Skip single characters was not printed. Please report this error!

[ahsanrana]

when ever i try to format my js file , it gives me this error
["ERROR" - 10:30:02 PM] Error formatting document.
["ERROR" - 10:30:02 PM] Comment "Skip single characters" was not printed. Please report this error!

[kachkaev]

Please use the issue template to help us reproduce the bug. What source code was producing the error?

[ns-vpanfilov]

@kachkaev, I also have the same issue in typescript file after I updated to prettier 3.0.0 from 2.8.8

const a = {
  project: "SchemaCheck.String()",

  ns_dcs: [
    "SchemaCheck.StringArray()",
    (props:any) => {
      const val = props.value as string[]
      if (val.length == 2) return undefined // return success
      else return { message: 'array must include 2 items' }
    },
  ],  
}

output in vscode:

["INFO" - 1:30:39 PM] Formatting file:///home/op/packages/base-lib/src/coreTypes/messageTypes/ezDemoGre.ts
["INFO" - 1:30:39 PM] Using config file at '/home/op/packages/base-lib/.prettierrc.js'
["INFO" - 1:30:39 PM] PrettierInstance:
{
  "modulePath": "/home/op/node_modules/prettier/index.cjs",
  "importResolver": {},
  "callMethodResolvers": {},
  "currentCallMethodId": 79,
  "version": "3.0.0"
}
["INFO" - 1:30:39 PM] Using ignore file (if present) at /home/op/packages/base-lib/.prettierignore
["INFO" - 1:30:39 PM] File Info:
{
  "ignored": false,
  "inferredParser": "typescript"
}
["INFO" - 1:30:39 PM] Detected local configuration (i.e. .prettierrc or .editorconfig), VS Code configuration will not be used
["INFO" - 1:30:39 PM] Prettier Options:
{
  "filepath": "/home/op/packages/base-lib/src/coreTypes/messageTypes/ezDemoGre.ts",
  "parser": "typescript",
  "arrowParens": "always",
  "bracketSpacing": true,
  "bracketSameLine": false,
  "jsxSingleQuote": true,
  "printWidth": 100,
  "quoteProps": "consistent",
  "rangeStart": 0,
  "rangeEnd": null,
  "semi": false,
  "singleQuote": true,
  "tabWidth": 2,
  "trailingComma": "es5",
  "useTabs": false,
  "endOfLine": "lf"
}
["ERROR" - 1:30:39 PM] Error formatting document.
["ERROR" - 1:30:39 PM] Comment "return success" was not printed. Please report this error!
Error: Comment "return success" was not printed. Please report this error!
    at ensureAllCommentsPrinted (file:///home/op/node_modules/prettier/index.mjs:17941:13)
    at printAstToDoc (file:///home/op/node_modules/prettier/index.mjs:18102:3)
    at async coreFormat (file:///home/op/node_modules/prettier/index.mjs:18405:14)
    at async formatWithCursor (file:///home/op/node_modules/prettier/index.mjs:18603:14)
    at async Module.format2 (file:///home/op/node_modules/prettier/index.mjs:21789:25)
["INFO" - 1:30:39 PM] Formatting completed in 13ms.

[MatanelGordon]

Ok I think I got the problem.

playground link

The Code in Question:

const a = {
  project: "SchemaCheck.String()",

  ns_dcs: [
    "SchemaCheck.StringArray()",
    (props:any) => {
      const val = props.value as string[]
      if (val.length == 2) return undefined // return success
      else return { message: 'array must include 2 items' }
    },
  ],  
}

Result

So by formatting the former coed using prettier playground, I received the following error:

Error: Comment "return success" was not printed. Please report this error!
    at pu (https://prettier.io/lib/standalone.js:27:5829)
    at Ze (https://prettier.io/lib/standalone.js:27:7320)
    at async Ou (https://prettier.io/lib/standalone.js:27:11026)
    at async Rr (https://prettier.io/lib/standalone.js:32:581)
    at async formatCode (https://prettier.io/worker.js:170:12)
    at async handleFormatMessage (https://prettier.io/worker.js:82:24)
    at async self.onmessage (https://prettier.io/worker.js:37:14)

This error specifically refers to the one-line comment "return success" being adjacent to a real return statement.

Solution: Curly brackets

by adding curly brackets to the if-statement I was able to successfully run prettier

The Code

const f = (props:any) => {
  const val = props.value as string[]
  if (val.length == 2){
        return undefined // return success
  }
  else return { message: 'array must include 2 items' }
}

The Reason - trying to prettify the comment as code because of "return ..."

I think Prettier thinks the comment is a code incorrectly. Might be a bug in the breakdown to AST of single-line comments in single-line If-statements.

Edit: @kachkaev That should give you more than enough info to take it from here 😄

[christiango]

I'm also seeing this and sharing my source code in case it helps :). This code results in a Error: Comment "Already locked from a previous run, so return early." was not printed. Please report this error!

    if (dataStorePageViewsInitLocked) return; // Already locked from a previous run, so return early.