No se puede actualizar de 2.5.0beta2 a 2.6.0beta1

Primero hago clic en la interfaz de administración para actualizar docker_manager, y funciona durante un tiempo hasta que veo esto:

Done compressing docker-manager-vendor-91af87077979e715f4d5034ea05c612f734c3aece05878051e901d07e84878ee.js : 0.17 secs

Skipping: plugins/docker_manager-25504a87a4e36bcc8a621591ad8ca39652edee1eb267254e2d16758445970569.js already compressed
Skipping: vendor-6298e12c042d341b1c8aa26fa7c82ff8866b7acee80cdea5b8c6f37a4cea7f79.js already compressed
Skipping: admin-9e3b6ba79e00d1ef15a26ef708754cad4bf9bac15086239cf3298865d5b747b3.js already compressed
Skipping: preload-store-d32dcf974dddcac742f8a7a6aa7fcd686185920b201029d0ecb2b85527ef9034.js already compressed
26081353.78273959 Compressing: ember_jquery-8e338e1cfe17986203b8367e20408d23399e209fb3a0d86cbd8f98e499a037a9.js
uglifyjs '/var/www/discourse/public/assets/_ember_jquery-8e338e1cfe17986203b8367e20408d23399e209fb3a0d86cbd8f98e499a037a9.js' -m -c -o '/var/www/discourse/public/assets/ember_jquery-8e338e1cfe17986203b8367e20408d23399e209fb3a0d86cbd8f98e499a037a9.js' --source-map "base='/var/www/discourse/public/assets',root='/assets',url='/assets/ember_jquery-8e338e1cfe17986203b8367e20408d23399e209fb3a0d86cbd8f98e499a037a9.js.map'"
WARN: Condition left of && always false [/var/www/discourse/public/assets/_ember_jquery-8e338e1cfe17986203b8367e20408d23399e209fb3a0d86cbd8f98e499a037a9.js:10797,8]
WARN: Dropping side-effect-free statement [/var/www/discourse/public/assets/_ember_jquery-8e338e1cfe17986203b8367e20408d23399e209fb3a0d86cbd8f98e499a037a9

Después de eso aparecen una serie de advertencias similares (junto con algunas advertencias de «efecto secundario»), seguidas de esto:

WARN: Dropping side-effect-free statement [/var/www/discourse/public/assets/_ember_jquery-8e338e1cfe17986203b8367e20408d23399e209fb3a0d86cbd8f98e499a037a9.js:68041,8]
fs.js:114
    throw err;
    ^

