"Error: duplicated mapping key" while reading YAML eslintrc file

We wanted to switch from an older version (1.10.3) to the current one (2.3.0). Our eslintrc is in Yaml and worked fine with the old ESLint version. When using it with 2.3.0 we get an error while ESLint tries to read the eslintrc:

YAMLException: Cannot read config file: /home/tom/code/foo/.eslintrc
Error: duplicated mapping key at line 52, column 3:
      no-func-assign:
      ^

The key is not duplicated in the file and there are no other config files in parent folders. When I converted the Yaml to a JSON file and used that, all worked fine.

Debug output of eslint --debug app/assets/javascripts/ spec/javascripts/:

  eslint:cli Running on files +0ms
  eslint:ignored-paths Looking for ignore file in /home/tom/code/foo +50ms
  eslint:ignored-paths Loaded ignore file /home/tom/code/foo/.eslintignore +1ms
  eslint:ignored-paths Adding /home/tom/code/foo/.eslintignore +0ms
  eslint:cli-engine Processing /home/tom/code/foo/app/assets/javascripts/application/admin/dashboard.js +11ms
  eslint:cli-engine Linting /home/tom/code/foo/app/assets/javascripts/application/admin/dashboard.js +1ms
  eslint:config Constructing config for /home/tom/code/foo/app/assets/javascripts/application/admin/dashboard.js +0ms
  eslint:config Using .eslintrc and package.json files +0ms
  eslint:config Loading /home/tom/code/foo/.eslintrc +1ms
  eslint:config-file Loading config file: /home/tom/code/foo/.eslintrc +1ms
  eslint:config-file Error reading YAML file: /home/tom/code/foo/.eslintrc +27ms
Cannot read config file: /home/tom/code/foo/.eslintrc
Error: duplicated mapping key at line 52, column 3:
      no-func-assign:
      ^
YAMLException: Cannot read config file: /home/tom/code/foo/.eslintrc
Error: duplicated mapping key at line 52, column 3:
      no-func-assign:
      ^
    at generateError (/usr/lib/node_modules/eslint/node_modules/js-yaml/lib/js-yaml/loader.js:162:10)
    at throwError (/usr/lib/node_modules/eslint/node_modules/js-yaml/lib/js-yaml/loader.js:168:9)
    at storeMappingPair (/usr/lib/node_modules/eslint/node_modules/js-yaml/lib/js-yaml/loader.js:305:7)
    at readBlockMapping (/usr/lib/node_modules/eslint/node_modules/js-yaml/lib/js-yaml/loader.js:1065:9)
    at composeNode (/usr/lib/node_modules/eslint/node_modules/js-yaml/lib/js-yaml/loader.js:1326:12)
    at readBlockMapping (/usr/lib/node_modules/eslint/node_modules/js-yaml/lib/js-yaml/loader.js:1056:11)
    at composeNode (/usr/lib/node_modules/eslint/node_modules/js-yaml/lib/js-yaml/loader.js:1326:12)
    at readDocument (/usr/lib/node_modules/eslint/node_modules/js-yaml/lib/js-yaml/loader.js:1488:3)
    at loadDocuments (/usr/lib/node_modules/eslint/node_modules/js-yaml/lib/js-yaml/loader.js:1544:5)
    at load (/usr/lib/node_modules/eslint/node_modules/js-yaml/lib/js-yaml/loader.js:1561:19)

ESLint version v2.3.0

full configuration

rules:
  indent:
    - 2
    - 2
  no-mixed-spaces-and-tabs:
    - 2
  quotes:
    - 2
    - "single"
    - "avoid-escape"
  linebreak-style:
    - 2
    - unix
  no-extra-semi:
    - 2
  no-redeclare:
    - 2
  no-unused-vars:
    - 2
  comma-dangle:
    - 2
  no-cond-assign:
    - 2
    - "always"
  no-console:
    - 2
  no-constant-condition:
    - 2
  no-control-regex:
    - 2
  no-debugger:
    - 2
  no-dupe-args:
    - 2
  no-dupe-keys:
    - 2
  no-duplicate-case:
    - 2
  no-empty-character-class:
    - 2
  no-empty:
    - 2
  no-ex-assign:
    - 2
  no-extra-boolean-cast:
    - 2
  no-extra-parens:
    - 2
    - "functions"
  no-extra-semi:
    - 2
  no-func-assign:
    - 2
  no-inner-declarations:
    - 2
  no-invalid-regexp:
    - 2
  no-irregular-whitespace:
    - 2
  no-negated-in-lhs:
    - 2
  no-obj-calls:
    - 2
  no-regex-spaces:
    - 2
  no-sparse-arrays:
    - 2
  no-unexpected-multiline:
    - 2
  no-unreachable:
    - 2
  use-isnan:
    - 2
  valid-jsdoc:
    - 2
  valid-typeof:
    - 2
  accessor-pairs:
    - 2
  block-scoped-var:
    - 2

env:
  browser: true
  jquery: true
# extends: 'eslint:recommended'

[mysticatea]

Thank you for this issue.

That error message seems to be confused. Actually, no-extra-semi is duplicated.

[nzakas]

There nothing we can do about this. It’s up to js-yaml to fix it, and if and when they do, it’ll get included in ESLint.