GraphQLError: Syntax Error: Unexpected <EOF> when a file only contains commented out query/mutation

[capaj]

Describe the bug

/home/capaj/work-repos/4house/4house-fe-web/src/pages/pay/PayPage.gql
    GraphQLError: Syntax Error: Unexpected <EOF>.
        at syntaxError (/home/capaj/work-repos/4house/4house-fe-web/node_modules/g
raphql/error/syntaxError.js:15:10)
        at Parser.unexpected (/home/capaj/work-repos/4house/4house-fe-web/node_mod
ules/graphql/language/parser.js:1482:41)
        at Parser.parseDefinition (/home/capaj/work-repos/4house/4house-fe-web/nod
e_modules/graphql/language/parser.js:155:16)
        at Parser.many (/home/capaj/work-repos/4house/4house-fe-web/node_modules/g
raphql/language/parser.js:1537:26)
        at Parser.parseDocument (/home/capaj/work-repos/4house/4house-fe-web/node_
modules/graphql/language/parser.js:109:25)
        at Object.parse (/home/capaj/work-repos/4house/4house-fe-web/node_modules/
graphql/language/parser.js:36:17)
        at parseRawSDL (/home/capaj/work-repos/4house/4house-fe-web/node_modules/@
graphql-tools/load/index.cjs.js:507:41)
        at parseSource (/home/capaj/work-repos/4house/4house-fe-web/node_modules/@
graphql-tools/load/index.cjs.js:483:9)
        at /home/capaj/work-repos/4house/4house-fe-web/node_modules/@graphql-tools
/load/index.cjs.js:546:64
        at /home/capaj/work-repos/4house/4house-fe-web/node_modules/p-try/index.js
:4:10
        at new Promise (<anonymous>)
        at pTry (/home/capaj/work-repos/4house/4house-fe-web/node_modules/p-try/in
dex.js:3:37)
        at run (/home/capaj/work-repos/4house/4house-fe-web/node_modules/@graphql-
tools/load/node_modules/p-limit/index.js:24:18)
        at /home/capaj/work-repos/4house/4house-fe-web/node_modules/@graphql-tools
/load/node_modules/p-limit/index.js:46:18
    GraphQLError: Syntax Error: Unexpected <EOF>.
        at syntaxError (/home/capaj/work-repos/4house/4house-fe-web/node_modules/g
raphql/error/syntaxError.js:15:10)
        at Parser.unexpected (/home/capaj/work-repos/4house/4house-fe-web/node_mod
ules/graphql/language/parser.js:1482:41)
        at Parser.parseDefinition (/home/capaj/work-repos/4house/4house-fe-web/nod
e_modules/graphql/language/parser.js:155:16)
        at Parser.many (/home/capaj/work-repos/4house/4house-fe-web/node_modules/g
raphql/language/parser.js:1537:26)
        at Parser.parseDocument (/home/capaj/work-repos/4house/4house-fe-web/node_
modules/graphql/language/parser.js:109:25)
        at Object.parse (/home/capaj/work-repos/4house/4house-fe-web/node_modules/
graphql/language/parser.js:36:17)
        at parseRawSDL (/home/capaj/work-repos/4house/4house-fe-web/node_modules/@
graphql-tools/load/index.cjs.js:507:41)
        at parseSource (/home/capaj/work-repos/4house/4house-fe-web/node_modules/@
graphql-tools/load/index.cjs.js:483:9)
        at /home/capaj/work-repos/4house/4house-fe-web/node_modules/@graphql-tools
/load/index.cjs.js:546:64
        at /home/capaj/work-repos/4house/4house-fe-web/node_modules/p-try/index.js
:4:10
        at new Promise (<anonymous>)
        at pTry (/home/capaj/work-repos/4house/4house-fe-web/node_modules/p-try/in
dex.js:3:37)
        at run (/home/capaj/work-repos/4house/4house-fe-web/node_modules/@graphql-
tools/load/node_modules/p-limit/index.js:24:18)
        at /home/capaj/work-repos/4house/4house-fe-web/node_modules/@graphql-tools
/load/node_modules/p-limit/index.js:46:18

To Reproduce
Steps to reproduce the behavior:
just run codegen

1. My GraphQL schema:
   doesn't matter

2. My GraphQL operations:

# mutation payProduct($product: String!) {
#   createPaymentIntent(product: $product)
# }

3. My codegen.yml config file:
   doesn't matter
   Expected behavior
   no error

Environment:

• OS: ubutnut
• @graphql-codegen/...: 1.17.4
• NodeJS: 12

Additional context

commenting out a query/mutation should not cause codegen to fail. Maybe it could print a warning, but it should not fail.

[dotansimha]

Thank you for reporting this @capaj!
I guess we should try to check if it's possible to parse files and allow empty files in some cases.
@ardatan what do you think? is it something we can apply to the graphql-tools loaders?

[ardatan]

@capaj @dotansimha Instead of having an additional step on graphql-tools, I think graphql-js should return an empty DocumentNode in favor of this unreadable error. Do you agree?

[dotansimha]

@IvanGoncharov what do you think?
I think @ardatan is right, and graphql-js should parse empty strings (or, semi-empty strings, like in this example) as DocumentNode with zero definitions. Otherwise it makes is very hard for tools to detect this kind of input.

[danielrearden]

@dotansimha @ardatan I think this is related to graphql/graphql-js#2241 and could probably done as part of that work. Even if we upstream this to graphql-js, though, it means anyone needing the fix will need to update to graphql@16 or whatever version it ends up being. In the meantime, would it be sufficient to just do something like this?

function isEmpty(source: string) {
  return source.replace(/^ *#.*/g, '').trim().length === 0
}

[dotansimha]

Latest graphql-tools is now using a wrapped method for the parse process, which allow empty files to be handled.
I think this should solve this issue as well.

[dotansimha]

Ok I can confirm that #4553 fixed this issue as well.
Will be available in a new release very soon.

[dotansimha]

Fixed in latest version of our plugins. Please make sure to update cli/core to latest (1.17.8), it will update @graphql-tools/ deps, and will fix that issue as well!