dotted multi entity

Q Do dotted paths through a multi-entity field work, for reads and for filters?

Endpoint GET /entity/shots?fields=code,sg_sequence.Sequence.code,tasks.Task.content,assets.Asset.code ; POST /entity/shots/_search

Docs claim Dotted paths are documented for ?fields and for filters; the docs say nothing about multi-entity fields behaving differently from single-entity ones.

Actual

data types: {"sg_sequence": "entity", "tasks": "multi_entity", "assets": "multi_entity"}

=== READ: dotted in ?fields
  attributes returned: ['code', 'sg_sequence.Sequence.code']
  -> single-entity (sg_sequence) present; multi-entity (tasks, assets) silently absent

=== FILTER: dotted through multi-entity (baseline 300 shots)
  negative controls — must be 0 if the filter is real:
    tasks.Task.content is ZZZNOPE                      -> 0
    assets.Asset.code is ZZZNOPE                       -> 0
    assets.Asset.sg_asset_type is ZZZNOPE (two hops)   -> 0
  positives:
    tasks.Task.content is Comp                         -> 300
    assets.Asset.sg_asset_type is Character            -> 284
    tasks is {type,id}                                 -> 1

=== page size
  asked 500 -> 300 (all)   asked 150 -> 150   asked 50 -> 50

=== FILTER: Note.note_links, whose valid_types is 28 types on the probed site (probe 071)
  one _summarize record_count per type, over 5944 Notes in the sample project
    note_links.<Type>.cached_display_name contains 'bunn'   200 on 28 of 28
    note_links.<Type>.code                contains 'bunn'   200 on 27, 400 on Booking
    note_links.<Type>.name                contains 'bunn'   200 on 1 (Department), 400 on 27
  400 "API summarize() Note.note_links.Booking.code doesn't exist."  same body for .Group.name
      and for .ZzNotAType.code; the bare field, note_links contains, 400s "'multi_entity' data
      type doesn't support 'contains' 'relation'"
  note_links.Shot.code contains 'ZZZNOPE' 0 ; is 'sh010' 20 ; cached_display_name is 'sh010' 20
  note_links.Shot.sg_sequence.Sequence.code is_not null 5944 (two hops)
  ?fields=subject,note_links.Shot.code -> 200, attributes ['subject']

Teaches

• Trap. The read failure is silent and indistinguishable from "no data": the key is not in attributes, the same quiet drop a bogus ?fields name gets (probe 004). Single-entity paths like sg_sequence.Sequence.code come back fine, so the difference is the field's data_type, not the syntax.
• The filters are evaluated, not ignored: every negative control returns 0, and two hops (assets.Asset.sg_asset_type) resolve. On the probed site the positives return partial counts, 284 of 300.
• Filter through multi-entity freely. To read those values, query the child entity separately (/entity/tasks filtered by the parent) rather than asking for them inline.
• Name the target type and a field that type has. A path is validated against the named type, not against the link's valid_types, so note_links.Booking.code and note_links.Group.name both 400 doesn't exist while both types are legal targets. cached_display_name is the one name field every type answers to, and it is what a "notes about X" search should use (probe 071).
• Corrects probe 005: page[size] is not capped at 100. On the probed site 150 returned 150 rows and 500 returned all 300.