spec: resolver-path user-task assignment

[delchev]

The problem

A user task's assignee is a role / candidate-group name or the literal personal (the record owner). The reviewer is very often a person the record itself names — the requester's manager, the customer's account manager, the department's approver — and that has no expression today, even though the notify block already resolves one-hop paths off a record with the same kind of validation. The Planned list has carried it since 1.1.

The shape

- name: approve
  kind: userTask
  args:
    assignee: { path: employee.manager, fallback: manager }
    form: ApproveRequest

The behaviour

• Every segment of path is a to-one relation — the first of the trigger entity, each further one of the previous target — and the walk ends at an entity that declares identity, which is what maps a record to a login.
• A cross-model relation may only be the last segment: a projection carries the target's own properties (so its identity is known) but not its relations, so there is nothing to walk on from there.
• A conforming generator validates every hop when the file is read, so a dangling segment is reported then rather than when the process runs.
• fallback is required and names the candidate group. The walk is resolved when the task is reached, not when the process starts — so a relation an earlier step of the same process set is visible — and when it resolves to nobody (a null hop, a missing record, a blank identity) the task is created unassigned and the fallback group can still claim it. That is what makes the unresolvable case total: a resolver path can never mint a task nobody can see.

Prior art

Hand-written code: a delegate that loads the record, chases the foreign keys and calls the task service to set an assignee — the shape every workflow project rebuilds, with the null-hop case usually left to leave an unclaimable task.

Implementation

Eclipse Dirigible: eclipse-dirigible/dirigible#6738 (closes eclipse-dirigible/dirigible#6716) — parse-time hop validation, a delegate inserted before the task, and the assignee expression plus fallback candidate group on the user task.

Changes here

• versions/1.2.md — the Task assignment section, the scoped-surfaces cross-reference, a DSL index row, and the Planned entry removed.