Failure to generate `ApolloCodegenLib/JavaScriptBridge.swift:343: Precondition failed: Expected JavaScript array but found: undefined`

[trevor-holliday-instacart]

Question

I am working on migrating an Apollo setup from 0.48.0 to 1.0.0

I have setup a config file that reads as follows

{ "schemaName": "GraphQLSchema", "input": { "operationSearchPaths": [ "Dir1/**/*.graphql", "Dir2/**/*.graphql", "Dir3/**/*.graphql" ], "schemaSearchPaths": [ "**/*.graphqls" ] }, "output": { "testMocks": { "none": {} }, "schemaTypes": { "path": "./GraphQLSchema", "moduleType": { "swiftPackageManager": {} } }, "operations": { "inSchemaModule": {} } }, "schemaDownloadConfiguration": { "downloadMethod": { "introspection": { "endpointURL": "URL", "httpMethod": { "POST": {} }, "includeDeprecatedInputValues": false, "outputFormat": "SDL" } }, "downloadTimeout": 60, "headers": [ { "Authorization": "<TOKEN>" } ], "outputPath": "./schema.graphqls" } }

I am able to properly fetch the schema, and it is stored in the project. However, when I attempt to run generation it fails with ApolloCodegenLib/JavaScriptBridge.swift:343: Precondition failed: Expected JavaScript array but found: undefined.

I can see in the console using verbose that the CodegenLib is matching on proper graphql files.

I believe I have something wrong with my config file, but I am unsure what it is.

[calvincestari]

Hi @trevor-holliday-instacart, the config looks fine. If it's getting to the point of fetching the schema then the config has already been validated so it's not likely a value in the config file causing the error. The code in question (ApolloCodegenLib/JavaScriptBridge.swift:343) is at the point where the config has been validated, the schema and operations parsed by graphql-js and the Swift code generation engine is attempting to create the AST we feed into the output templates.

It's going to be something in the schema/operation that is unexpected. Are you able to share the schema/operations privately for us to debug? If you can then send it to me at calvin.cestari[at]apollographql.com and we'll take a look at it.

[trevor-holliday-instacart]

Hi @calvincestari , I am unsure if I am able to share the files yet. I will get back to you on that. Could it be something to do with custom scalars? I saw in the migration guide I needed to setup extensions for them, but I assumed that would be after the generation ran?

[calvincestari]

but I assumed that would be after the generation ran?

Correct, custom scalars will only be for you to handle once the generated files have been output already.

Given that you shared the JSON config I assume you're using the CLI at the moment? An alternative way for you to debug would be to use ApolloCodegenLib in a project that you can run with breakpoints to narrow down on exactly which part of the schema/operation it's failing at.

[trevor-holliday-instacart]

That sounds like a plan. Do you have a link for which project I should clone?

[calvincestari]

I don't think we have one readily available but I can probably put one together quickly. Let me see what I can do..

[trevor-holliday-instacart]

Could I just clone the main apollo repo and shim something in that way?

[calvincestari]

You could probably wrestle one of the codegen configuration tests into doing what you need.

[trevor-holliday-instacart]

Seeing what I can do. The Schema file is quite large and the operations are broken down across multiple files.

[calvincestari]

OK, here's a very quick project that uses a local schema/operation but you can substitute those with your own in-place - ManualCodegen.zip

[calvincestari]

Hi @trevor-holliday-instacart, have you had any success with debugging which part of the schema/operations is causing the issue? Was that sample project helpful?

[trevor-holliday-instacart]

Hi @calvincestari I got delayed working this portion up. I will close for this for now as the mock project will be able to assist me with debugging issues.