eslint: Incorrect indenting of ternary with multi-line function calls with offsetTernaryExpressions: true

updated:

Part 1a: Regression

Tell us about your environment

• ESLint Version: v7.19.0
• Node Version: v14.15.4
• npm Version: 6.14.10

What parser (default, @babel/eslint-parser, @typescript-eslint/parser, etc.) are you using?

default

Please show your full configuration:

Here is my .eslintrc.yml configuration from https://github.com/brodybits/react-native-module-init, but with Prettier plugin items removed I think they are not important for this issue:

parserOptions:
  ecmaVersion: 9

extends: standard

plugins:
  - jest

env: { jest/globals: true }

What did you do? Please include the actual source code causing the issue, as well as the command that you used to run ESLint.

I am raising this with a redaction of the affected source code from https://github.com/brodybits/react-native-module-init, which is not formatted right by eslint v7.19.0 as I said in https://github.com/brodybits/react-native-module-init/pull/90#issuecomment-770473490.

Here is the redaction of the affected source code that I have made in await-prompt1.js:

const prompts = require('prompts')

function onPromptState ({ aborted }) {
  if (aborted) {
    process.exit(1)
  }
}

function prompt (props) {
  return prompts([{ onState: onPromptState, ...props }])
}

Promise.resolve().then(async () => {
  const platforms = ['android', 'ios']

  const { androidPackageId } =
    platforms.indexOf('android') !== -1
      ? await prompt({
          type: 'text',
          name: 'androidPackageId',
          message: 'What is the desired Android package id?',
          initial: 'com.demo',
          validate: androidPackageId => androidPackageId.length > 0
        })
      : { androidPackageId: null }

  console.log({ androidPackageId })
})

npx eslint await-prompt1.js

What did you expect to happen?

Accepts the formatting as-is, like eslint 7.18.0

What actually happened? Please include the actual, raw output from ESLint.

/Users/brodybits/dev/react-native-module-init/await-prompt1.js
  19:1  error  Expected indentation of 8 spaces but found 10  indent
  20:1  error  Expected indentation of 8 spaces but found 10  indent
  21:1  error  Expected indentation of 8 spaces but found 10  indent
  22:1  error  Expected indentation of 8 spaces but found 10  indent
  23:1  error  Expected indentation of 8 spaces but found 10  indent
  24:1  error  Expected indentation of 6 spaces but found 8   indent

✖ 6 problems (6 errors, 0 warnings)
  6 errors and 0 warnings potentially fixable with the `--fix` option.

When I try npx eslint await-prompt1.js --fix, it changes the code like this:

--- await-prompt1.js.orig	2021-01-31 19:21:20.000000000 -0500
+++ await-prompt1.js	2021-01-31 19:32:02.000000000 -0500
@@ -16,12 +16,12 @@
   const { androidPackageId } =
     platforms.indexOf('android') !== -1
       ? await prompt({
-          type: 'text',
-          name: 'androidPackageId',
-          message: 'What is the desired Android package id?',
-          initial: 'com.demo',
-          validate: androidPackageId => androidPackageId.length > 0
-        })
+        type: 'text',
+        name: 'androidPackageId',
+        message: 'What is the desired Android package id?',
+        initial: 'com.demo',
+        validate: androidPackageId => androidPackageId.length > 0
+      })
       : { androidPackageId: null }
 
   console.log({ androidPackageId })

Are you willing to submit a pull request to fix this bug?

Yes (best effort)

This is regression is blocking https://github.com/standard/standard/issues/1624, which could have otherwise been resolved by the recent eslint 7.19.0 update.

I think this regression is caused by my contribution in https://github.com/eslint/eslint/pull/13972, which I should have tested on https://github.com/brodybits/react-native-module-init before submitting it for review.

Part 1b: General case - object reducer function

I have reproduced a more general manifestation of the issue with an object reducer function in tests/lib/rules/indent.js:

        {
            code: unIndent`
              condition1
                ? reduce({
                  first,
                  second,
                })
                : reduce({
                  third,
                  fourth,
                })
            `,
            options: [2, { offsetTernaryExpressions: true }]
        },

If I would revert the lib update in e1da90f (PR #13972), then this would be the expected indentation now unbalanced:

        {
            code: unIndent`
              condition1
                ? reduce({
                    first,
                    second,
                  })
                : reduce({
                  third,
                  fourth,
                })
            `,
            options: [2, { offsetTernaryExpressions: true }]
        },

Part 2: General case - pipe function

I have reproduced another more general manifestation with a pipe function in tests/lib/rules/indent.js:

        {
            code: unIndent`
              condition1
                ? pipe(
                  first,
                  second,
                )
                : pipe(
                  third,
                  fourth,
                )
            `,
            options: [2, { offsetTernaryExpressions: true }]
        },

This seems to be inconsistent with the expected formatting documented in: https://eslint.org/docs/rules/indent#offsetternaryexpressions

If I would revert the change to lib in e1da90fc414a3c9c16f52db4a5bd81bd4f9532a4 (PR #13972), then the expected indenting is shown as follows now unbalanced:

        {
            code: unIndent`
              condition1
                ? pipe(
                    first,
                    second,
                  )
                : pipe(
                  third,
                  fourth,
                )
            `,
            options: [2, { offsetTernaryExpressions: true }]
        },

which looks similar to closed issue #13425.