):
+        '''
+        "bitbake world" is expected to work regardless which machine is selected.
+        BSP layers sometimes break that by enabling a recipe for a certain machine
+        without checking whether that recipe actually can be built in the current
+        distro configuration (for example, OpenGL might not enabled).
+
+        This test iterates over all machines. It would be nicer to instantiate
+        it once per machine. It merely checks for errors during parse
+        time. It does not actually attempt to build anything.
+        '''
+
+        if not self.td['machines']:
+            self.skipTest('No machines set with --machines.')
+        msg = []
+        for machine in self.td['machines']:
+            # In contrast to test_machine_signatures() below, errors are fatal here.
+            try:
+                get_signatures(self.td['builddir'], failsafe=False, machine=machine)
+            except RuntimeError as ex:
+                msg.append(str(ex))
+        if msg:
+            msg.insert(0, 'The following machines broke a world build:')
+            self.fail('\n'.join(msg))
+
     def test_machine_signatures(self):
         '''
         Selecting a machine may only affect the signature of tasks that are specific