fix(commands): ignore the nil line sent when the run output closes

lua/flutter-tools/commands.lua

@@ -54,9 +54,8 @@ local function set_current_device(device)
 end
 
 ---Resolve the device name from the `Launching ... on <device> in <mode> mode` output line
----@param line string|nil
+---@param line string
 local function update_device_from_output(line)
-  if not line then return end
   local name = line:match("^Launching .+ on (.+) in %w+ mode")
   if not name then return end
   local device = vim.tbl_extend("force", current_device or {}, { name = vim.trim(name) })
@@ -115,7 +114,9 @@ end
 
 ---Handle output from flutter run command
 ---@param is_err boolean if this is stdout or stderr
+---@param data string? nil once the job's output stream closes
 local function on_run_data(is_err, data)
+  if not data then return end
   if is_err and config.dev_log.notify_errors then queue_error_notification(data) end
   update_device_from_output(data)
   dev_log.log(data)

tests/commands_spec.lua

@@ -110,8 +110,19 @@ describe("commands", function()
     assert.is_nil(commands.current_device())
   end)
 
-  it("should not crash when output line is nil", function()
-    assert.has_no.errors(function() commands.__update_device_from_output(nil) end)
+  it("should ignore the nil line sent when the run output closes", function()
+    local config = require("flutter-tools.config")
+    config.dev_log.notify_errors = true
+    config.dev_log.filter = function(line) return not line:match("^D/") end
+
+    local ok, err = pcall(function()
+      commands.__on_run_data(false, nil)
+      commands.__on_run_data(true, nil)
+    end)
+
+    config.dev_log.notify_errors = false
+    config.dev_log.filter = nil
+    assert.is_true(ok, err)
   end)
 
   it("should batch consecutive error lines into one notification", function()