Module interchange

Expand description

Interchangeable parts (feature 6, see docs/src/research/supersede-alternates.md):

Alternates – item B may be built in instead of item A in every assembly (item_alternates, one row per direction; “two-way” stores both). Item-level, not revisioned.
Supersession – item A is superseded by B: do not use A for new designs any more (item_supersessions, at most one successor, no chain back to A). The lifecycle state of A does not change.
Replace in assemblies – a mass change on the where-used list of A: every assembly whose latest revision is in work and not checked out by somebody else gets B instead of A (quantity, find number and notes kept); released assemblies and assemblies in review are listed as needing a new revision. plan_replace is the preview, replace applies exactly the same plan under row locks.

Items in groups the actor may not read are left out (and counted where a list is about usages of the actor’s item).

Structs§

LinkedItem: An item linked to another one as alternate, successor or predecessor, with the data of its latest revision.
NewAlternate
ReplacePlan: The preview (or, after replace, the outcome) of a replacement.
ReplaceRow: One BOM line of the latest revision of an assembly that uses the item.

add_alternate: Declares input.number an alternate of item_id.
alternate_for: Items for which item_id is a one-way alternate (the two-way ones are already in alternates).
alternates: Items that may be used instead of item_id (only those the actor may read).
clear_supersession: Withdraws the supersession of item_id.
plan_replace: Preview: what replace would do with every assembly using old_item_id.
predecessors: Items that item_id supersedes (only those the actor may read).
remove_alternate: Removes the alternate alternate_item_id of item_id – both directions when the actor may also edit the alternate’s group, otherwise only this one. Returns the number of directions removed.
replace: Replaces old_item_id by new_number in every assembly the plan marks ReplaceAction::Replace, in one transaction. A revision that is not checked out is changed directly (like check out, edit, check in); one checked out by the actor stays checked out. Fails when nothing can be replaced.
successor: The item that supersedes item_id; a successor in a group the actor may not read is a placeholder (the item is still superseded).
supersede: Declares item_id superseded by successor_number (replacing an earlier successor).
superseded_among: Which of the given items are superseded: item id → number of the successor (None when the successor is in a group the actor may not read). For marking BOM lines.