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Validation/coercion of input variables violates the GraphQL spec

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#223 1 comment 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Stale
Tech stack
graphql, python

Research direction

The issue points to coerce_variable_values in src/graphql/execution/values.py and graphql-core's execute() entry point. Read that function and its callers first; done means invalid variable_values cause GraphQLError to be raised as a request error, with no data entry in the response.

Written by the indexing model from the issue text.

Description

When callling graphql-core's execute() function with variable_values which do not pass validation -- for example, including an unexpected key in the variable_values dictionary -- the current behavior is that an ExecutionResult object is returned from the function, with the associated GraphQLError present inside it. Instead, this should be treated as a Request error, according to the spec, meaning that a GraphQLError should be raised from execute().

The GraphQL spec states:

Request errors
Request errors are raised before execution begins. This may occur due to a parse grammar or validation error in the requested document, an inability to determine which operation to execute, or invalid input values for variables.

This means that it is incorrect for the coerce_variable_values function to be returning a GraphQLError inside an ExecutionResult: https://github.com/graphql-python/graphql-core/blob/9dcf25e66f6ed36b77de788621cf50bab600d1d3/src/graphql/execution/values.py#L93-L99

doing so means that a response payload is returned containing both an "errors" key and a null "data" key. Again, this a violation of the spec:

If a request error is raised, execution does not begin and the data entry in the response must not be present. The errors entry must include the error.

Dominant language
Python
Stars
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Forks
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