fix (graphql): disallowing field names with as

[aman-bansal]

Signed-off-by: aman-bansal bansalaman2905@gmail.com
This is related to GRAPHQL-564. as is Dgraph reserved keyword. It's being used by DQL to identify variables. This PR is to restrict the naming for fields with the name as.

Though interesting things have been found while working on this. There is a difference in how we check as keyword while query parsing. For example, in normal DQL queries, the parser uses this strings.ToLower(peekIt[0].Val) == "as" (dgraph/gql/parser.go:2552) this means as, As, AS, aS all are the same.

But while parsing facets, its been treated like this !trySkipItemVal(it, "as") (dgraph/gql/parser.go:1984).

Though having a different use case, keyword significance is the same. Would love to hear thoughts about these implementations.

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[abhimanyusinghgaur]

we also have a @dgraph(type: "", pred: "") directive, using which one can override the GraphQL generated name for any field or type. I think that also needs to have this restriction.

@ashish-goswami can say more about its usage in facets.

Reviewed 1 of 2 files at r1.
Reviewable status: 1 of 2 files reviewed, 1 unresolved discussion (waiting on @aman-bansal, @danielmai, @MichaelJCompton, and @pawanrawal)

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wiki/content/graphql/schema/reserved.md, line 10 at r1 (raw file):

Names `Int`, `Float`, `Boolean`, `String`, `DateTime` and `ID` are reserved and cannot be used to define any other identifiers.
Similarly, Names like `uid`, `Subscription`, `as`, `Query` and `Mutation` are also reserved and cannot be used to define any other Identifiers.

Maybe just combine the two lines, or state it all like:

The following names are reserved and can't be used to define any other identifiers:
* Int
* Float
...
* as/As/aS/AS
* Query
...

[abhimanyusinghgaur]

Nice work!

Sorry, I should have pointed it the last time itself, but we also need to add tests for the same. Have a look in graphql/schema/gqlschema_test.yml and just add invalid_schemas using as at all the different places, i.e., as a type name, field name, and the same cases with @dgraph.

Reviewed 2 of 2 files at r2.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @danielmai, @MichaelJCompton, and @pawanrawal)

[abhimanyusinghgaur]

Reviewable status: 2 of 3 files reviewed, all discussions resolved (waiting on @abhimanyusinghgaur, @danielmai, @MichaelJCompton, and @pawanrawal)

[abhimanyusinghgaur]

Actually, the target branch should be master.