We'll want to be able to access RPC/WebSockets from other nodes that we deploy.

Currently while running the-graph-wasm compile data-source.yaml the script looks for a file called mapping.ts in the root directory, even if a different file path is specified in the data source definition.

Function names, number of parameters for all exported host functions called by WASM.

Error

When generating the TypeScript types for Decentraland's LAND Marketplace, the type generator fails to properly parse an empty input name in the ABI, which represents a public getter for a mapping:

Marketplace.sol

mapping (uint256 => Auction) public auctionByAssetId;

Marketplace.json

{
    "constant": true,
    "inputs": [
      {
        "name": "",
        "type": "uint256"
      }
    ],
    "name": "auctionByAssetId",
    "outputs": [
      {
        "name": "id",
        "type": "bytes32"
      },
      {
        "name": "seller",
        "type": "address"
      },
      {
        "name": "price",
        "type": "uint256"
      },
      {
        "name": "expiresAt",
        "type": "uint256"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  },

Error Message

$ the-graph-wasm generate-types --output-dir types/ data-source.yaml
[1/3] Load data source: data-source.yaml
[2/3] Load contract ABIs
Load contract ABI file: abis/Marketplace.json
[3/3] Generate types for contract ABIs
Generate types for contract ABI: Marketplace.json
Failed to generate types for contract ABI: { SyntaxError: Parameter declaration expected. (65:20)
  63 |   }
  64 | 
> 65 |   auctionByAssetId(: U256): Marketplace__auctionByAssetIdResult {let __result = super.call(
     |                    ^
  66 |                    'auctionByAssetId',
  67 |                    [Token.fromU256()]
  68 |                  )
    at e (/Users/aklempner/Repos/Graph/decentraland-mapping/the-graph-wasm/examples/example-event-handler/node_modules/the-graph-wasm/node_modules/prettier/parser-typescript.js:1:329)
    at Object.parse (/Users/aklempner/Repos/Graph/decentraland-mapping/the-graph-wasm/examples/example-event-handler/node_modules/the-graph-wasm/node_modules/prettier/parser-typescript.js:1:1844304)
    at Object.parse$2 [as parse] (/Users/aklempner/Repos/Graph/decentraland-mapping/the-graph-wasm/examples/example-event-handler/node_modules/the-graph-wasm/node_modules/prettier/index.js:7000:19)
    at coreFormat (/Users/aklempner/Repos/Graph/decentraland-mapping/the-graph-wasm/examples/example-event-handler/node_modules/the-graph-wasm/node_modules/prettier/index.js:10196:23)
    at format (/Users/aklempner/Repos/Graph/decentraland-mapping/the-graph-wasm/examples/example-event-handler/node_modules/the-graph-wasm/node_modules/prettier/index.js:10367:16)
    at formatWithCursor (/Users/aklempner/Repos/Graph/decentraland-mapping/the-graph-wasm/examples/example-event-handler/node_modules/the-graph-wasm/node_modules/prettier/index.js:10379:12)
    at /Users/aklempner/Repos/Graph/decentraland-mapping/the-graph-wasm/examples/example-event-handler/node_modules/the-graph-wasm/node_modules/prettier/index.js:31222:15
    at Object.format (/Users/aklempner/Repos/Graph/decentraland-mapping/the-graph-wasm/examples/example-event-handler/node_modules/the-graph-wasm/node_modules/prettier/index.js:31241:12)
    at TypeGenerator._generateTypesForABI (/Users/aklempner/Repos/Graph/decentraland-mapping/the-graph-wasm/examples/example-event-handler/node_modules/the-graph-wasm/cli-lib/type-generator.js:95:36)
    at abis.map (/Users/aklempner/Repos/Graph/decentraland-mapping/the-graph-wasm/examples/example-event-handler/node_modules/the-graph-wasm/cli-lib/type-generator.js:83:43)

Reproducing

git clone [email protected]:graphprotocol/the-graph-wasm.git
cd the-graph-wasm
git checkout decentraland-mapping
yarn
cd examples/decentraland
yarn
yarn build

It seems we currently depend on the latest master of AssemblyScript, which is scary since the way we pass data around is coupled with the Asc ABI which could change at any moment. We should pinpoint our Asc version, even if it's to a commit hash.

