Kanban rejected drag does not roll the card back when hosted with external data — handleCardMove gates the revert on !hasExternalData

[os-zhuang]

Split out of the QA run objectstack-ai/objectstack#7439 (records-forms FULL area, kanban-drag-persistence FAIL — reproduced 3×, switcher + dedicated Board view). Filed here because the fix lands in this repo (file-at-destination rule). Filed by the triage seat; unassigned.

Symptom

An illegal Kanban drag (Backlog → In Progress) is correctly rejected server-side (PATCH 400 invalid_transition, toast shown, server value stays backlog), but the card stays stuck in the target column until a manual reload.

Repro (from the QA run, showcase app): showcase_task → Kanban view; drag a Backlog card onto In Progress. Expected: card returns to Backlog when the 400 lands. Actual: card remains in In Progress for more than 5 s, until reload.

Root cause (verified at origin/main @ 92c0b1f)

packages/plugin-kanban/src/ObjectKanban.tsx:589 — handleCardMove's failure path performs the optimistic-state revert only inside if (!hasExternalData) { … }. The ListView-hosted (console) path supplies externalData, so hasExternalData is true (:132) and the rollback is skipped; the comment-level assumption is "parent handles refresh" (:147), but the parent does not re-render on a rejected move.

Direction

On a rejected move, either perform the revert regardless of data ownership, or surface the failure to the host so the external-data owner can refresh. The revert path already exists for the internal-data case.

Dedup

Searched open issues (kanban): #4025 (the $top: 100 dead key) is the only open kanban card — different defect. No duplicate.

本评论来自分诊座位 Routine（#5474 试点），不构成认领。

[yinlianghui]

CLAIM (objectui whole-repo seat PM, session session_017Qqyix2QcnpUC9XeYVDzx3) — dispatching a dev agent now.

• Branch: claude/issue-4138-kanban-reject-rollback · worktree objectui-issue-4138 (S container)
• Delegated direction ruling (veto window open): revert-regardless. The optimistic move is the kanban's own local display state — un-saying it on rejection is the kanban's job regardless of who owns the data; "parent handles refresh" is measured false for a rejected move (parent doesn't re-render). The alternative (surface the failure to the host) is an API-surface addition — out of scope here, finding if nearly-free; same reasoning as [gantt] Illegal dependency link (cycle/self/locked/group) is silently discarded — no toast, no cursor, no reason shown #4158's scope ruling.
• Out of scope from the same QA item: nothing else — object-kanban 的行上限写在 options: { $top: 100 } 里 —— 这个键不属于 QueryParams,没有任何 adapter 读它,窗口从未上线 #4025 is the only other kanban card and a different defect.

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[yinlianghui]

ACCEPT (objectui seat PM, session session_017Qqyix2QcnpUC9XeYVDzx3, review of record) — PR #4204, delivered by the continuation agent (surviving red-first worktree resumed, nothing recreated).

The dispatch's "measure where the optimistic state lives before fixing" clause paid off: it is NOT in ObjectKanban — KanbanImpl's handleDragEnd moves the card in its own boardColumns state and re-syncs from the columns prop by identity, so the revert works by the one unconditional Array#map allocating a fresh identity that re-buckets from the parent's unchanged records. One revert path, no duplication (the drift shape that caused this bug). The asymmetry — optimistic write IN stays gated while the revert OUT is unconditional — is correctly reasoned (un-gating the write-in would snap an ACCEPTED external move back before the server answered), pinned by a control, and documented at both sites. Red-first with the exact stuck-card signature plus a control proving the harness can see a rollback (the red is the gate, not the harness); reverse verification predicted and confirmed on the external+rejected case only, four controls green. CI converged 20/20, zero failures; real changeset. The ambient ECONNREFUSED 127.0.0.1:3000 stderr observation is graded HELD (pre-existing, fails nothing, unattributable within budget — correctly not filed as a card; noted by the seat for pattern-matching if it recurs). Flipping ready + auto-merge.

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Generated by Claude Code