support force-cleaning git repos

'git clean -fd' should have the most reasonably expected result (files
in .gitignore are still ignored). This change is written to support
other cleaning methods in the future, if desired.

README.md

@@ -179,6 +179,22 @@ It only comes into effect if the revision parameter is different from the local
 
 **WARNING:** This overwrites any conflicting local changes to the repository.
 
+To remove untracked changes in the local repository, set `repository_status` to `default_clean`.
+
+~~~ puppet
+vcsrepo { '/path/to/repo':
+  ensure            => present,
+  provider          => git,
+  source            => 'git://example.com/repo.git',
+  repository_status => 'default_clean',
+}
+~~~
+
+The `default_clean` value directs vcsrepo to run `git clean -fd`, which does
+not affect files specified in the `.gitignore` file; future versions of
+vcsrepo may support other values for `repository_status`. Note that when this
+is in use, the `keep_local_changes` parameter has no net effect.
+
 To keep the repository at the latest revision, set `ensure` to 'latest':
 
 ~~~ puppet
@@ -797,7 +813,7 @@ For information on the classes and types, see the [REFERENCE.md](https://github.
 
 ##### `git` - Supports the Git VCS.
 
-Features: `bare_repositories`, `depth`, `multiple_remotes`, `reference_tracking`, `ssh_identity`, `submodules`, `user`
+Features: `bare_repositories`, `depth`, `multiple_remotes`, `reference_tracking`, `ssh_identity`, `submodules`, `user`, `working_copy_status'
 
 Parameters: `depth`, `ensure`, `excludes`, `force`, `group`, `identity`, `owner`, `path`, `provider`, `remote`, `revision`, `source`, `user`
 
@@ -852,6 +868,7 @@ Parameters: `basic_auth_password`, `basic_auth_username`, `configuration`, `conf
 * `ssh_identity` - Lets you specify an SSH identity file. (Available with `git` and `hg`.)
 * `submodules` - Supports repository submodules which can be optionally initialized. (Available with `git`.)
 * `user` - Can run as a different user. (Available with `git`, `hg` and `cvs`.)
+* `working_copy_status` - Can enforce the status of a working copy. (Available with `git`.)
 
 <a id="limitations"></a>
 ## Limitations

lib/puppet/provider/vcsrepo/git.rb

@@ -7,7 +7,7 @@
 
   has_features :bare_repositories, :reference_tracking, :ssh_identity, :multiple_remotes,
                :user, :depth, :branch, :submodules, :safe_directory, :hooks_allowed,
-               :umask, :http_proxy, :tmpdir
+               :umask, :http_proxy, :tmpdir, :repository_status
 
   def create
     check_force
@@ -72,6 +72,8 @@ def revision
   # @param [String] desired The desired revision to which the repo should be
   #                         set.
   def revision=(desired)
+    # Set the working copy status first
+    set_repository_status(@resource.value(:repository_status))
     # just checkout tags and shas; fetch has already happened so they should be updated.
     checkout(desired)
     # branches require more work.
@@ -232,6 +234,39 @@ def update_references
     end
   end
 
+  # Return the status of the working copy.
+  def repository_status
+    # Optimization: if we don't care about the status, then return right away.
+    # This avoids running 'git status', which may be costly on very large repos
+    # on slow, uncached filesystems.
+    if @resource.value(:repository_status) == :ignore
+      return :ignore
+    end
+
+    at_path do
+      # This allows files specified in .gitignore.
+      status = exec_git('status', '--porcelain')
+      return :default_clean if status.empty?
+      return :default_dirty
+    end
+  end
+
+  def repository_status=(desired)
+    set_repository_status(desired)
+  end
+
+  def set_repository_status(desired)
+    case desired
+    when :default_clean
+      at_path do
+        exec_git('clean', '-fd')
+      end
+    when :ignore
+    else
+      raise Puppet::Error, "Desired repository_status not implemented: #{desired}"
+    end
+  end
+
   # Convert working copy to bare
   #
   # Moves:

lib/puppet/type/vcsrepo.rb

@@ -76,6 +76,9 @@
   feature :tmpdir,
           'The provider supports setting the temp directory used for wrapper scripts.'
 
+  feature :repository_status,
+          'The provider supports setting the local repository status (to remove uncommitted local changes).'
+
   ensurable do
     desc 'Ensure the version control repository.'
     attr_accessor :latest
@@ -355,6 +358,20 @@ def insync?(is)
     desc 'The temp directory used for wrapper scripts.'
   end
 
+  newproperty :repository_status do
+    newvalue :default_clean
+    newvalue :ignore
+    defaultto :ignore
+
+    def insync?(is)
+      # unwrap @should
+      should = @should[0]
+      return true if should == :ignore
+      return true if is == should
+      false
+    end
+  end
+
   autorequire(:package) do
     ['git', 'git-core', 'mercurial', 'subversion']
   end

spec/unit/puppet/provider/vcsrepo/git_spec.rb

@@ -171,6 +171,34 @@ def branch_a_list(include_branch = nil?)
         provider.create
       end
     end
+
+    context 'when with an ensure of present - with repository_status of ignore' do
+      it "does not check the status" do
+        resource[:repository_status] = :ignore
+        expect(provider).to_not receive(:exec_git)
+        provider.repository_status
+      end
+
+      it "does not clean" do
+        expect(provider).to_not receive(:exec_git)
+        provider.repository_status=(:ignore)
+      end
+    end
+
+    context 'when with an ensure of present - with repository_status of default_clean' do
+      it "checks the status" do
+        resource[:repository_status] = :default_clean
+        expect(Dir).to receive(:chdir).with('/tmp/test').at_least(:once).and_yield
+        expect(provider).to receive(:exec_git).with('status', '--porcelain').and_return('')
+        provider.repository_status
+      end
+
+      it "cleans the repo" do
+        expect(Dir).to receive(:chdir).with('/tmp/test').at_least(:once).and_yield
+        expect(provider).to receive(:exec_git).with('clean', '-fd').and_return('')
+        provider.repository_status=(:default_clean)
+      end
+    end
   end
 
   context 'when with an ensure of bare' do