We want to group all the param fields under a params getter so that they cannot collide with (overwrite) event data like the event's block hash, address etc.

I get the following error when attempting to run yarn codegen with the ParamChange.json ABI from Memefactory included in my project:

Failed to generate types for contract ABI: Unsupported Value to type coercion for type: string

LANDRegistry has two functions with the name exists but with different param types. Running yarn codegen produces this error:

ERROR TS2300: Duplicate identifier 'index/LANDRegistry#exists'.

   exists(assetId: U256): bool {
   ~~~~~~
 in index.ts(693,2)

For instance, there are cases where we'll need to take a U256 and convert it to an address via either Token.fromU256(value).toAddress() or directly from value.toAddress().

This is required for the MemeFactory data source.

There are situations where developers will want to hard-code contract addresses in mappings, in order to bind them with e.g.

let contract = SomeContract.bind(Address.fromString("0x..."), event.blockHash)
...

However, there no way to convert from a string to an address in our mappings.

Currently we have to add type references like this

It would be better if we could include these references in a tsconfig file so the mappings files can remain cleaner.

We can create types like

type SomethingEnum {
  FOO,
  BAR,
}

type Band extends Entity {
   ... property getters ...
   ... property setters only for the fields that exist and are not derived ...
}

These need to convert the little-endian representations of i8, i16, i32, i64, u8, u16, u32, u64 to big-endian representations of I256 and U256.

• Initialize project directory with generic files: subgraph.yaml, package.json, schema.graphql, tsconfig.json.
• Create the ./mappings and ./abis directories with a single file in each?
• Files contain usage instructions in comment block on top?

Leo - please coordinate with Nena on the common set of contributing guidelines that are not rust-specific (she's writing them for the Typescript repo).

Livepeer reported that their contracts BondingManager and RoundsManager share some types, causing a name conflict when the ABIs of both contracts are added to a same mapping. The best solution would be to namespace the types by contract, but in this case since the types are equal de-duplicating would suffice.

Right now, after each change to a mapping, the developer has to complete the following steps:

• Generate types to write your mappings
• Compile your subgraph and mappings
• Deploy your subgraph manifest to IPFS
• Deploy your subgraph to Graph Node
  It would be much better if this could all be done in a single step during development and if that command could be executed on save.

This way the mappings won't have to do Value::from... everywhere.

It looks like Number can be i64, u64 or f64 in Rust, so we should probably have toI64, toI64 and toF64 variants (if the latter is possible in WASM) with type conversions in Rust (typeConversion.jsonNumberToI64 etc.).

Reproducing

git clone [email protected]:graphprotocol/the-graph-wasm.git
cd the-graph-wasm
git checkout marketplace-mapping-error
yarn
cd examples/decentraland
yarn
yarn build

Error Message

yarn build
yarn run v1.3.2
warning package.json: No license field
warning ../../package.json: No license field
$ the-graph-wasm compile data-source.yaml
[1/10] Load data source: data-source.yaml
[2/10] Create build directory
[3/10] Copy data source to build directory
Copy data source file: schema.graphql
Copy data source file: abis/Marketplace.json
Copy data source file: mapping.ts
[4/10] Generate types from contract ABIs
..... [1/3] Load data source
