Add support for provider-defined functions (#10013)

* Update provider to support provider functions

* Remove unused import

* Add ability to copy .go files in functions package into downstream

mmv1/provider/terraform/common~compile.yaml

@@ -102,6 +102,12 @@
 -%>
 '<%= dir -%>/<%= fname.delete_suffix(".erb") -%>': 'third_party/terraform/framework_models/<%= fname -%>'
 <% end -%>
+<%
+  Dir["third_party/terraform/functions/*.go.erb"].each do |file_path|
+    fname = file_path.split('/')[-1]
+-%>
+'<%= dir -%>/functions/<%= fname.delete_suffix(".erb") -%>': 'third_party/terraform/functions/<%= fname -%>'
+<% end -%>
 <%
   Dir["third_party/terraform/scripts/**/*.erb"].each do |file_path|
     fname = file_path.delete_prefix("third_party/terraform/")

mmv1/provider/terraform/common~copy.yaml

@@ -122,6 +122,13 @@
 '<%= dir -%>/envvar/<%= fname -%>': 'third_party/terraform/envvar/<%= fname -%>'
 <% end -%>
 
+<%
+  Dir["third_party/terraform/functions/*.go"].each do |file_path|
+    fname = file_path.split('/')[-1]
+-%>
+'<%= dir -%>/functions/<%= fname -%>': 'third_party/terraform/functions/<%= fname -%>'
+<% end -%>
+
 <%
   Dir["third_party/terraform/scripts/**/*.*"].each do |file_path|
     next if file_path.end_with?('.erb')

mmv1/third_party/terraform/functions/main.go

@@ -0,0 +1 @@
+package functions

mmv1/third_party/terraform/fwprovider/framework_provider.go.erb

@@ -6,6 +6,7 @@ import (
 
     "github.com/hashicorp/terraform-plugin-framework-validators/stringvalidator"
     "github.com/hashicorp/terraform-plugin-framework/datasource"
+    "github.com/hashicorp/terraform-plugin-framework/function"
     "github.com/hashicorp/terraform-plugin-framework/path"
     "github.com/hashicorp/terraform-plugin-framework/provider"
     "github.com/hashicorp/terraform-plugin-framework/provider/metaschema"
@@ -28,6 +29,7 @@ import (
 // Ensure the implementation satisfies the expected interfaces
 var (
     _ provider.ProviderWithMetaSchema = &FrameworkProvider{}
+    _ provider.ProviderWithFunctions  = &FrameworkProvider{}
 )
 
 // New is a helper function to simplify provider server and testing implementation.
@@ -294,5 +296,10 @@ func (p *FrameworkProvider) DataSources(_ context.Context) []func() datasource.D
 
 // Resources defines the resources implemented in the provider.
 func (p *FrameworkProvider) Resources(_ context.Context) []func() resource.Resource {
-    return nil
+	return nil
 }
+
+// Functions defines the provider functions implemented in the provider.
+func (p *FrameworkProvider) Functions(_ context.Context) []func() function.Function {
+	return nil
+}