(PUP-9997) Pass cwd to execute method

Dir.chdir is problematic because it affects all threads in the current process
and if puppet is started with a current working directory it doesn't have
traverse/execute permission to, then it won't be able to restore the cwd at the
end of the Dir.chdir block.

Puppet supports three execution implementations: posix, windows and stub. The
first two already support the `cwd` option. Puppetserver injects its stub
implementation and it recently added support for `cwd`, see SERVER-3051.

Author: joshcooper

lib/puppet/parser/functions/generate.rb

@@ -31,7 +31,8 @@
   end
 
   begin
-    Dir.chdir(File.dirname(args[0])) { Puppet::Util::Execution.execute(args).to_str }
+    dir = File.dirname(args[0])
+    Puppet::Util::Execution.execute(args, failonfail: true, combine: true, cwd: dir).to_str
   rescue Puppet::ExecutionFailure => detail
     raise Puppet::ParseError, _("Failed to execute generator %{generator}: %{detail}") % { generator: args[0], detail: detail }, detail.backtrace
   end

spec/unit/parser/functions/generate_spec.rb

@@ -1,19 +1,39 @@
 require 'spec_helper'
 
+def with_executor
+  return yield unless Puppet::Util::Platform.jruby?
+
+  Puppet::Util::ExecutionStub.set do |command, options, stdin, stdout, stderr|
+    require 'open3'
+    # simulate what puppetserver does
+    Dir.chdir(options[:cwd]) do
+      out, err, _status = Open3.capture3(*command)
+      stdout.write(out)
+      stderr.write(err)
+      # execution api expects stdout to be returned
+      out
+    end
+  end
+  yield
+ensure
+  Puppet::Util::ExecutionStub.reset
+end
+
 describe "the generate function" do
   include PuppetSpec::Files
 
   let :node     do Puppet::Node.new('localhost') end
   let :compiler do Puppet::Parser::Compiler.new(node) end
   let :scope    do Puppet::Parser::Scope.new(compiler) end
+  let :cwd      do tmpdir('generate') end
 
   it "should exist" do
     expect(Puppet::Parser::Functions.function("generate")).to eq("function_generate")
   end
 
   it "accept a fully-qualified path as a command" do
     command = File.expand_path('/command/foo')
-    expect(Dir).to receive(:chdir).with(File.dirname(command)).and_return("yay")
+    expect(Puppet::Util::Execution).to receive(:execute).with([command], anything).and_return("yay")
     expect(scope.function_generate([command])).to eq("yay")
   end
 
@@ -35,33 +55,66 @@
   end
 
   it "should execute the generate script with the correct working directory" do
-    command = File.expand_path("/command")
-    expect(Dir).to receive(:chdir).with(File.dirname(command)).and_return("yay")
-    expect(scope.function_generate([command])).to eq('yay')
+    command = File.expand_path("/usr/local/command")
+    expect(Puppet::Util::Execution).to receive(:execute).with([command], hash_including(cwd: %r{/usr/local})).and_return("yay")
+    scope.function_generate([command])
+  end
+
+  it "should execute the generate script with failonfail" do
+    command = File.expand_path("/usr/local/command")
+    expect(Puppet::Util::Execution).to receive(:execute).with([command], hash_including(failonfail: true)).and_return("yay")
+    scope.function_generate([command])
+  end
+
+  it "should execute the generate script with combine" do
+    command = File.expand_path("/usr/local/command")
+    expect(Puppet::Util::Execution).to receive(:execute).with([command], hash_including(combine: true)).and_return("yay")
+    scope.function_generate([command])
+  end
+
+  it "executes a command in a working directory" do
+    if Puppet::Util::Platform.windows?
+      command = File.join(cwd, 'echo.bat')
+      File.write(command, <<~END)
+        @echo off
+        echo %CD%
+      END
+      expect(scope.function_generate([command]).chomp).to match(cwd.gsub('/', '\\'))
+    else
+      with_executor do
+        command = File.join(cwd, 'echo.sh')
+        File.write(command, <<~END)
+          #!/bin/sh
+          echo $PWD
+        END
+        Puppet::FileSystem.chmod(0755, command)
+        expect(scope.function_generate([command]).chomp).to eq(cwd)
+      end
+    end
   end
 
   describe "on Windows", :if => Puppet::Util::Platform.windows? do
     it "should accept the tilde in the path" do
       command = "C:/DOCUME~1/ADMINI~1/foo.bat"
-      expect(Dir).to receive(:chdir).with(File.dirname(command)).and_return("yay")
+      expect(Puppet::Util::Execution).to receive(:execute).with([command], hash_including(cwd: "C:/DOCUME~1/ADMINI~1")).and_return("yay")
       expect(scope.function_generate([command])).to eq('yay')
     end
 
     it "should accept lower-case drive letters" do
       command = 'd:/command/foo'
-      expect(Dir).to receive(:chdir).with(File.dirname(command)).and_return("yay")
+      expect(Puppet::Util::Execution).to receive(:execute).with([command], hash_including(cwd: "d:/command")).and_return("yay")
       expect(scope.function_generate([command])).to eq('yay')
     end
 
     it "should accept upper-case drive letters" do
       command = 'D:/command/foo'
-      expect(Dir).to receive(:chdir).with(File.dirname(command)).and_return("yay")
+      expect(Puppet::Util::Execution).to receive(:execute).with([command], hash_including(cwd: "D:/command")).and_return("yay")
       expect(scope.function_generate([command])).to eq('yay')
     end
 
     it "should accept forward and backslashes in the path" do
       command = 'D:\command/foo\bar'
-      expect(Dir).to receive(:chdir).with(File.dirname(command)).and_return("yay")
+      expect(Puppet::Util::Execution).to receive(:execute).with([command], hash_including(cwd: 'D:\command/foo')).and_return("yay")
       expect(scope.function_generate([command])).to eq('yay')
     end
 
@@ -81,7 +134,7 @@
 
     it "should accept plus and dash" do
       command = "/var/folders/9z/9zXImgchH8CZJh6SgiqS2U+++TM/-Tmp-/foo"
-      expect(Dir).to receive(:chdir).with(File.dirname(command)).and_return("yay")
+      expect(Puppet::Util::Execution).to receive(:execute).with([command], hash_including(cwd: '/var/folders/9z/9zXImgchH8CZJh6SgiqS2U+++TM/-Tmp-')).and_return("yay")
       expect(scope.function_generate([command])).to eq('yay')
     end
   end