Handle issue metadata properly (google#4174)

Since it's a heterogenous dictionary, we must store it as a string
representation of a json dict (as unwieldy as this is, it's the only
correct way to do this).

Fixes:
https://pantheon.corp.google.com/errors/detail/CODtycKwtN-pGA;filter=%5B%22Type%22%5D;time=P30D;locations=global?e=-13802955&invt=AbZgCw&mods=logs_tg_prod&project=google.com:cluster-fuzz

```
Bar chart

Sample stack trace
Parsed
Raw
TypeError: bad argument type for built-in operation

at .update ( <frozen _collections_abc>:949 )
at .find_fixed_range ( /mnt/scratch0/clusterfuzz/src/clusterfuzz/_internal/bot/tasks/utasks/progression_task.py:567 )
at .utask_main ( /mnt/scratch0/clusterfuzz/src/clusterfuzz/_internal/bot/tasks/utasks/progression_task.py:671 )
at .uworker_main_no_io ( /mnt/scratch0/clusterfuzz/src/clusterfuzz/_internal/bot/tasks/utasks/__init__.py:211 )
at .execute_locally ( /mnt/scratch0/clusterfuzz/src/clusterfuzz/_internal/bot/tasks/task_types.py:63 )
at .execute ( /mnt/scratch0/clusterfuzz/src/clusterfuzz/_internal/bot/tasks/task_types.py:127 )
at .run_command ( /mnt/scratch0/clusterfuzz/src/clusterfuzz/_internal/bot/tasks/commands.py:218 )
at .process_command_impl ( /mnt/scratch0/clusterfuzz/src/clusterfuzz/_internal/bot/tasks/commands.py:429 )
at .wrapper ( /mnt/scratch0/clusterfuzz/src/clusterfuzz/_internal/bot/tasks/commands.py:159 )
at .process_command ( /mnt/scratch0/clusterfuzz/src/clusterfuzz/_internal/bot/tasks/commands.py:248 )
at .task_loop ( /mnt/scratch0/clusterfuzz/src/python/bot/startup/run_bot.py:146 )
```

src/clusterfuzz/_internal/bot/tasks/utasks/analyze_task.py

@@ -14,6 +14,8 @@
 """Analyze task for handling user uploads."""
 
 import datetime
+import json
+from typing import Dict
 from typing import Optional
 
 from clusterfuzz._internal.base import tasks
@@ -36,7 +38,8 @@
 from clusterfuzz._internal.system import environment
 
 
-def _add_default_issue_metadata(testcase, fuzz_target_metadata):
+def _add_default_issue_metadata(testcase: data_types.Testcase,
+                                fuzz_target_metadata: Dict):
   """Adds the default issue metadata (e.g. components, labels) to testcase."""
   testcase_metadata = testcase.get_metadata()
   for key, default_value in fuzz_target_metadata.items():
@@ -420,7 +423,7 @@ def utask_main(uworker_input):
       analyze_task_output=analyze_task_output,
       test_timeout=test_timeout,
       crash_time=crash_time,
-      issue_metadata=fuzz_target_metadata)
+      issue_metadata=json.dumps(fuzz_target_metadata))
 
 
 def test_for_reproducibility(fuzz_target, testcase, testcase_file_path, state,
@@ -565,7 +568,7 @@ def utask_postprocess(output):
   testcase_upload_metadata.security_flag = testcase.security_flag
   testcase_upload_metadata.put()
 
-  _add_default_issue_metadata(testcase, output.issue_metadata)
+  _add_default_issue_metadata(testcase, json.loads(output.issue_metadata))
   logs.info('Creating post-analyze tasks.')
 
   # Create tasks to

src/clusterfuzz/_internal/bot/tasks/utasks/corpus_pruning_task.py

@@ -15,6 +15,7 @@
 
 import collections
 import datetime
+import json
 import os
 import random
 import shutil
@@ -842,7 +843,7 @@ def _process_corpus_crashes(output: uworker_msg_pb2.Output):  # pylint: disable=
                             corpus_pruning_output.fuzzer_binary_name)
 
       if output.issue_metadata:
-        for key, value in output.issue_metadata.items():
+        for key, value in json.loads(output.issue_metadata).items():
           testcase.set_metadata(key, value, update_testcase=False)
 
         testcase.put()
@@ -1032,7 +1033,7 @@ def utask_main(uworker_input):
             crash_revision=result.revision,
             crashes=_extract_corpus_crashes(result),
             corpus_backup_uploaded=bool(result.coverage_info.corpus_location)),
-        issue_metadata=issue_metadata)
+        issue_metadata=json.dumps(issue_metadata))
     _fill_cross_pollination_stats(result.cross_pollination_stats,
                                   uworker_output)
   except Exception as e:

src/clusterfuzz/_internal/bot/tasks/utasks/progression_task.py

@@ -13,7 +13,9 @@
 # limitations under the License.
 """Test to see if test cases are fixed."""
 
