Update Deprecation Info API for 7.0 breaking changes

[gwbrown]

The Deprecation Info API should be updated to check for breaking changes coming in the next major version.

Here is a list created by looking through the breaking changes list in the docs and >breaking PRs. I have not verified each one of these, it will likely be necessary to add and/or remove items from this list.

Cluster

• : is no longer allowed in the cluster name (change in Disallow : in cluster and index/alias names #26247) Deprecation check for : in Cluster/Index name #36185
• [] Shard preferences _primary, _primary_first, _replica, and _replica_first are removed (change in Should search preference _primary take primary relocation target into account? #26335)
  [^^ This is a query-time parameter]
• Cluster-wide shard soft limit (change in Always enforce cluster-wide shard limit #34892)
• Renamed no-master-block setting (changes in Rename no-master-block setting #38350) Deprecation check for No Master Block setting #38383

Indices

• Check for multiple types in indices created in 5.x, as this prevents automatic reindexing (see Implementation tracking for 7.0 types deprecation. #35190) Deprecation check for indices with multiple types #36952
• [] standard token filter removal (does this need a check?) (change in Upgrade to a Lucene 8 snapshot #33310)
  [^^ this does not need a check, as it is special-cased in 7.0 for indices created in 6.x and this token filter is a no-op anyway]
• delimited_payload_filter renamed (changes in Remove delimited_payload_filter #27705) Remove delimited_payload_filter and add to migration assistant #27704
• : is no longer allowed in index name (change in Disallow : in cluster and index/alias names #26247) Deprecation check for : in Cluster/Index name #36185
• index.unassigned.node_left.delayed_timeout may no longer be negative (change in Forbid negative values for index.unassigned.node_left.delayed_timeout #26828) (deprecation info API: negative index.unassigned.node_left.delayed_timeout #36454)
• fix value for index.shard.check_on_startup is removed (change in completely drop index.shard.check_on_startup: fix for 7.0 #33194) (deprecation info API: 'fix' value for index.shard.check_on_startup #36458)
• [] index_options for numeric fields has been removed (change in Reject the index_options parameter for numeric fields #26668)
  [^^ this does not need a check as indices with `index_options` on numeric fields behave fine in 7.0 if they existed prior to upgrade]
• [] Limiting the number of nested json objects (?) (change in Limit the number of nested documents #27405)
  [^^ can't check this without running a query]
• The classic similarity has been removed (change in Improve similarity integration. #29187) Deprecation check for classic similarity #36577
• [] Similarities fail when unsupported options are provided (change in Improve similarity integration. #29187)
  [^^ this does not need a check as indices with unsupported similarity options behave fine in 7.0 if they existed prior to upgrade]
• Deprecated index.percolator.map_unmapped_fields_as_string setting has been removed (changes in remove deprecated percolator map_unmapped_fields_as_string setting #28060) Deprecation check for percolator.map_unmapped_fields_as_string #36460

Nodes

• Azure Repository plugin settings changes
• Google Cloud Storage Repository plugin settings changes
• File-based discovery plugin removed and path changed (changes in Remove discovery-file plugin #33257) Deprecation check for File Discovery plugin #36190
• [] The default for node.name is now the hostname (changes in Core: Default node.name to the hostname #33677)
  [^^ There doesn't appear to be a way to check this one]
• Tribe node has been removed (changes in Remove tribe node support #28443) Deprecation check for tribe node #36240
• Http enabled setting removed (changes in Network: Remove http.enabled setting #29601) Deprecation check for http.enabled setting #36394
• Settings thread_pool.index.size and thread_pool.index.queue_size have been removed (changes in Remove the index thread pool #29556) Deprecation check for index threadpool #36520
• Http pipelining setting removed (changes in Make http pipelining support mandatory #30695) Deprecation check for HTTP pipelining #36521
• Audit logfile local node info settings removed (changes in Logfile auditing settings remove after deprecation  #35205) Deprecation check for audit log prefix settings #36661
• Write threadpool fallback removed (changes in Remove bulk fallback for write thread pool #29609) Deprecation check for renamed bulk threadpool settings #36662
• Security realms type setting removed (changes in Include realm type in Security Realm setting keys #30241) Deprecation check for Auth realm setting structure #36664
• Discovery configuration is required in production (changes in [Zen2] Best-effort cluster formation if unconfigured #36215) Deprecation check for discovery configuration #36666
• Watcher Notifications Account "unsecure" settings removed (changes in Remove Watcher Account "unsecure" settings #36736 and Watcher deprecate notification service settings #36403) Watcher notification settings Upgrade checks #36907
• SSL setting fallback removed (Changes in Security: remove SSL settings fallback #36846) Add deprecation warnings for ssl config fallback #36847
• TLS 1.0 removed from default protocols list (Changes in Remove TLS 1.0 as a default SSL protocol #37512) Add TLS version changes to deprecation checks #37793
• User-Agent ingest plugin alignment with ECS (changes in Add ECS schema for user-agent ingest processor #37727) Dep. check for ECS changes to User Agent processor #38362
• Security is no longer implicitly enabled on trial licenses Deprecate implicit security on trial licenses #38295

[elasticmachine]

Pinging @elastic/es-core-features

[joshdover]

@gwbrown Will you be updating the Migration Assistance API as part of this as well or is that separate?

As it stands right now, I'm not sure we need this API going forward. Since the Deprecation Info API provides information about indexes that need to be reindexed and as far as I know, there won't be any internal indices requiring upgrade through the Migration Upgrade API in the 7.0 upgrade, it seems like maybe we should remove this two APIs completely?

Whether or not we remove them, I will need to know whether or not we anticipate any useful data coming from these in 6.7 or not. If not, I'd like to drop our usage of them completely in Kibana to simplify things quite a bit.

[gwbrown]

@joshdover I've created #36514 to track and discuss those APIs ES-side. I don't believe we should get rid of them completely, as especially the Migration Upgrade API is highly likely to be necessary for a future major version, even if it isn't for this one.

We may be able to drop their usage from Kibana however, depending on what folks familiar with Watcher and Security have to say.

[gwbrown]

All items on the checklist above are complete, but I'm going to leave this issue open for another day or two just in case, even though I believe we're past the point of adding more. I'll continue to monitor for any new breaking changes and close this in a few days if nothing comes up.

[gwbrown]

Closing this as nothing else has come up.