fix(GraphQL): This PR addd input coercion from single object to list and fix panic when we pass single ID in filter as a string.

[JatinDev543]

Fixes GRAPHQL-745
Filter with id as a string was giving panic because we were expecting it to be of ["0x1"] type.

 query {
        queryAuthor(filter:{id: "0x1"}) {
          name
          }
        }

So, we added input coercion such that if we require an object of type list and the input object is scalar then we coerce it to list.

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This change is 

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[pawanrawal]

Reviewed 9 of 9 files at r1.
Reviewable status: 8 of 9 files reviewed, 2 unresolved discussions (waiting on @jatindevdg, @manishrjain, @MichaelJCompton, @pawanrawal, and @vvbalaji-dgraph)

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go.sum, line 126 at r1 (raw file):

github.com/dgraph-io/gqlgen v0.13.2/go.mod h1:iCOrOv9lngN7KAo+jMgvUPVDlYHdf7qDwsTkQby2Sis=
github.com/dgraph-io/gqlparser/v2 v2.1.1 h1:OBGI6VR+WcegjDB3JdNPMpKpEtITHWzgmiCXtELWolI=
github.com/dgraph-io/gqlparser/v2 v2.1.1/go.mod h1:MYS4jppjyx8b9tuUtjV7jU1UFZK6P9fvO8TsIsQtRKU=

Run go mod tidy

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graphql/schema/validation_rules.go, line 37 at r1 (raw file):

		}
		// ExpectedType.Elem will be not nil if it is of list type. Otherwise
		// it will be nil. So it's safe to say that value.Kind should be list

Rephrase the comment as

If the expected value is a list (ExpectedType.Elem != nil) && the value is not of list type, then we need to coerce the value to a list, otherwise, we can return here as we do below.

[JatinDev543]

Reviewable status: 7 of 9 files reviewed, 2 unresolved discussions (waiting on @manishrjain, @MichaelJCompton, @pawanrawal, and @vvbalaji-dgraph)

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go.sum, line 126 at r1 (raw file):

Previously, pawanrawal (Pawan Rawal) wrote…

Run go mod tidy

manually removed this. go mod tidy has no effect.

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graphql/schema/validation_rules.go, line 37 at r1 (raw file):

Previously, pawanrawal (Pawan Rawal) wrote…

Rephrase the comment as

If the expected value is a list (ExpectedType.Elem != nil) && the value is not of list type, then we need to coerce the value to a list, otherwise, we can return here as we do below.

done.