[Juliusolsson05]

Fixes #1379. Depends on #1374 (merged into this branch; merge #1374 first). Keeping the pointer only helps if restoring the parent relinks it, and that relink is #1374's.

Plan: docs/plans/2026-09-27-replace-keeps-closed-parent-pointer.md (first commit).

Problem

Replace (reload, provider switch, resume, rewind) and Reload Agents commit through remapSessionsRelationships(sessions, idMap). That drops any linkedParentId / orchestrationParentId / orchestrationRootId whose target is neither live nor in the idMap. A parent that is closed but still on the undo stack is neither. So reloading its live child erased the child's link, and undoing the parent later (#1374's relink) found nothing to relink: two live panes, permanently unlinked. Found by review c of #1374.

What merges

• UndoCloseStack.restorableSessionIds(): every session id a waiting entry could bring back (session, project and group members). It is pruned first, like pop(), so an expired entry never counts.
• Both commits (replace, Reload Agents) pass knownSessionIds = live ids ∪ restorable ids, through knownOrRestorable.
• Unchanged: a pointer to a parent nothing can bring back (deleted, or its undo entry expired) is still dropped at the swap.
• Kept pointers do not outlive the chance of a restore (review a). When the parent's entry leaves the stack WITHOUT being restored, dropPointersTo drops live pointers to exactly those ids, and never touches unrelated or cross-window pointers. That covers an entry consumed as stale or failed, one that expired, and one evicted past the cap. The stack reports expiry and eviction on a microtask, because prune can run inside a setState updater.

Tests

• closedParentPointer.renderer.test.tsx:
  • a child replaced, and a child reloaded by Reload Agents, while its parent sits on the undo stack keeps all three pointers; both were red on main;
  • the control: a gone parent's pointers are still dropped.
• lib/undoClose.test.ts: restorableSessionIds over session, tab and group entries, with expiry.
• Group replay (undoCloseGhostPointers.renderer.test.tsx): a child restored after its parent was consumed, and a leftover pushed back for retry, both drop the dead pointer. An expiry notification reaches the workspace.
• End to end (with fix(undo-close): a restored parent's live children follow it to its new id #1374): close P, reload its live child, undo P, and the child names P′. Red without fix(undo-close): a restored parent's live children follow it to its new id #1374's remap.
• Ghost pointers: a consumed-as-stale parent entry drops the kept pointers. dropPointersTo and the stack's expiry and eviction notifications have unit tests.
• Red checks: un-wiring either call site fails its test, and so does removing the consumed-entry drop, either notification, or the liveness guard.
• sessionRecovery.renderer.test.tsx: one hand-built refs mock now carries undoStackRef. Production refs always do.
• Gates: on 02e03d92, npx tsc -b is clean, and src/renderer/src/workspace/hook + src/renderer/src/lib pass (72 files, 476 tests).

Related

• fix(undo-close): a restored parent's live children follow it to its new id #1374 relinks a restored parent's live children. This PR keeps the link alive when the child was reloaded meanwhile. Merge fix(undo-close): a restored parent's live children follow it to its new id #1374 first.

🤖 Generated with Claude Code

[Juliusolsson05]

Review disposition (head 02e03d92).

• Round 1: a and b FIX-BEFORE-MERGE (the same major); c (pi) MERGE-READY with one minor.
• Round 2: a FIX-BEFORE-MERGE (one new minor); b MERGE-READY.
• Round 3: a FIX-BEFORE-MERGE (one more minor).
• Round 4: a MERGE-READY.

Fixed

• a + b (major): the kept pointer did not reconnect after Undo Close on its own. This PR now depends on fix(undo-close): a restored parent's live children follow it to its new id #1374, which is merged into this branch; merge fix(undo-close): a restored parent's live children follow it to its new id #1374 first. An end-to-end test closes P, reloads its live child, undoes P and asserts the child names P′. It is red without fix(undo-close): a restored parent's live children follow it to its new id #1374's remap.
• a r1 / c (minor): the kept pointer lingered after P's entry left the stack unrestored, as a ghost that still classified the child as an orchestration worker. dropPointersTo drops pointers to exactly those ids, and never unrelated or cross-window ones, when:
  • an entry is consumed as stale or failed;
  • an entry expires or is evicted (the stack notifies on a microtask, because prune runs inside a setState updater).
• b r2 (minor): the expiry → workspace wiring was untested. A hook-level test now makes removing the listener red.
• a r2 (minor): a group replays newest-first, so a child restored after its parent was consumed carried the dead pointer back. The group now drops pointers to the members it consumed once it has replayed.
• a r3 (minor): a leftover pushed back for retry still named the consumed parent, so the retry restored it. Its metadata is now cleaned before the push (dropEntryPointersTo).

Every fix was red before it landed, on the reviewer's own sequence. Each guard was removed on its own, and each removal fails a test.

Merge order: #1369, then #1374, then this PR.

🤖 Generated with Claude Code