web: remove SafeLoader left-over from ZuulJSONEncoder

When a job has a single key vars (or extra-vars/host-vars) that is named
after a zuul_node_types such as 'job', then the MappingProxy get
a SourceContext and ZuulMark attributes which can not be serialized.
The ZuulSafeLoader shouldn't add such node attributes in the first place,
but it doesn't seems possible to prevent that.

This change also removes the MappingProxyEncoder and replace it by the
existing ZuulJSONEncoder.

Change-Id: I9fe28a204d41944f86644117c16129234c9d3583

tests/fixtures/config/multi-tenant-semaphore/git/tenant-one-config/zuul.yaml

@@ -1,6 +1,9 @@
 - job:
     name: project1-test1
     semaphore: test-semaphore
+    vars:
+      semaphore:
+        test: 42
     run: playbooks/project1-test1.yaml
 
 - project:

zuul/lib/jsonutil.py

@@ -17,7 +17,11 @@ import types
 class ZuulJSONEncoder(json.JSONEncoder):
     def default(self, o):
         if isinstance(o, types.MappingProxyType):
-            return dict(o)
+            d = dict(o)
+            # Always remove SafeLoader left-over
+            d.pop('_source_context', None)
+            d.pop('_start_mark', None)
+            return d
         return json.JSONEncoder.default(self, o)
 
 

zuul/rpclistener.py

@@ -17,7 +17,6 @@ import json
 import logging
 import threading
 import traceback
-import types
 
 import gear
 
@@ -25,13 +24,7 @@ from zuul import model
 from zuul.connection import BaseConnection
 from zuul.lib import encryption
 from zuul.lib.config import get_default
-
-
-class MappingProxyEncoder(json.JSONEncoder):
-    def default(self, obj):
-        if isinstance(obj, types.MappingProxyType):
-            return dict(obj)
-        return json.JSONEncoder.default(self, obj)
+from zuul.lib.jsonutil import ZuulJSONEncoder
 
 
 class RPCListener(object):
@@ -361,7 +354,7 @@ class RPCListener(object):
         output = []
         for job in jobs:
             output.append(job.toDict(tenant))
-        gear_job.sendWorkComplete(json.dumps(output, cls=MappingProxyEncoder))
+        gear_job.sendWorkComplete(json.dumps(output, cls=ZuulJSONEncoder))
 
     def handle_job_list(self, job):
         args = json.loads(job.arguments)
@@ -431,7 +424,7 @@ class RPCListener(object):
                 config['pipelines'].append(pipeline)
             result['configs'].append(config)
 
-        gear_job.sendWorkComplete(json.dumps(result, cls=MappingProxyEncoder))
+        gear_job.sendWorkComplete(json.dumps(result, cls=ZuulJSONEncoder))
 
     def handle_project_list(self, job):
         args = json.loads(job.arguments)