Disable eslint if no config is found

Fixes and closes GH-1085

CHANGES.rst

@@ -9,6 +9,8 @@
     no longer used [GH-1057]
   - ``:modes`` is now mandatory for syntax checker definitions [GH-1071]
   - Remove jade checker [GH-951] [GH-1084]
+  - Remove ``javascript-eslintrc`` and instead rely on eslint's own configuration file
+    search [GH-1085]
 
 - New syntax checkers:
 
@@ -22,6 +24,10 @@
     subcommand [GH-1079]
   - Add ``:enabled`` property to ``flycheck-define-checker`` [GH-1089]
 
+- Improvements:
+
+  - Do not use ``javascript-eslint`` if eslint cannot find a valid configuration [GH-1085]
+
 29 (Aug 28, 2016)
 =================
 

doc/languages.rst

@@ -549,12 +549,15 @@ to view the docstring of the syntax checker.  Likewise, you may use
 
       Check syntax and lint with `ESLint <http://eslint.org/>`_.
 
+      .. note::
+
+         Flycheck does not use this syntax checker if eslint cannot find a valid
+         configuration file.
+
       .. defcustom:: flycheck-eslint-rules-directories
 
          A list of directories with custom rules.
 
-      .. syntax-checker-config-file:: flycheck-eslintrc
-
    .. syntax-checker:: javascript-jshint
 
       Check syntax and lint with `JSHint <http://jshint.com/>`_.

flycheck.el

@@ -7489,16 +7489,11 @@ for more information about the custom directories."
   :safe #'flycheck-string-list-p
   :package-version '(flycheck . "29"))
 
-(flycheck-def-config-file-var flycheck-eslintrc javascript-eslint nil
-  :safe #'stringp
-  :package-version '(flycheck . "0.20"))
-
 (flycheck-define-checker javascript-eslint
   "A Javascript syntax and style checker using eslint.
 
 See URL `https://github.com/eslint/eslint'."
   :command ("eslint" "--format=checkstyle"
-            (config-file "--config" flycheck-eslintrc)
             (option-list "--rulesdir" flycheck-eslint-rules-directories)
             "--stdin" "--stdin-filename" source-original)
   :standard-input t
@@ -7518,6 +7513,14 @@ See URL `https://github.com/eslint/eslint'."
                                    (flycheck-error-message err))))
                           (flycheck-sanitize-errors errors))
                   errors)
+  :enabled (lambda (checker)
+             (let* ((directory (concat
+                                (flycheck-compute-working-directory checker)
+                                "."))
+                    (executable (flycheck-find-checker-executable checker))
+                    (exitcode (call-process executable nil nil nil
+                                            "--print-config" directory)))
+               (eq exitcode 0)))
   :modes (js-mode js-jsx-mode js2-mode js2-jsx-mode js3-mode)
   :next-checkers ((warning . javascript-jscs)))
 

test/flycheck-test.el

@@ -3321,17 +3321,16 @@ Why not:
   (let ((flycheck-disabled-checkers '(javascript-jshint)))
     (flycheck-ert-should-syntax-check
      "language/javascript/syntax-error.js" flycheck-test-javascript-modes
-     '(3 26 error "Parsing error: Unexpected token )" :checker javascript-eslint))))
+     '(3 25 error "Parsing error: Unexpected token )" :checker javascript-eslint))))
 
 (flycheck-ert-def-checker-test javascript-eslint javascript warning
   :tags '(checkstyle-xml)
-  (let ((flycheck-eslintrc "eslint.json")
-        (flycheck-disabled-checkers '(javascript-jshint javascript-jscs)))
+  (let ((flycheck-disabled-checkers '(javascript-jshint javascript-jscs)))
     (flycheck-ert-should-syntax-check
      "language/javascript/warnings.js" flycheck-test-javascript-modes
-     '(3 2 warning "Use the function form of \"use strict\"." :id "strict"
+     '(3 2 warning "Use the function form of 'use strict'." :id "strict"
          :checker javascript-eslint)
-     '(4 9 warning "\"foo\" is defined but never used" :id "no-unused-vars"
+     '(4 9 warning "'foo' is defined but never used." :id "no-unused-vars"
          :checker javascript-eslint))))
 
 (flycheck-ert-def-checker-test javascript-gjslint javascript nil

test/resources/language/javascript/.eslintrc.json

@@ -0,0 +1,6 @@
+{
+  "rules" : {
+    "strict": 1,
+    "no-unused-vars": 1
+  }
+}