$ as value is considered variable, despite quotes

[insanitybit]

What version of Dgraph are you using?

Dgraph version : v1.1.0
Dgraph SHA-256 : 7d4294a80f74692695467e2cf17f74648c18087ed7057d798f40e1d3a31d2095
Commit SHA-1 : ef7cdb2
Commit timestamp : 2019-09-04 00:12:51 -0700
Branch : HEAD
Go version : go1.12.7

Name: pydgraph
Version: 2.0.2
Summary: Official Dgraph client implementation for Python
Home-page: https://github.com/dgraph-io/pydgraph
Author: Dgraph Labs
Author-email: contact@dgraph.io
License: Apache License, Version 2.0
Requires: grpcio, protobuf
Required-by:

Have you tried reproducing the issue with the latest release?

This is the latest 'standalone' release.

What is the hardware spec (RAM, OS)?

16GB RAM, 8 core intel.

Ubuntu 18.04.

Steps to reproduce the issue (command/config used to run Dgraph).

docker run --rm -it -p 8000:8000 -p 8080:8080 -p 9080:9080 dgraph/standalone:latest

Create a node with a predicate 'foo' and a value '$' .

Attempt to filter by $.

Here is an example query I have:

node_key = "test_process_query_view_parity_eqe3e70682-c209-4cac-629f-6fbed82c07cd"

query = f"""
    {{
        q0(func: eq(node_key, "{node_key}"))
        @filter(eq(process_name, "$"))
        {{
                uid,
                process_name
        }}
    }}

    """

json.loads(local_client.txn(read_only=True).query(query).json)

Or
@filter(eq(process_name, "\x24"))
@filter(eq(process_name, "\$))
@filter(eq(process_name, "\\$"))
etc

Expected behaviour and actual result.

I expect to see the predicate returned,The $ is quoted, so I don't expect it to do any kind of string interpolation (otherwise I'd just do the interpolation outside of the query and pass that in as a var).

I also do not see any documentation for escaping this parameter.

debug_error_string = "{"created":"@1580339274.335410834","description":"Error received from peer ipv6:[::1]:9080","file":"src/core/lib/surface/call.cc","file_line":1055,"grpc_message":"Variable not defined $","grpc_status":2}"

[insanitybit]

The recommendation seems to be to serialize $ as //$, and then deserialize //$ as $.
This seems to work, but it isn't documented anywhere and it seems like something that clients or the database should be handling.

I still think it's unexpected behavior for variables to work in quotes.

[poonai]

Hello @insanitybit ,

Thanks for reporting. We are working on a fix now.

I'll notify you, once the PR merges :)

[insanitybit]

Thank you @balajijinnah

[poonai]

@insanitybit PR merged 🎉