..... [2/3] Load contract ABIs
..... [3/3] Generate types for contract ABIs
..... Generate types for contract ABI: Marketplace.json
..... Write types to: Marketplace.types.ts
[5/10] Copy runtime to build directory
Copy runtime file: index.ts
[6/10] Add generated types to runtime
Add types from file to runtime: Marketplace.types.ts
[7/10] Add mapping to runtime
[8/10] Create output directory: /Users/aklempner/Repos/Graph/decentraland-mapping/the-graph-wasm/examples/decentraland/dist
[9/10] Compile data source
Compile data set mapping: Marketplace / mapping.ts

<--- Last few GCs --->

[24775:0x102801e00]    11261 ms: Mark-sweep 1296.9 (1355.3) -> 1296.6 (1360.8) MB, 971.1 / 0.0 ms  allocation failure GC in old space requested
[24775:0x102801e00]    12162 ms: Mark-sweep 1296.6 (1360.8) -> 1296.6 (1323.3) MB, 900.9 / 0.0 ms  last resort GC in old space requested
[24775:0x102801e00]    13008 ms: Mark-sweep 1296.6 (1323.3) -> 1296.6 (1323.3) MB, 845.6 / 0.0 ms  last resort GC in old space requested


<--- JS stacktrace --->

==== JS stack trace =========================================

Security context: 0x12daf8f257c1 <JSObject>
    1: /* anonymous */ [/Users/aklempner/Repos/Graph/decentraland-mapping/the-graph-wasm/examples/decentraland/node_modules/the-graph-wasm/node_modules/assemblyscript/dist/assemblyscript.js:~1] [pc=0x30b42e662d7b](this=0x12da8d102749 <t map = 0x12da9da87e21>,e=0x12da1807c099 <t map = 0x12da9da888c9>)
    2: /* anonymous */ [/Users/aklempner/Repos/Graph/decentraland-mapping/the-graph-wasm/example...

FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory
 1: node::Abort() [/Users/aklempner/.nvm/versions/node/v8.11.1/bin/node]
 2: node::FatalException(v8::Isolate*, v8::Local<v8::Value>, v8::Local<v8::Message>) [/Users/aklempner/.nvm/versions/node/v8.11.1/bin/node]
 3: v8::internal::V8::FatalProcessOutOfMemory(char const*, bool) [/Users/aklempner/.nvm/versions/node/v8.11.1/bin/node]
 4: v8::internal::Factory::NewUninitializedFixedArray(int) [/Users/aklempner/.nvm/versions/node/v8.11.1/bin/node]
 5: v8::internal::(anonymous namespace)::ElementsAccessorBase<v8::internal::(anonymous namespace)::FastPackedObjectElementsAccessor, v8::internal::(anonymous namespace)::ElementsKindTraits<(v8::internal::ElementsKind)2> >::GrowCapacity(v8::internal::Handle<v8::internal::JSObject>, unsigned int) [/Users/aklempner/.nvm/versions/node/v8.11.1/bin/node]
 6: v8::internal::Runtime_GrowArrayElements(int, v8::internal::Object**, v8::internal::Isolate*) [/Users/aklempner/.nvm/versions/node/v8.11.1/bin/node]
 7: 0x30b42e4842fd
 8: 0x30b42e662d7b
 9: 0x30b42e66b0a4
10: 0x30b42e48535f
11: 0x30b42e645af8
✨  Done in 13.26s.

For this, we'll want to have a Database.bind(blockHash): Database function that gives us an object with create, update, delete functions that send the block hash along.

Current idea: Use an Array<TypedMapEntry> where TypedMapEntry { key: T, value: V } to represent the key/value pairs. This way we can piggieback on the existing Array implementation in AssemblyScript.

WASM-only solution

There’s an easy solution that’s purely on the WASM side: We could generate

class AuctionCreatedEvent extends EthereumEvent {
  id(): Bytes { return this.params[0].value }
  assetId(): H256 { return this.params[1].value }
  seller(): string { return this.params[2].value }
}

When people then write handlers like

handleAuctionCreatedEvent(event: AuctionCreatedEvent) { ... }

they could use event.id(), event.seller(). (edited)
That requires no magic at all in Rust.

Rust solution

We could try using generics like

Event1<T>
Event2<T,U>
Event3<T,U,V>
...

and write Asc type conversions for the. The names of the parameters don't matter, just their order and their types.