properly handle empty text entry fields (including transformations)

sys/apps/Help.lua

@@ -81,7 +81,7 @@ function page:eventHandler(event)
 		end
 
 	elseif event.type == 'text_change' then
-		if #event.text == 0 then
+		if not event.text then
 			self.grid.values = topics
 		else
 			self.grid.values = { }

sys/apps/Lua.lua

@@ -153,10 +153,11 @@ function page:eventHandler(event)
 		self.tabs:selectTab(self.tabs[2])
 
 	elseif event.type == 'autocomplete' then
-		local sz = #self.prompt.value
+		local value = self.prompt.value or ''
+		local sz = #value
 		local pos = self.prompt.entry.pos
-		self:setPrompt(autocomplete(sandboxEnv, self.prompt.value, self.prompt.entry.pos))
-		self.prompt:setPosition(pos + #self.prompt.value - sz)
+		self:setPrompt(autocomplete(sandboxEnv, value, self.prompt.entry.pos))
+		self.prompt:setPosition(pos + #value - sz)
 		self.prompt:updateCursor()
 
 	elseif event.type == 'device' then
@@ -177,7 +178,7 @@ function page:eventHandler(event)
 		history:reset()
 
 	elseif event.type == 'command_enter' then
-		local s = tostring(self.prompt.value)
+		local s = tostring(self.prompt.value or '')
 
 		if #s > 0 then
 			self:executeStatement(s)

sys/apps/Welcome.lua

@@ -120,7 +120,9 @@ local page = UI.Page {
 }
 
 function page.wizard.pages.label:validate()
-	os.setComputerLabel(self.label.value)
+	if self.label.value then
+		os.setComputerLabel(self.label.value)
+	end
 	return true
 end
 

sys/apps/inspect.lua

@@ -6,11 +6,6 @@ local multishell = _ENV.multishell
 local name = ({ ... })[1] or error('Syntax: inspect COMPONENT')
 local events = { }
 local page
-local component = UI[name] and UI[name]() or error('Invalid component')
-
-if not component.example then
-	error('No example present')
-end
 
 local function isRelevant(el)
 	return page.testContainer == el or el.parent and isRelevant(el.parent)
@@ -18,8 +13,7 @@ end
 
 local emitter = UI.Window.emit
 function UI.Window:emit(event)
-	if not event.recorded and isRelevant(self) then
-		event.recorded = true
+	if not event._recorded and isRelevant(self) then
 		local t = { }
 		for k,v in pairs(event) do
 			if k ~= 'type' and k ~= 'recorded' then
@@ -35,9 +29,16 @@ function UI.Window:emit(event)
 			page.tabs.events.grid:draw()
 		end
 	end
+	event._recorded = true
 	return emitter(self, event)
 end
 
+-- do not load component until emit hook is in place
+local component = UI[name] and UI[name]() or error('Invalid component')
+if not component.example then
+	error('No example present')
+end
+
 page = UI.Page {
 	testContainer = UI.Window {
 		ey = 10,
@@ -122,7 +123,7 @@ page = UI.Page {
 			self.tabs.methodsTab.grid:draw()
 
 		elseif event.type == 'grid_select' and event.element == self.tabs.events.grid then
-			event.selected.raw.recorded = nil
+			event.selected.raw._recorded = nil
 			multishell.openTab({
 				path = 'sys/apps/Lua.lua',
 				args = { event.selected.raw },

sys/apps/system/label.lua

@@ -39,7 +39,7 @@ local labelTab = UI.Tab {
 }
 
 function labelTab:eventHandler(event)
-	if event.type == 'update_label' then
+	if event.type == 'update_label' and self.label.value then
 		os.setComputerLabel(self.label.value)
 		self:emit({ type = 'success_message', message = 'Label updated' })
 		return true

sys/apps/system/path.lua

@@ -59,7 +59,7 @@ function tab:save()
 end
 
 function tab:eventHandler(event)
-	if event.type == 'update_path' then
+	if event.type == 'update_path' and self.entry.value then
 		table.insert(self.grid.values, {
 			value = self.entry.value,
 		})