Introduce partial search similar to Rails (#2467)

Introduce partial search similar to Rails. Models that have an inheritance
relationship often use similar or almost identical partials.
Being able to reuse partials not only makes it easier to create new fields,
but also improves maintainability.

Developers who want to provide alternative templates can override
`local_partial_prefixes`.
---------

Co-authored-by: Pablo Brasero <pablo@pablobm.com>

Author: goosys

app/helpers/administrate/application_helper.rb

@@ -9,7 +9,15 @@ def application_title
 
     def render_field(field, locals = {})
       locals[:field] = field
-      render locals: locals, partial: field.to_partial_path
+      if (prefix = find_partial_prefix(field))
+        render locals: locals, partial: "#{prefix}/#{field.page}"
+      end
+    end
+
+    def find_partial_prefix(field)
+      field.partial_prefixes.detect do |prefix|
+        lookup_context.template_exists?(field.page, [prefix], true)
+      end
     end
 
     def requireness(field)

lib/administrate/field/base.rb

@@ -36,6 +36,19 @@ def self.permitted_attribute(attr, _options = nil)
         attr
       end
 
+      def self.partial_prefixes
+        @partial_prefixes ||=
+          if superclass.respond_to?(:partial_prefixes)
+            local_partial_prefixes + superclass.partial_prefixes
+          else
+            local_partial_prefixes
+          end
+      end
+
+      def self.local_partial_prefixes
+        ["fields/#{field_type}"]
+      end
+
       def initialize(attribute, data, page, options = {})
         @attribute = attribute
         @page = page
@@ -70,8 +83,8 @@ def read_value(data)
         end
       end
 
-      def to_partial_path
-        "/fields/#{self.class.field_type}/#{page}"
+      def partial_prefixes
+        self.class.partial_prefixes
       end
 
       def required?

spec/administrate/views/fields/has_one/_show_spec.rb

@@ -35,7 +35,8 @@
         name: "simple_string_field",
         truncate: "string value",
         html_class: "string",
-        to_partial_path: "fields/string/index"
+        page: "index",
+        partial_prefixes: ["fields/string"]
       )
 
       nested_show_page_for_has_one = instance_double(
@@ -123,7 +124,8 @@ def render_field
         data: nested_collection,
         html_class: "has-many",
         name: "payments",
-        to_partial_path: "fields/has_many/index"
+        page: "index",
+        partial_prefixes: ["fields/has_many"]
       )
 
       nested_show_page_for_nested_has_one = instance_double(
@@ -141,7 +143,8 @@ def render_field
         linkable?: true,
         nested_show: nested_show_page_for_nested_has_one,
         html_class: "has-one",
-        to_partial_path: "fields/has_one/show",
+        page: "show",
+        partial_prefixes: ["fields/has_one"],
         display_associated_resource: "Resource Doubly Nested with HasOne",
         name: "page"
       )

spec/example_app/app/views/fields/has_many_variant/_form.html.erb

@@ -1,6 +1,24 @@
 require "rails_helper"
+require "administrate/field/has_many"
+require "administrate/field/has_many_variant"
 
 RSpec.describe Administrate::ApplicationHelper do
+  describe "#find_partial_prefix" do
+    context "when the field has a partial" do
+      it "returns the prefix" do
+        field = Administrate::Field::HasMany.new(:name, "hello", :show)
+        expect(find_partial_prefix(field)).to eq("fields/has_many")
+      end
+    end
+
+    context "when the field does not have a partial and the superclass does" do
+      it "returns the superclass prefix" do
+        field = Administrate::Field::HasManyVariant.new(:name, "hello", :show)
+        expect(find_partial_prefix(field)).to eq("fields/has_many")
+      end
+    end
+  end
+
   describe "#display_resource_name" do
     it "defaults to the plural of the model name" do
       displayed = display_resource_name(:customer)

spec/example_app/app/views/fields/has_many_variant/_index.html.erb

@@ -26,15 +26,15 @@
     end
   end
 
-  describe "#to_partial_path" do
+  describe "#partial_prefixes" do
     it "returns a partial based on the page being rendered" do
       page = :show
       owner = double
       field = Administrate::Field::BelongsTo.new(:owner, owner, page)
 
-      path = field.to_partial_path
+      prefixes = field.partial_prefixes
 
-      expect(path).to eq("/fields/belongs_to/#{page}")
+      expect(prefixes).to eq(["fields/belongs_to", "fields/associative", "fields/base"])
     end
   end
 

spec/example_app/app/views/fields/has_many_variant/_show.html.erb

@@ -5,15 +5,15 @@
 describe Administrate::Field::Boolean do
   include FieldMatchers
 
-  describe "#to_partial_path" do
+  describe "#partial_prefixes" do
     it "returns a partial based on the page being rendered" do
       page = :show
       boolean = double
       field = Administrate::Field::Boolean.new(:price, boolean, page)
 
-      path = field.to_partial_path
+      prefixes = field.partial_prefixes
 
-      expect(path).to eq("/fields/boolean/#{page}")
+      expect(prefixes).to eq(["fields/boolean", "fields/base"])
     end
   end
 

spec/helpers/administrate/application_helper_spec.rb

@@ -1,14 +1,14 @@
 require "administrate/field/email"
 
 describe Administrate::Field::Email do
-  describe "#to_partial_path" do
+  describe "#partial_prefixes" do
     it "returns a partial based on the page being rendered" do
       page = :show
       field = Administrate::Field::Email.new(:email, "foo@example.com", page)
 
-      path = field.to_partial_path
+      prefixes = field.partial_prefixes
 
-      expect(path).to eq("/fields/email/#{page}")
+      expect(prefixes).to eq(["fields/email", "fields/base"])
     end
   end
 end