Fix uncaught error 'ENOENT'. See #3 and steelbrain/linter#330

lib/linter-rust.coffee

@@ -3,37 +3,42 @@ Linter = require "#{linterPath}/lib/linter"
 
 {exec} = require 'child_process'
 {log, warn} = require "#{linterPath}/lib/utils"
+fs = require 'fs'
 path = require 'path'
 
 
 class LinterRust extends Linter
-  @enable: false
+  @enabled: false
   @syntax: 'source.rust'
+  @rustcPath: ''
   linterName: 'rust'
   errorStream: 'stderr'
   regex: '(.+):(?<line>\\d+):(?<col>\\d+):\\s*(\\d+):(\\d+)\\s+((?<error>error|fatal error)|(?<warning>warning)|(?<info>note)):\\s+(?<message>.+)\n'
 
   constructor: (@editor) ->
     super @editor
     atom.config.observe 'linter-rust.executablePath', =>
-      @executablePath = atom.config.get 'linter-rust.executablePath'
-      exec "#{@executablePath} --version", @executionCheckHandler
+      rustcPath = atom.config.get 'linter-rust.executablePath'
+      if rustcPath != @rustcPath
+        @enabled = false
+        @rustcPath = rustcPath
+        exec "#{@rustcPath} --version", @executionCheckHandler
 
   executionCheckHandler: (error, stdout, stderr) =>
     versionRegEx = /rustc ([\d\.]+)/
     if not versionRegEx.test(stdout)
       result = if error? then '#' + error.code + ': ' else ''
       result += 'stdout: ' + stdout if stdout.length > 0
       result += 'stderr: ' + stderr if stderr.length > 0
-      console.error "Linter-Rust: \"#{@executablePath}\" was not executable: \
+      console.error "Linter-Rust: \"#{@rustcPath}\" was not executable: \
       \"#{result}\". Please, check executable path in the linter settings."
     else
       @enabled = true
       log "Linter-Rust: found rust " + versionRegEx.exec(stdout)[1]
       do @initCmd
 
   initCmd: =>
-    @cmd = "#{@executablePath} -Z no-trans --color never"
+    @cmd = "#{@rustcPath} -Z no-trans --color never"
     log 'Linter-Rust: initialization completed'
 
   lintFile: (filePath, callback) =>