Error: ENOENT: no such file or directory, open 'base='/var/www/discourse/public/assets',root='/assets',url='/assets/ember_jquery-8e338e1cfe17986203b8367e20408d23399e209fb3a0d86cbd8f98e499a037a9.js.map''
    at Object.openSync (fs.js:443:3)
    at Object.writeFileSync (fs.js:1194:35)
    at done (/usr/lib/node_modules/uglify-js/bin/uglifyjs:516:20)
    at cb (/usr/lib/node_modules/uglify-js/bin/uglifyjs:324:39)
    at /usr/lib/node_modules/uglify-js/bin/uglifyjs:391:9
    at FSReqWrap.readFileAfterClose [as oncomplete] (internal/fs/read_file_context.js:53:3)
rake aborted!
Errno::ENOENT: No such file or directory @ rb_file_s_size - /var/www/discourse/public/assets/ember_jquery-8e338e1cfe17986203b8367e20408d23399e209fb3a0d86cbd8f98e499a037a9.js
/var/www/discourse/lib/tasks/assets.rake:270:in `size'
/var/www/discourse/lib/tasks/assets.rake:270:in `block (4 levels) in <top (required)>'
/var/www/discourse/lib/tasks/assets.rake:161:in `block in concurrent?'
/var/www/discourse/lib/tasks/assets.rake:261:in `block (3 levels) in <top (required)>'
/var/www/discourse/lib/tasks/assets.rake:252:in `each'
/var/www/discourse/lib/tasks/assets.rake:252:in `block (2 levels) in <top (required)>'
/var/www/discourse/lib/tasks/assets.rake:161:in `concurrent?'
/var/www/discourse/lib/tasks/assets.rake:249:in `block in <top (required)>'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rake-13.0.1/exe/rake:27:in `<top (required)>'
/usr/local/bin/bundle:23:in `load'
/usr/local/bin/bundle:23:in `<main>'
Tasks: TOP => assets:precompile
(See full trace by running task with --trace)
Docker Manager: FAILED TO UPGRADE
#<RuntimeError: RuntimeError>
/var/www/discourse/plugins/docker_manager/lib/docker_manager/upgrader.rb:167:in `run'
/var/www/discourse/plugins/docker_manager/lib/docker_manager/upgrader.rb:81:in `upgrade'
/var/www/discourse/plugins/docker_manager/app/controllers/docker_manager/admin_controller.rb:95:in `block in upgrade'
/var/www/discourse/plugins/docker_manager/app/controllers/docker_manager/admin_controller.rb:91:in `fork'
/var/www/discourse/plugins/docker_manager/app/controllers/docker_manager/admin_controller.rb:91:in `upgrade'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/abstract_controller/base.rb:196:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_controller/metal/rendering.rb:30:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/abstract_controller/callbacks.rb:42:in `block in process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.1/lib/active_support/callbacks.rb:135:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/abstract_controller/callbacks.rb:41:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_controller/metal/rescue.rb:22:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_controller/metal/instrumentation.rb:33:in `block in process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.1/lib/active_support/notifications.rb:180:in `block in instrument'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.1/lib/active_support/notifications/instrumenter.rb:24:in `instrument'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.1/lib/active_support/notifications.rb:180:in `instrument'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_controller/metal/instrumentation.rb:32:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_controller/metal/params_wrapper.rb:245:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.1/lib/active_record/railties/controller_runtime.rb:27:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/abstract_controller/base.rb:136:in `process'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionview-6.0.1/lib/action_view/rendering.rb:39:in `process'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-mini-profiler-1.1.6/lib/mini_profiler/profiling_methods.rb:78:in `block in profile_method'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_controller/metal.rb:191:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_controller/metal.rb:252:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/routing/route_set.rb:51:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/routing/route_set.rb:33:in `serve'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/routing/mapper.rb:18:in `block in <class:Constraints>'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/routing/mapper.rb:48:in `serve'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/journey/router.rb:49:in `block in serve'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/journey/router.rb:32:in `each'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/journey/router.rb:32:in `serve'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/routing/route_set.rb:837:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.1/lib/rails/engine.rb:526:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.1/lib/rails/railtie.rb:190:in `public_send'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.1/lib/rails/railtie.rb:190:in `method_missing'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/routing/mapper.rb:19:in `block in <class:Constraints>'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/routing/mapper.rb:48:in `serve'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/journey/router.rb:49:in `block in serve'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/journey/router.rb:32:in `each'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/journey/router.rb:32:in `serve'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/routing/route_set.rb:837:in `call'
/var/www/discourse/lib/middleware/omniauth_bypass_middleware.rb:68:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.8/lib/rack/tempfile_reaper.rb:15:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.8/lib/rack/conditional_get.rb:38:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.8/lib/rack/head.rb:12:in `call'
/var/www/discourse/lib/content_security_policy/middleware.rb:12:in `call'
/var/www/discourse/lib/middleware/anonymous_cache.rb:318:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.8/lib/rack/session/abstract/id.rb:259:in `context'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.8/lib/rack/session/abstract/id.rb:253:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/middleware/cookies.rb:648:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/middleware/callbacks.rb:27:in `block in call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.1/lib/active_support/callbacks.rb:101:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/middleware/callbacks.rb:26:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/middleware/actionable_exceptions.rb:17:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/middleware/debug_exceptions.rb:32:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/middleware/show_exceptions.rb:33:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/logster-2.7.1/lib/logster/middleware/reporter.rb:43:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.1/lib/rails/rack/logger.rb:38:in `call_app'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.1/lib/rails/rack/logger.rb:28:in `call'
/var/www/discourse/config/initializers/100-quiet_logger.rb:18:in `call'
/var/www/discourse/config/initializers/100-silence_logger.rb:31:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/middleware/remote_ip.rb:81:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/middleware/request_id.rb:27:in `call'
/var/www/discourse/lib/middleware/enforce_hostname.rb:17:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.8/lib/rack/method_override.rb:22:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/middleware/executor.rb:14:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.8/lib/rack/sendfile.rb:111:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.1/lib/action_dispatch/middleware/host_authorization.rb:77:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-mini-profiler-1.1.6/lib/mini_profiler/profiler.rb:184:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/message_bus-2.2.3/lib/message_bus/rack/middleware.rb:57:in `call'
/var/www/discourse/lib/middleware/request_tracker.rb:181:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.1/lib/rails/engine.rb:526:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.1/lib/rails/railtie.rb:190:in `public_send'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.1/lib/rails/railtie.rb:190:in `method_missing'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.8/lib/rack/urlmap.rb:68:in `block in call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.8/lib/rack/urlmap.rb:53:in `each'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.8/lib/rack/urlmap.rb:53:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.3/lib/unicorn/http_server.rb:605:in `process_client'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.3/lib/unicorn/http_server.rb:700:in `worker_loop'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.3/lib/unicorn/http_server.rb:548:in `spawn_missing_workers'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.3/lib/unicorn/http_server.rb:562:in `maintain_worker_count'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.3/lib/unicorn/http_server.rb:295:in `join'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.3/bin/unicorn:128:in `<top (required)>'
/var/www/discourse/vendor/bundle/ruby/2.6.0/bin/unicorn:23:in `load'
/var/www/discourse/vendor/bundle/ruby/2.6.0/bin/unicorn:23:in `<main>'
Spinning up 2 Unicorn worker(s) that were stopped initially

¿Alguien tiene alguna sugerencia?

(Esta es una instalación estándar en el droplet más pequeño de Digital Ocean.)

¿Puedes intentar una reconstrucción desde la consola

cd /var/discourse
./launcher rebuild app

Gracias. No sé por qué no se me ocurrió antes. La primera vez terminó diciendo que debía ejecutarlo de nuevo para finalizar la actualización. Tras ejecutarlo por segunda vez, el sitio está completamente actualizado.