Kibana on Windows 'New platform optimizer error Error: optimizer unexpectedly completed when in watch mode'

[LeeDr]

Kibana version: master

Elasticsearch version: master

Server OS version: Windows 10

Browser version: n/a

Browser OS version: n/a

Original install method (e.g. download page, yum, from source, etc.): github

Describe the bug: On latest master I can't start node scripts/functional_tests_server.js on Windows 10 (in a gitbash shell). It looks like it's getting really close and then logs;
New platform optimizer error Error: optimizer unexpectedly completed when in watch mode

Steps to reproduce:

1. I'm on master on this commit commit 07c22f1
2. yarn kbn bootstrap
3. node scripts/functional_tests_server.js (from kibana dir)

Expected behavior:

Screenshots (if relevant):

Errors in browser console (if relevant):

Provide logs and/or server output (if relevant):

   │ info [kibana] > node scripts\kibana --no-base-path --env.name=development --optimize.bundleDir=C:\Users\LeeDr\git\kibana\data\optimize\bundles --logging.json=false --server.port=5620 --optimize.watchPort=5630 --op
e.watchPrebuild=true --status.allowAnonymous=true --optimize.enabled=true --elasticsearch.hosts=http://elastic:changeme@localhost:9220 --elasticsearch.username=kibana --elasticsearch.password=changeme --home.disableWel
creen=true --telemetry.banner=false --server.maxPayloadBytes=1679958 --plugin-path=C:\Users\LeeDr\git\kibana\test\common\fixtures\plugins\newsfeed --newsfeed.service.urlRoot=http://localhost:5620 --newsfeed.service.pat
late=/api/_newsfeed-FTS-external-service-simulators/kibana/v{VERSION}.json --oss --telemetry.optIn=false --dev --no-dev-config
   │ proc [kibana]   log   [16:51:38.211] [warning][plugins-discovery] Explicit plugin paths [C:\Users\LeeDr\git\kibana\test\common\fixtures\plugins\newsfeed] should only be used in development. Relative imports may no
k properly in production.
   │ proc [kibana]   log   [16:51:38.230] [warning][plugins-discovery] Expect plugin "id" in camelCase, but found: apm_oss
   │ proc [kibana]   log   [16:51:38.231] [warning][plugins-discovery] Expect plugin "id" in camelCase, but found: dashboard_embeddable_container
   │ proc [kibana]   log   [16:51:38.232] [warning][plugins-discovery] Expect plugin "id" in camelCase, but found: status_page
   │ proc [kibana]   log   [16:51:44.737] [warning][legacy-plugins] Unable to scan directory for plugins "C:\Users\LeeDr\git\kibana\plugins"
   │ proc [kibana]   log   [16:51:47.739] [info][plugins-service] Plugin initialization disabled.
   │ proc [kibana]   log   [16:51:47.745] [info][savedobjects-service] Waiting until all Elasticsearch nodes are compatible with Kibana before starting saved objects migrations...
   │ proc [kibana]   log   [16:51:47.807] [info][savedobjects-service] Starting saved objects migrations
   │ proc [kibana]   log   [16:51:47.844] [info][savedobjects-service] Creating index .kibana_1.
   │ info [o.e.c.m.MetaDataCreateIndexService] [LEEDR-XPS] [.kibana_1] creating index, cause [api], templates [], shards [1]/[1], mappings [_doc]
   │ info [o.e.c.r.a.AllocationService] [LEEDR-XPS] updating number_of_replicas to [0] for indices [.kibana_1]
   │ info [o.e.c.r.a.AllocationService] [LEEDR-XPS] Cluster health status changed from [YELLOW] to [GREEN] (reason: [shards started [[.kibana_1][0]]]).
   │ proc [kibana]   log   [16:51:49.209] [info][savedobjects-service] Pointing alias .kibana to .kibana_1.
   │ proc [kibana]   log   [16:51:49.391] [info][savedobjects-service] Finished in 1558ms.
