Fix source context in split config

If a repo has multiple config files, we would previously share the
source context between all of those files.  However, one of the
attributes of a source context is the path from which the config
file was loaded, so debugging statements would show that all of the
config objects loaded from that repo came from the last filename
Zuul read.

Instead, make a copy of the source context for each path loaded.

Change-Id: Ib22da429b484a99c86c2e620d97f655710460df4

tests/fixtures/config/split-config/git/common-config/zuul.d/more-jobs.yaml

@@ -0,0 +1,3 @@
+- job:
+    name: project-test2
+    run: playbooks/project-test1.yaml

tests/unit/test_configloader.py

@@ -309,6 +309,22 @@ class TestSplitConfig(ZuulTestCase):
     def test_split_config(self):
         tenant = self.sched.abide.tenants.get('tenant-one')
         self.assertIn('project-test1', tenant.layout.jobs)
+        self.assertIn('project-test2', tenant.layout.jobs)
+        test1 = tenant.layout.getJob('project-test1')
+        self.assertEqual(test1.source_context.project.name, 'common-config')
+        self.assertEqual(test1.source_context.branch, 'master')
+        self.assertEqual(test1.source_context.path, 'zuul.d/jobs.yaml')
+        self.assertEqual(test1.source_context.trusted, True)
+        test2 = tenant.layout.getJob('project-test2')
+        self.assertEqual(test2.source_context.project.name, 'common-config')
+        self.assertEqual(test2.source_context.branch, 'master')
+        self.assertEqual(test2.source_context.path, 'zuul.d/more-jobs.yaml')
+        self.assertEqual(test2.source_context.trusted, True)
+
+        self.assertNotEqual(test1.source_context, test2.source_context)
+        self.assertTrue(test1.source_context.isSameProject(
+            test2.source_context))
+
         project_config = tenant.layout.project_configs.get(
             'review.example.com/org/project')
         self.assertIn('project-test1',

zuul/configloader.py

@@ -1526,7 +1526,8 @@ class TenantParser(object):
                             (job.source_context,))
                         continue
                     loaded = conf_root
-                    source_context = job.source_context
+                    # Create a new source_context so we have unique filenames.
+                    source_context = job.source_context.copy()
                     source_context.path = fn
                     self.log.info(
                         "Loading configuration from %s" %