DEV: Make it possible to deprecate plugin outlet properties

app/assets/javascripts/discourse-loader.js

@@ -21,7 +21,8 @@ var define, requirejs;
         getProperties: Ember.getProperties,
         set: Ember.set,
         setProperties: Ember.setProperties,
-        computed: Ember.computed
+        computed: Ember.computed,
+        defineProperty: Ember.defineProperty
       },
       "@ember/object/computed": {
         alias: Ember.computed.alias,

app/assets/javascripts/discourse/components/plugin-connector.js.es6

@@ -1,5 +1,7 @@
 import Component from "@ember/component";
-import { observes } from "discourse-common/utils/decorators";
+import { defineProperty, computed } from "@ember/object";
+import deprecated from "discourse-common/lib/deprecated";
+import { buildArgsWithDeprecations } from "discourse/lib/plugin-connectors";
 
 export default Component.extend({
   init() {
@@ -9,10 +11,30 @@ export default Component.extend({
     this.set("layoutName", connector.templateName);
 
     const args = this.args || {};
-    Object.keys(args).forEach(key => this.set(key, args[key]));
+    Object.keys(args).forEach(key => {
+      defineProperty(
+        this,
+        key,
+        computed("args", () => (this.args || {})[key])
+      );
+    });
+
+    const deprecatedArgs = this.deprecatedArgs || {};
+    Object.keys(deprecatedArgs).forEach(key => {
+      defineProperty(
+        this,
+        key,
+        computed("deprecatedArgs", () => {
+          deprecated(`The ${key} property is deprecated, but is being used in ${this.layoutName}`);
+
+          return (this.deprecatedArgs || {})[key];
+        })
+      );
+    });
 
     const connectorClass = this.get("connector.connectorClass");
-    connectorClass.setupComponent.call(this, args, this);
+    const merged = buildArgsWithDeprecations(args, deprecatedArgs);
+    connectorClass.setupComponent.call(this, merged, this);
 
     this.set("actions", connectorClass.actions);
   },
@@ -24,12 +46,6 @@ export default Component.extend({
     connectorClass.teardownComponent.call(this, this);
   },
 
-  @observes("args")
-  _argsChanged() {
-    const args = this.args || {};
-    Object.keys(args).forEach(key => this.set(key, args[key]));
-  },
-
   send(name, ...args) {
     const connectorClass = this.get("connector.connectorClass");
     const action = connectorClass.actions[name];

app/assets/javascripts/discourse/components/plugin-outlet.js.es6

@@ -30,7 +30,7 @@ import Component from "@ember/component";
    The list of disabled plugins is returned via the `Site` singleton.
 
 **/
-import { renderedConnectorsFor } from "discourse/lib/plugin-connectors";
+import { renderedConnectorsFor, buildArgsWithDeprecations } from "discourse/lib/plugin-connectors";
 
 export default Component.extend({
   tagName: "span",
@@ -46,7 +46,7 @@ export default Component.extend({
     this._super(...arguments);
     const name = this.name;
     if (name) {
-      const args = this.args;
+      const args = buildArgsWithDeprecations(this.args || {}, this.deprecatedArgs || {});
       this.set("connectors", renderedConnectorsFor(name, args, this));
     }
   }

app/assets/javascripts/discourse/lib/plugin-connectors.js.es6

@@ -1,4 +1,5 @@
 import Site from "discourse/models/site";
+import deprecated from "discourse-common/lib/deprecated";
 
 let _connectorCache;
 let _rawConnectorCache;
@@ -109,3 +110,23 @@ export function rawConnectorsFor(outletName) {
   }
   return _rawConnectorCache[outletName] || [];
 }
+
+export function buildArgsWithDeprecations(args, deprecatedArgs) {
+  const output = {};
+
+  Object.keys(args).forEach(key => {
+    Object.defineProperty(output, key, { value: args[key] });
+  });
+
+  Object.keys(deprecatedArgs).forEach(key => {
+    Object.defineProperty(output, key, {
+      get() {
+        deprecated(`${key} is deprecated`);
+
+        return deprecatedArgs[key];
+      }
+    });
+  });
+
+  return output;
+}

app/assets/javascripts/discourse/templates/components/plugin-outlet.hbs

@@ -1,3 +1,3 @@
 {{#each connectors as |c|}}
-  {{plugin-connector connector=c args=args class=c.classNames tagName=connectorTagName}}
+  {{plugin-connector connector=c args=args deprecatedArgs=deprecatedArgs class=c.classNames tagName=connectorTagName}}
 {{/each}}