Exceptions in resolver are caught (no traceback)

[ceelian]

Version:
GraphQL-core-next 1.0.1
Python 3.7.1

Current Behaviour:

Exceptions in resolvers are caught by default and the traceback of the original_error doesn't help debugging.

Traceback output of log.exception('', exc_info=result.errors[0].original_error)

Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/graphql/execution/execute.py", line 664, in complete_value_catching_error
    return_type, field_nodes, info, path, result
  File "/usr/local/lib/python3.6/site-packages/graphql/execution/execute.py", line 731, in complete_value
    raise result
graphql.error.graphql_error.GraphQLError: My exception

Expected Behaviour:

1. There is a flag raise_exception which switches if exceptions are caught or if they are raised out of the library resolver.

2. The traceback of the original_errors is meaningful: leads to the source line where the exception occurred.

[Cito]

@ceelian - thanks for the feedback. Changeset e0bb443 should improve this.

Here is an example how you can get error tracebacks now:

from traceback import print_tb
from graphql import *

def bad_resolver(obj, info):
    raise RuntimeError("the runtime error")

schema = GraphQLSchema(query=GraphQLObjectType(
    name='RootQueryType',
    fields={'bad': GraphQLField(GraphQLString, resolve=bad_resolver)}))

error = graphql_sync(schema, '{ bad }').errors[0]
original_error = error.original_error

print(error)
print_tb(error.__traceback__)

Output:

the runtime error

GraphQL request (1:3)
1: { bad }
     ^

  File ".../execute.py", line 664, in complete_value_catching_error
    return_type, field_nodes, info, path, result
  File ".../execute.py", line 731, in complete_value
    raise result
  File "../execute.py", line 619, in resolve_field_value_or_error
    result = resolve_fn(source, info, **args)
  File "test_graphql.py", line 7, in bad_resolver
    raise RuntimeError("the runtime error")

Will release an upate with this improvement soon.

[ceelian]

Great, thank you for the improvement!

[ezyang]

Thank you, I was affected by this too.

[Cito]

Version 1.0,2 with this fix has now been released on PyPI.