fix(opencode_server): ignore non-error stderr and detect early exit

- Do not treat informational stderr lines as startup failures; collect stderr output instead

This should fix #355

Author: sudo-tee

lua/opencode/opencode_server.lua

@@ -207,6 +207,9 @@ end
 function OpencodeServer:spawn(opts)
   opts = opts or {}
   local log = require('opencode.log')
+  local ready = false
+  local startup_failed = false
+  local startup_stderr = {}
 
   local cmd = {
     config.opencode_executable,
@@ -225,17 +228,28 @@ function OpencodeServer:spawn(opts)
 
   log.debug('spawn: starting opencode server with command: %s', vim.inspect(cmd))
 
+  local function fail_startup(err)
+    if ready or startup_failed then
+      return
+    end
+
+    startup_failed = true
+    self.spawn_promise:reject(err)
+    safe_call(opts.on_error, err)
+  end
+
   self.mode = 'serve'
   self.job = vim.system(cmd, {
     cwd = opts.cwd,
     stdout = function(err, data)
       if err then
-        safe_call(opts.on_error, err)
+        fail_startup(err)
         return
       end
       if data then
         local url = data:match('opencode server listening on ([^%s]+)')
-        if url then
+        if url and not ready then
+          ready = true
           self.url = url
           self.spawn_promise:resolve(self)
           safe_call(opts.on_ready, self.job, url)
@@ -245,23 +259,26 @@ function OpencodeServer:spawn(opts)
     end,
     stderr = function(err, data)
       if err then
-        self.spawn_promise:reject(err)
-        safe_call(opts.on_error, err)
+        fail_startup(err)
         return
       end
-      if data then
-        -- Filter out INFO/WARN/DEBUG log lines (not actual errors)
-        local log_level = data:match('^%s*(%u+)%s')
-        if log_level and (log_level == 'INFO' or log_level == 'WARN' or log_level == 'DEBUG') then
-          -- Ignore log lines, don't reject
-          return
-        end
-        -- Only reject on actual errors
-        self.spawn_promise:reject(data)
-        safe_call(opts.on_error, data)
+      if data and data ~= '' then
+        table.insert(startup_stderr, data)
+        log.debug('spawn: stderr output: %s', vim.inspect(data))
       end
     end,
   }, function(exit_opts)
+    if not ready and not startup_failed then
+      local stderr_output = table.concat(startup_stderr)
+      local startup_error = stderr_output ~= '' and stderr_output
+        or string.format(
+          'Opencode server exited before reporting ready state (code=%s, signal=%s)',
+          tostring(exit_opts and exit_opts.code),
+          tostring(exit_opts and exit_opts.signal)
+        )
+      fail_startup(startup_error)
+    end
+
     -- Clear fields if not already cleared by shutdown()
     self.job = nil
     self.url = nil

tests/unit/opencode_server_spec.lua

@@ -89,7 +89,7 @@ describe('opencode.opencode_server', function()
     assert.is_nil(server.handle)
   end)
 
-  it('calls on_error when stderr is triggered', function()
+  it('calls on_error when stderr callback receives an error', function()
     local called = { on_error = false }
     local opts_captured = {}
     vim.system = function(cmd, opts)
@@ -124,20 +124,90 @@ describe('opencode.opencode_server', function()
       end,
       on_error = function(err)
         called.on_error = true
-        assert.equals('some error', err)
+        assert.equals('stream error', err)
       end,
       on_exit = function()
         called.on_exit = true
       end,
     })
-    -- Simulate stderr after job is set
-    server.job.stderr(nil, 'some error')
+    -- Simulate stderr callback error after job is set
+    server.job.stderr('stream error', nil)
     vim.wait(100, function()
       return called.on_error
     end)
     assert.is_true(called.on_error)
   end)
 
+  it('ignores stderr output before ready when stdout later reports the server URL', function()
+    local called = { on_error = false }
+    local server = OpencodeServer.new()
+
+    vim.system = function(cmd, opts)
+      vim.schedule(function()
+        opts.stderr(nil, 'Performing one time database migration, may take a few minutes...\n')
+        opts.stderr(nil, 'sqlite-migration:100\n')
+        opts.stdout(nil, 'opencode server listening on http://127.0.0.1:7777')
+      end)
+
+      return { pid = 45, kill = function() end }
+    end
+
+    local resolved
+    server:spawn({
+      cwd = '.',
+      on_ready = function(_, url)
+        resolved = url
+      end,
+      on_error = function()
+        called.on_error = true
+      end,
+      on_exit = function() end,
+    })
+
+    vim.wait(100, function()
+      return resolved ~= nil
+    end)
+
+    assert.equals('http://127.0.0.1:7777', resolved)
+    assert.is_false(called.on_error)
+  end)
+
+  it('rejects startup if the process exits before reporting the server URL', function()
+    local called = { on_error = nil, on_exit = false }
+    local server = OpencodeServer.new()
+
+    vim.system = function(cmd, opts, on_exit)
+      vim.schedule(function()
+        opts.stderr(nil, 'Database migration failed.\n')
+        on_exit({ code = 1, signal = 0 })
+      end)
+
+      return { pid = 46, kill = function() end }
+    end
+
+    local promise = server:spawn({
+      cwd = '.',
+      on_ready = function()
+        called.on_ready = true
+      end,
+      on_error = function(err)
+        called.on_error = err
+      end,
+      on_exit = function()
+        called.on_exit = true
+      end,
+    })
+
+    local ok, err = pcall(function()
+      promise:wait(100)
+    end)
+
+    assert.is_false(ok)
+    assert.truthy(tostring(err):match('Database migration failed'))
+    assert.truthy(tostring(called.on_error):match('Database migration failed'))
+    assert.is_true(called.on_exit)
+  end)
+
   it('calls on_exit and clears fields when process exits', function()
     local called = { on_exit = false }
     local opts_captured = {}