Fix `add` method of `Selection` class

[jeanchambras]

Issue introduced with v1.5.1 (2023-05-15)

In the previous PR #17, modifications to the _subgrounds/pagination/preprocess.py_ file introduced the use of Selection.add at 2 locations, intended to conserve the outer Selection arguments while adding subselections. However, the add method failed to retain the arguments of the outer selection.

Affected code sections:

• Lines 272 to 282 in preprocess.py
• Lines 300 to 320 in preprocess.py

Impact: This issue results in the removal of all arguments that are not used in the pagination process. For example, the block (Block Height) argument, which allows selecting the block at which to return the data, is unintentionally removed. The queries are thus always run on the latest block available in the subgraph.

• Reproducible by for instance on an Ethereum Mainnet subgraph running a query with block = {"number" : 20000000} that do not fail and return the latest data available, while block 20000000 do not exist.

Fix: To address this issue, the following actions were taken:

• Filled missing arguments property in the Selection.add method to ensure the retention of outer selection arguments.
• Fixed tests to verify the logic of arguments in the Selection.add method.

This PR resolves the problem and ensures that the pagination process functions as intended, preserving the necessary arguments while adding subselections.

Recommandations:

• Add tests that use other arguments such as the block height. This time travel feature of subgraphs is super important and widely used. It must be checked before any release.
• Tests by filling all arguments of objects in unit tests such as the Selection.arguments to detect such issues.

[0xMochan]

Hey, somehow this completely slipped by radar! Thanks for the PR ❤️

[0xMochan]

I've reproduced with the aave-v2 subgraph from messari.

from subgrounds import Subgrounds
sg = Subgrounds()
aave_v2 = sg.load_subgraph("https://api.thegraph.com/subgraphs/name/messari/aave-v2-ethereum")

sg.query_df(aave_v2.Query.marketHourlySnapshots(first=10, block={"number": 20000000})

This code snippet, spits data out in current v1.6.0 while in this branch, it correctly outputs (matching GraphiQL):

GraphQLError: [{'message': 'Failed to decode `block.number` value: `subgraph Qmbte6tRTqFn9tf9LudDC9DLGnyKtqRqygXAUtj8FmKdye has only indexed up to block number 17823185 and data for block number 20000000 is therefore not yet available`'}]

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Thank you for finding this issue and this PR @jeanchambras!

In the future, do try to create an issue with specific code-snippets with replication details as it makes it easier for me to verify the problem and the solution. This fix was simple enough (unfortuntely slipped from my previous bug fix), so it wasn't too big of a deal.

[jeanchambras]

Understood thx for the recommandation and the quick react! Following next development closely 👀