Missing closing brace in GQL input does not emit error

[lilyball]

Intended outcome:

I took one of my input GQL files and deleted a closing brace, then re-ran apollo client:codegen. I expected it to produce an error.

Actual outcome:

It succeeded just as if I had no error, except it skipped outputting a .graphql.swift file corresponding to the input file I modified.

How to reproduce the issue:

1. Take an existing project with multiple graphql input files
2. Edit one of the files and delete a closing brace somewhere. I did it at the end of a query, but I also tried deleting an interior brace and got the same behavior.
3. Run apollo client:codegen $outputDir --includes="*.graphql" --localSchemaFile=schema.json --target=swift

Versions

I've reproduced with both apollo/2.21.0 darwin-x64 node-v10.19.0 and a freshly-installed apollo/2.27.0 darwin-x64 node-v10.19.0.

[lilyball]

Validation errors such as missing fields emit an error properly. My assumption is parsing errors are just being silently skipped, but I didn't attempt to introduce any other parse errors, just the missing brace.

[JakeDawkins]

I believe #1899 should fix this! we were intentionally not erroring on syntax errors when setting up the project. I'm not 100% sure why we weren't, but I'm hesitant to change that now. Instead, I'm adding an error in the codegen command itself that should catch those errors.