Fix calculation of scoped setting defaults

lib/settings-panel.js

@@ -165,15 +165,23 @@ export default class SettingsPanel extends CollapsibleSectionPanel {
   }
 
   getDefault (name) {
+    let params = {excludeSources: [atom.config.getUserConfigPath()]}
     if (this.options.scopeName != null) {
-      return atom.config.get(name)
-    } else {
-      let params = {excludeSources: [atom.config.getUserConfigPath()]}
-      if (this.options.scopeName != null) {
-        params.scope = [this.options.scopeName]
+      params.scope = [this.options.scopeName]
+    }
+
+    let defaultValue = atom.config.get(name, params)
+    if (this.options.scopeName != null) {
+      // If the unscoped default is the same as the scoped default, check the actual config.cson
+      // to make sure that there isn't a non-default value that is overriding the scoped value
+      // For example: the default editor.tabLength is 2, but if someone sets it to 4
+      // the above check still returns 2 and not 4 for a scoped editor.tabLength,
+      // because it bypasses config.cson.
+      if (atom.config.get(name, {excludeSources: [atom.config.getUserConfigPath()]}) === defaultValue) {
+        defaultValue = atom.config.get(name)
       }
-      return atom.config.get(name, params)
     }
+    return defaultValue
   }
 
   set (name, value) {
@@ -210,11 +218,7 @@ export default class SettingsPanel extends CollapsibleSectionPanel {
       let type = editorElement.getAttribute('type')
 
       if (defaultValue = this.valueToString(this.getDefault(name))) {
-        if (this.options.scopeName != null) {
-          editor.setPlaceholderText(`Unscoped value: ${defaultValue}`)
-        } else {
-          editor.setPlaceholderText(`Default: ${defaultValue}`)
-        }
+        editor.setPlaceholderText(`Default: ${defaultValue}`)
       }
 
       const subscriptions = new CompositeDisposable()

spec/settings-panel-spec.coffee

@@ -109,21 +109,46 @@ describe "SettingsPanel", ->
       settingsPanel.set('foo.testZero', 0)
       expect(settingsPanel.isDefault('foo.testZero')).toBe true
 
-    describe 'when displaying scoped settings', ->
-      it 'displays the settings unscoped value of a setting as its default', ->
+    describe 'scoped settings', ->
+      beforeEach ->
+        schema =
+          scopes:
+            '.source.python':
+              default: 4
+
+        atom.config.setScopedDefaultsFromSchema('editor.tabLength', schema)
         expect(atom.config.get('editor.tabLength')).toBe(2)
+
+      it 'displays the scoped default', ->
+        settingsPanel = new SettingsPanel({namespace: "editor", includeTitle: false, scopeName: '.source.python'})
+        tabLengthEditor = settingsPanel.element.querySelector('[id="editor.tabLength"]')
+        expect(tabLengthEditor.getModel().getText()).toBe('')
+        expect(tabLengthEditor.getModel().getPlaceholderText()).toBe('Default: 4')
+
+      it 'allows the scoped setting to be changed to its normal default if the unscoped value is different', ->
         atom.config.set('editor.tabLength', 8)
 
         settingsPanel = new SettingsPanel({namespace: "editor", includeTitle: false, scopeName: '.source.js'})
         tabLengthEditor = settingsPanel.element.querySelector('[id="editor.tabLength"]')
         expect(tabLengthEditor.getModel().getText()).toBe('')
-        expect(tabLengthEditor.getModel().getPlaceholderText()).toBe('Unscoped value: 8')
+        expect(tabLengthEditor.getModel().getPlaceholderText()).toBe('Default: 8')
 
-        # This is the default value, but it differs from the unscoped value
+        # This is the unscoped default, but it differs from the current unscoped value
         settingsPanel.set('editor.tabLength', 2)
         expect(tabLengthEditor.getModel().getText()).toBe('2')
         expect(atom.config.get('editor.tabLength', {scope: ['source.js']})).toBe(2)
 
+      it 'allows the scoped setting to be changed to the unscoped default if it is different', ->
+        settingsPanel = new SettingsPanel({namespace: "editor", includeTitle: false, scopeName: '.source.python'})
+        tabLengthEditor = settingsPanel.element.querySelector('[id="editor.tabLength"]')
+        expect(tabLengthEditor.getModel().getText()).toBe('')
+        expect(tabLengthEditor.getModel().getPlaceholderText()).toBe('Default: 4')
+
+        # This is the unscoped default, but it differs from the scoped default
+        settingsPanel.set('editor.tabLength', 2)
+        expect(tabLengthEditor.getModel().getText()).toBe('2')
+        expect(atom.config.get('editor.tabLength', {scope: ['source.python']})).toBe(2)
+
   describe 'grouped settings', ->
     beforeEach ->
       config =