+import json
 import time
+from typing import Dict
 from typing import List
 
 from clusterfuzz._internal.base import bisection
@@ -297,15 +299,15 @@ def _check_fixed_for_custom_binary(testcase: data_types.Testcase,
   return uworker_msg_pb2.Output(progression_task_output=progression_task_output)  # pylint: disable=no-member
 
 
-def _update_issue_metadata(testcase, metadata):
+def _update_issue_metadata(testcase: data_types.Testcase, metadata: Dict):
   if not metadata:
     return
 
   for key, value in metadata.items():
     old_value = testcase.get_metadata(key)
     if old_value != value:
-      logs.info('Updating issue metadata for {} from {} to {}.'.format(
-          key, old_value, value))
+      logs.info(
+          f'Updating issue metadata for {key} from {old_value} to {value}.')
       testcase.set_metadata(key, value)
 
 
@@ -570,7 +572,7 @@ def find_fixed_range(uworker_input):
         last_tested_crash_stacktrace)
     return uworker_msg_pb2.Output(
         progression_task_output=progression_task_output,
-        issue_metadata=issue_metadata)
+        issue_metadata=json.dumps(issue_metadata))
 
   # Verify that we do crash in the min revision. This is assumed to be true
   # while we are doing the bisect.
@@ -585,7 +587,7 @@ def find_fixed_range(uworker_input):
     progression_task_output.crash_revision = int(min_revision)
     return uworker_msg_pb2.Output(  # pylint: disable=no-member
         progression_task_output=progression_task_output,
-        issue_metadata=issue_metadata,
+        issue_metadata=json.dumps(issue_metadata),
         error_message=error_message,
         error_type=uworker_msg_pb2.ErrorType.PROGRESSION_NO_CRASH)  # pylint: disable=no-member
 
@@ -607,7 +609,7 @@ def find_fixed_range(uworker_input):
       progression_task_output.max_revision = int(max_revision)
       return uworker_msg_pb2.Output(  # pylint: disable=no-member
           progression_task_output=progression_task_output,
-          issue_metadata=issue_metadata)
+          issue_metadata=json.dumps(issue_metadata))
 
     # Occasionally, we get into this bad state. It seems to be related to test
     # cases with flaky stacks, but the exact cause is unknown.
@@ -622,7 +624,7 @@ def find_fixed_range(uworker_input):
         progression_task_output.last_progression_max = int(last_progression_max)
       return uworker_msg_pb2.Output(  # pylint: disable=no-member
           progression_task_output=progression_task_output,
-          issue_metadata=issue_metadata,
+          issue_metadata=json.dumps(issue_metadata),
           error_type=uworker_msg_pb2.ErrorType.PROGRESSION_BAD_STATE_MIN_MAX)  # pylint: disable=no-member
 
     # Test the middle revision of our range.
@@ -662,7 +664,7 @@ def find_fixed_range(uworker_input):
     progression_task_output.last_progression_max = last_progression_max
   return uworker_msg_pb2.Output(  # pylint: disable=no-member
       error_message=error_message,
-      issue_metadata=issue_metadata,
+      issue_metadata=json.dumps(issue_metadata),
       progression_task_output=progression_task_output,
       error_type=uworker_msg_pb2.ErrorType.PROGRESSION_TIMEOUT)  # pylint: disable=no-member
 
@@ -705,7 +707,7 @@ def utask_postprocess(output: uworker_msg_pb2.Output):  # pylint: disable=no-mem
   task_output = None
 
   if output.issue_metadata:
-    _update_issue_metadata(testcase, output.issue_metadata)
+    _update_issue_metadata(testcase, json.loads(output.issue_metadata))
 
   if output.HasField('progression_task_output'):
     task_output = output.progression_task_output

src/clusterfuzz/_internal/protos/uworker_msg.proto

@@ -395,6 +395,6 @@ message Output {
   optional SymbolizeTaskOutput symbolize_task_output = 13;
   optional VariantTaskOutput variant_task_output = 14;
   optional CorpusPruningTaskOutput corpus_pruning_task_output = 16;
-  map<string,string> issue_metadata = 17;
+  optional string issue_metadata = 20;
   optional string error_message = 15;
 }

src/clusterfuzz/_internal/tests/core/bot/tasks/utasks/uworker_io_test.py

@@ -14,6 +14,7 @@
 """Tests for uworker_io."""
 
 import datetime
+import json
 import os
 import tempfile
 import unittest
@@ -347,15 +348,6 @@ def test_list_update(self):
     deserialized = uworker_io.deserialize_uworker_input(wire_format)
     self.assertEqual(deserialized.analyze_task_input.bad_revisions, [0, 1])
 
-  def test_map_update(self):
-    """Tests that updating a map works."""
-    output = uworker_msg_pb2.Output(issue_metadata={'a': 'b', 'c': 'd'})
-    output.issue_metadata.clear()
-    output.issue_metadata.update({'e': 'f'})
-    wire_format = uworker_io.serialize_uworker_output(output)
-    deserialized = uworker_io.deserialize_uworker_output(wire_format)
-    self.assertEqual(deserialized.issue_metadata, {'e': 'f'})
-
   def test_submessage_references(self):
     """Tests that updating a submessage works both when directly reading from
     uworker_input and from reading from it once it has been serialized and
@@ -381,3 +373,17 @@ def test_unset_a_message_field(self):
     wire_format = uworker_io.serialize_uworker_input(uworker_input)
     deserialized = uworker_io.deserialize_uworker_input(wire_format)
     self.assertFalse(deserialized.HasField('analyze_task_input'))
+
+  def test_issue_metadata_field(self):
+    """Tests issue_metadata a serialized json string."""
+    metadata = {
+        'sam': 1,
+        'i': 2.1,
+        'am': {
+            'rhyme': [89]
+        },
+    }
+    output = uworker_msg_pb2.Output(issue_metadata=json.dumps(metadata))
+    wire_format = uworker_io.serialize_uworker_input(output)
+    deserialized = uworker_io.deserialize_uworker_output(wire_format)
+    self.assertEqual(json.loads(deserialized.issue_metadata), metadata)