   │ proc [kibana] np bld    log   [16:51:50.400] [info][@kbn/optimizer] initialized, 0 bundles cached
   │ proc [kibana] np bld    log   [16:51:50.400] [success][@kbn/optimizer] 0 bundles compiled successfully after 0.3 sec, watching for changes
   │ proc [kibana]  New platform optimizer error  Error: optimizer unexpectedly completed when in watch mode
   │ proc [kibana]     at Object.complete (C:\Users\LeeDr\git\kibana\packages\kbn-optimizer\src\optimizer\handle_optimizer_completion.ts:40:19)
   │ proc [kibana]     at TapSubscriber._complete (C:\Users\LeeDr\git\kibana\node_modules\rxjs\src\internal\operators\tap.ts:140:25)
   │ proc [kibana]     at TapSubscriber.Subscriber.complete (C:\Users\LeeDr\git\kibana\node_modules\rxjs\src\internal\Subscriber.ts:126:12)
   │ proc [kibana]     at MergeMapSubscriber.notifyComplete (C:\Users\LeeDr\git\kibana\node_modules\rxjs\src\internal\operators\mergeMap.ts:172:24)
   │ proc [kibana]     at InnerSubscriber._complete (C:\Users\LeeDr\git\kibana\node_modules\rxjs\src\internal\InnerSubscriber.ts:26:17)
   │ proc [kibana]     at InnerSubscriber.complete (C:\Users\LeeDr\git\kibana\node_modules\rxjs\src\internal\Subscriber.ts:126:12)
   │ proc [kibana]     at SafeSubscriber.subscriber.add.event$.subscribe [as _complete] (C:\Users\LeeDr\git\kibana\packages\kbn-optimizer\src\common\event_stream_helpers.ts:102:24)
   │ proc [kibana]     at SafeSubscriber.wrappedComplete (C:\Users\LeeDr\git\kibana\node_modules\rxjs\src\internal\Subscriber.ts:248:54)
   │ proc [kibana]     at SafeSubscriber.__tryOrUnsub (C:\Users\LeeDr\git\kibana\node_modules\rxjs\src\internal\Subscriber.ts:265:10)
   │ proc [kibana]     at SafeSubscriber.complete (C:\Users\LeeDr\git\kibana\node_modules\rxjs\src\internal\Subscriber.ts:251:16)
   │ proc [kibana]     at Subscriber._complete (C:\Users\LeeDr\git\kibana\node_modules\rxjs\src\internal\Subscriber.ts:148:22)
   │ proc [kibana]     at Subscriber.complete (C:\Users\LeeDr\git\kibana\node_modules\rxjs\src\internal\Subscriber.ts:126:12)
   │ proc [kibana]     at MergeMapSubscriber.notifyComplete (C:\Users\LeeDr\git\kibana\node_modules\rxjs\src\internal\operators\mergeMap.ts:172:24)
   │ proc [kibana]     at InnerSubscriber._complete (C:\Users\LeeDr\git\kibana\node_modules\rxjs\src\internal\InnerSubscriber.ts:26:17)
   │ proc [kibana]     at InnerSubscriber.Subscriber.complete (C:\Users\LeeDr\git\kibana\node_modules\rxjs\src\internal\Subscriber.ts:126:12)
   │ proc [kibana]     at MergeMapSubscriber._complete (C:\Users\LeeDr\git\kibana\node_modules\rxjs\src\internal\operators\mergeMap.ts:154:24)
   │ info [kibana] exited with null after a few seconds

Command failed: taskkill /pid 2712 /T /F
ERROR: The process "2712" not found.

ERROR: The process "2712" not found.

    at ChildProcess.exithandler (child_process.js:294:12)
    at ChildProcess.emit (events.js:198:13)
    at maybeClose (internal/child_process.js:982:16)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:259:5)

Any additional context:
That last error about failing to kill 2712 is also a recent new problem. I think it's trying to kill the Elasticsearch java process, but it's still running. The PID in this particular instance is 2516, not 2712.

[elasticmachine]

Pinging @elastic/kibana-operations (Team:Operations)

[LeeDr]

I tried starting functional_tests_servers from the x-pack dir and it failed the same way.

I tried yarn start from Kibana directory and that appears to work but I didn't have Elasticsearch running so it just releases No living connections