Fix #1088 - Collections overrides

This changeset defines a new syntax to override collection
of resources (virtual or not). This feature is not constrained
to the override in inherited context as usual resource
override.
The collection of resource supports a query like regular collection
of virtual or exported resources.

Usage example:
file {
    "/tmp/testing": content => "whatever"
}

File<| |> {
    mode => 0600
}

It also introduces a different behaviour for collection of catalog
resources. Before this patch, only virtual resources were collected,
now all resources (virtual or no) are collected and can be overriden.

That means it is now possible to do:
File <| |> { mode => 0600 }
And all the Files resources will have mode 0600.

It is then possible to have this puppet pattern:
file { "/tmp/a": content => "a" }
file { "/tmp/b": content => "b" }

File <| title != "/tmp/a" |> {
    require => File["/tmp/b"]
}
which means that every File requires a file.

Moreover it is now possible to define resource overriding
without respecting the override on inheritance rule:

class a {
    file {
        "/tmp/testing": content => "whatever"
    }
}

class b {
    include a
    File<| |> {
        mode => 0600
    }
}
include b

Signed-off-by: Brice Figureau <brice-puppet@daysofwonder.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/lib/puppet/parser/ast/collection.rb b/lib/puppet/parser/ast/collection.rb
index a51b9b4d2..55e99fc08 100644
--- a/lib/puppet/parser/ast/collection.rb
+++ b/lib/puppet/parser/ast/collection.rb
@@ -7,6 +7,7 @@ require 'puppet/parser/collector'
 class Puppet::Parser::AST
 class Collection < AST::Branch
     attr_accessor :type, :query, :form
+    attr_reader :override
 
     associates_doc
 
@@ -22,7 +23,37 @@ class Collection < AST::Branch
 
         scope.compiler.add_collection(newcoll)
 
+        # overrides if any
+        # Evaluate all of the specified params.
+        if @override
+            params = @override.collect do |param|
+                param.safeevaluate(scope)
+            end
+
+            newcoll.add_override(
+                :params => params,
+                :file => @file,
+                :line => @line,
+                :source => scope.source,
+                :scope => scope
+            )
+        end
+
         newcoll
     end
+
+    # Handle our parameter ourselves
+    def override=(override)
+        if override.is_a?(AST::ASTArray)
+            @override = override
+        else
+            @override = AST::ASTArray.new(
+                :line => override.line,
+                :file => override.file,
+                :children => [override]
+            )
+        end
+    end
+
 end
 end