@cc [owner:Yassimba] connection.typed-offline-resolution
Applies only to `ConnectionOpener.resolve` in `datasources/connections.py`.

resolve returns the Datasource's original validated connection config without importing a database driver or starting authentication.
Driver availability is not a prerequisite for resolving an otherwise valid config.
@cc [owner:Yassimba] datasource.connection-pair
Applies only to `DatasourceConnection` in `datasources/connections.py`.

A valid DatasourceConnection directly contains both its selected declaration and its typed authored document.
It has no independent missing-member state or BoundConnection wrapper.

@cc [owner:Yassimba] datasource.profile-identity
Applies only to `Datasource` in `formats/datasource/datasource.py`.

Shared connection fields and named profiles belong to one Datasource document and one Datasource identity.
Selecting a profile can change connection fields but cannot rewrite a Datasource name, Server, or Product Key.

@cc [owner:Yassimba] datasource.authored-trusted-boundary
Applies only to `Datasource.require_resolved` in `formats/datasource/datasource.py`.

Invalid or incomplete authored content remains available for editor recovery without becoming trusted
runtime facts. Producing a OpenableDatasource requires valid datasource identities, connection authoring
state, connection timeout, and time zone.

@cc [owner:Yassimba] datasource.declaration-derived-authoring
Applies only to `envelope_model` in `formats/datasource/datasource_types.py`.

An extension's single ConnectionModel declaration supplies shared-field and profile-field authoring support.
Both locations preserve declared types, nullability, constraints, aliases, descriptions, secret rules,
environment guidance, and local-path metadata. Omission is permitted in field-presence views without making
supplied values more permissive or inserting runtime defaults.

@cc [owner:Yassimba] datasource.profile-selection
Applies only to `OpenableDatasource.config` in `datasources/connections.py`.

An absent or empty profiles mapping uses the fixed connection regardless of invocation selection.
Otherwise, an explicit invocation selection must match a profile exactly; it never falls back to the default.
Without an invocation selection, use defaultProfile or refuse if it is absent.
A refusal lists available names and requests a selection when none was supplied.

@cc [owner:Yassimba] datasource.field-combination
Applies only to `OpenableDatasource.config` in `datasources/connections.py`.

Combine only supplied shared and selected-profile fields by canonical field identity, honoring accepted
aliases. A supplied profile value replaces the whole shared field; omission inherits it.
Null, false, zero, and empty strings are supplied values, with validity determined by the original field type.
Nested objects, mappings, and lists replace the complete field instead of merging recursively.

@cc [owner:Yassimba] datasource.effective-inputs
Applies only to `OpenableDatasource.config` in `datasources/connections.py`.

Resolve environment references only in the effective field set using the explicitly supplied environment.
Inactive profiles and overridden shared references do not require environment values.
A missing selected reference causes a refusal; LocalPath values follow the existing base-directory rule.
The original extension model validates the complete effective config and applies its runtime defaults
after resolution.

@cc [owner:Yassimba] datasource.immutable-inputs
Applies only to `OpenableDatasource.config` in `datasources/connections.py`.

Resolution leaves authored values, the source document, the Project Snapshot, and cached model definitions
unchanged. Resolved credentials are not retained in a Project Snapshot or a process-global config cache.

@cc [owner:Yassimba,test:test_datasource_origin_capability_at_snapshot_seam_points_to_shared_and_profile_fields] datasource.source-locations
Applies only to `OpenableDatasource.config` in `datasources/connections.py`.

An effective-field error identifies the authored source of the winning value through existing source
pointers and DatasourceOrigin. Inherited values point to shared fields; overrides point to fields under
their selected profile. Missing effective fields point to the relevant connection or profile location.
Cross-field errors identify the effective profile and include related positions where the diagnostic
model supports them.

@cc [owner:Yassimba] flagged-scan.engine-scope-free
Applies only to `FlagInputs` and `CheckEngine.flag_rows` in `check_types/engine.py`.

An engine gives only its unflagged one-scan statement and one failing-row predicate per failed-rows check,
or the results and the verdicts of its own rows scan.
It never reads, builds, or stores a Row Key, and never receives a Flag Scope, a grouping set, or a Scratch Table.

@cc [owner:Yassimba,test:test_connection_match_decision_table_at_engine_seam_refuses_a_session_without_the_protocol] check-engine.connection-match
Applies only to `implements` in `datasources/connections.py`.

An engine runs on a Datasource only when its session class defines every member of the engine's `requires` Protocol.
No registration step changes the match.

@cc [owner:Yassimba,test:test_schema_inspection_decision_at_connection_seam_gives_not_supported_for_a_plain_session] schema.inspect-on-connection
Applies only to `inspect_schema` in `check_types/schema_validation.py`.

`inspect_schema` gives not supported for a connection that is not `DescribesTables`.
It never raises for that case.

@cc [owner:Yassimba,test:test_body_lint_decision_table_at_sql_engine_seam_reports_only_a_parse_refusal] check-type.placeholder-needs-each-required-value
Applies only to `CheckType.placeholder_checks` in `check_types/check_type.py`.

A Check Type with a required argument whose type has no placeholder value gives no placeholder
check, so no engine tries its body with a value that can be wrong.

@cc [owner:Yassimba,test:test_untyped_argument_decision_table_at_render_seam_keeps_the_kind_of_each_plain_value] check-type.undeclared-argument-is-any
Applies only to `CheckType.assemble` in `check_types/check_type.py`.

An argument that the body reads and the front matter does not declare is required and has the
type `any`: it accepts text, a number, or true or false, and refuses a list and an object.

@cc [owner:Yassimba,test:test_lookback_refusal_decision_table] check-type.lookback-fits-type
Applies only to `CheckType` in `check_types/check_type.py`.

A `lookback` is a duration longer than zero or a whole number of rows above zero, for example
`3d` or `30 rows`. A Check Type whose front matter has `lookback: true` refuses a check with no
`lookback`. Each other Check Type refuses a check that has one. A Check Type refuses `groupBy`
when it has no `lookback` and its engine cannot measure each group of rows. Each refusal says
what to write.
