Defer loading view providers until activation or deserializer use

Signed-off-by: Nathan Sobo <nathan@github.com>

spec/fixtures/packages/package-with-view-providers/deserializer.js

@@ -0,0 +1,3 @@
+module.exports = function (state) {
+  return {state: state}
+}

spec/fixtures/packages/package-with-view-providers/package.json

@@ -2,6 +2,9 @@
   "name": "package-with-view-providers",
   "main": "./index",
   "version": "1.0.0",
+  "deserializers": {
+    "DeserializerFromPackageWithViewProviders": "./deserializer"
+  },
   "viewProviders": [
     "./view-provider-1",
     "./view-provider-2"

spec/package-manager-spec.coffee

@@ -96,20 +96,57 @@ describe "PackageManager", ->
 
       expect(pack.mainModule).toBeNull()
 
-    it "registers any view providers specified in the package's package.json", ->
-      pack = atom.packages.loadPackage("package-with-view-providers")
-
+    describe "when there are view providers specified in the package's package.json", ->
       model1 = {worksWithViewProvider1: true}
-      element1 = atom.views.getView(model1)
-      expect(element1 instanceof HTMLDivElement).toBe true
-      expect(element1.dataset.createdBy).toBe 'view-provider-1'
-
       model2 = {worksWithViewProvider2: true}
-      element2 = atom.views.getView(model2)
-      expect(element2 instanceof HTMLDivElement).toBe true
-      expect(element2.dataset.createdBy).toBe 'view-provider-2'
 
-      expect(pack.mainModule).toBeNull()
+      afterEach ->
+        atom.packages.deactivatePackage('package-with-view-providers')
+        atom.packages.unloadPackage('package-with-view-providers')
+
+      it "does not load the view providers immediately", ->
+        pack = atom.packages.loadPackage("package-with-view-providers")
+        expect(pack.mainModule).toBeNull()
+
+        expect(-> atom.views.getView(model1)).toThrow()
+        expect(-> atom.views.getView(model2)).toThrow()
+
+      it "registers the view providers when the package is activated", ->
+        pack = atom.packages.loadPackage("package-with-view-providers")
+
+        waitsForPromise ->
+          atom.packages.activatePackage("package-with-view-providers").then ->
+            element1 = atom.views.getView(model1)
+            expect(element1 instanceof HTMLDivElement).toBe true
+            expect(element1.dataset.createdBy).toBe 'view-provider-1'
+
+            element2 = atom.views.getView(model2)
+            expect(element2 instanceof HTMLDivElement).toBe true
+            expect(element2.dataset.createdBy).toBe 'view-provider-2'
+
+      it "registers the view providers when any of the package's deserializers are used", ->
+        pack = atom.packages.loadPackage("package-with-view-providers")
+
+        spyOn(atom.views, 'addViewProvider').andCallThrough()
+        atom.deserializers.deserialize({
+          deserializer: 'DeserializerFromPackageWithViewProviders',
+          a: 'b'
+        })
+        expect(atom.views.addViewProvider.callCount).toBe 2
+
+        atom.deserializers.deserialize({
+          deserializer: 'DeserializerFromPackageWithViewProviders',
+          a: 'b'
+        })
+        expect(atom.views.addViewProvider.callCount).toBe 2
+
+        element1 = atom.views.getView(model1)
+        expect(element1 instanceof HTMLDivElement).toBe true
+        expect(element1.dataset.createdBy).toBe 'view-provider-1'
+
+        element2 = atom.views.getView(model2)
+        expect(element2 instanceof HTMLDivElement).toBe true
+        expect(element2.dataset.createdBy).toBe 'view-provider-2'
 
     it "registers the config schema in the package's metadata, if present", ->
       pack = atom.packages.loadPackage("package-with-json-config-schema")

src/package.coffee

@@ -85,7 +85,6 @@ class Package
         @loadMenus()
         @loadStylesheets()
         @loadDeserializers()
-        @loadViewProviders()
         @registerConfigSchemaFromMetadata()
         @settingsPromise = @loadSettings()
         if @shouldRequireMainModuleOnLoad() and not @mainModule?
@@ -131,6 +130,7 @@ class Package
     try
       @requireMainModule() unless @mainModule?
       @registerConfigSchemaFromMainModule()
+      @registerViewProviders()
       @activateStylesheets()
       if @mainModule? and not @mainActivated
         @mainModule.activateConfig?()
@@ -279,16 +279,17 @@ class Package
           deserializeFunction = null
           atom.deserializers.add
             name: name,
-            deserialize: ->
+            deserialize: =>
+              @registerViewProviders()
               deserializeFunction ?= require(deserializePath)
               deserializeFunction.apply(this, arguments)
       return
 
-  loadViewProviders: ->
-    if @metadata.viewProviders?
+  registerViewProviders: ->
+    if @metadata.viewProviders? and not @registeredViewProviders
       for implementationPath in @metadata.viewProviders
         @viewRegistry.addViewProvider(require(path.join(@path, implementationPath)))
-      return
+      @registeredViewProviders = true
 
   getStylesheetsPath: ->
     path.join(@path, 'styles')