Ignore exit codes from "npm list --json" as they can be misleading

lib/puppet/provider/package/npm.rb

@@ -8,12 +8,14 @@
   optional_commands :npm => 'npm'
 
   def self.npmlist
+    # Ignore non-zero exit codes as they can be minor, just try and parse JSON
+    output = execute([command(:npm), 'list', '--json', '--global'], {:combine => false})
+    Puppet.debug("Warning: npm list --json exited with code #{$CHILD_STATUS.exitstatus}") unless $CHILD_STATUS.success?
     begin
-      output = npm('list', '--json', '--global')
       # ignore any npm output lines to be a bit more robust
       output = PSON.parse(output.lines.select{ |l| l =~ /^((?!^npm).*)$/}.join("\n"))
       @npmlist = output['dependencies'] || {}
-    rescue Exception => e
+    rescue PSON::ParserError => e
       Puppet.debug("Error: npm list --json command error #{e.message}")
       @npmlist = {}
     end

spec/unit/puppet/provider/pakages/npm_spec.rb

@@ -3,12 +3,13 @@
 
 describe Puppet::Type.type(:package).provider(:npm) do
   before :each do
-    @provider.class.stubs(:optional_commands).with(:npm).returns "/usr/local/bin/npm"
     @resource =  Puppet::Type.type(:package).new(
       :name   => 'express',
       :ensure => :present
     )
     @provider = described_class.new(@resource)
+    @provider.class.stubs(:optional_commands).with(:npm).returns "/usr/local/bin/npm"
+    @provider.class.stubs(:command).with(:npm).returns "/usr/local/bin/npm"
   end
 
   def self.it_should_respond_to(*actions)
@@ -37,13 +38,31 @@ def self.it_should_respond_to(*actions)
   end
 
   describe "when npm packages are installed globally" do
+    before :each do
+      @provider.class.instance_variable_set(:@npmlist, nil)
+    end
+
     it "should return a list of npm packages installed globally" do
-      @provider.class.stubs(:npm).with('list', '--json', '--global').returns(my_fixture_read('npm_global'))
+      @provider.class.expects(:execute).with(['/usr/local/bin/npm', 'list', '--json', '--global'], anything).returns(my_fixture_read('npm_global'))
       @provider.class.instances.map {|p| p.properties}.sort_by{|res| res[:name]}.should == [
         {:ensure => '2.5.9' , :provider => 'npm', :name => 'express'},
         {:ensure => '1.1.15', :provider => 'npm', :name => 'npm'    },
       ]
     end
+
+    it "should log and continue if the list command has a non-zero exit code" do
+      @provider.class.expects(:execute).with(['/usr/local/bin/npm', 'list', '--json', '--global'], anything).returns(my_fixture_read('npm_global'))
+      Process::Status.any_instance.expects(:success?).returns(false)
+      Process::Status.any_instance.expects(:exitstatus).returns(123)
+      Puppet.expects(:debug).with(regexp_matches(/123/))
+      @provider.class.instances.map {|p| p.properties}.should_not == []
+    end
+
+    it "should log and return no packages if JSON isn't output" do
+      @provider.class.expects(:execute).with(['/usr/local/bin/npm', 'list', '--json', '--global'], anything).returns("failure!")
+      Puppet.expects(:debug).with(regexp_matches(/npm list.*failure!/))
+      @provider.class.instances.should == []
+    end
   end
 
 #  describe "when no npm packages are installed globally" do