File a thread out of the box it is in, not the list it was found through

docs/tui.md

@@ -65,8 +65,11 @@ Most of those keep working while you are reading a thread, the way the web app's
 toolbar stays live: `r`, `f`, `v`, `b`, `u`, `i`, `l`, `a`, `d`, `p` and `t` all act on
 the thread on screen rather than on the list behind it. Filing a thread leaves it open in
 the box it landed in, so the next key files it on from there; `t` closes it, because a
-trashed thread is not somewhere you file out of. A thread opened from search results, from
-a bundle, or by its id has no row to file and says so instead.
+trashed thread is not somewhere you file out of. Where you opened the thread from does
+not come into it: a bundle, a contact's threads, a label and a search all work, because
+every thread carries the box it is in and files out of that one rather than out of the
+list you found it through. Filing takes the row out of the list you were reading. Only a
+thread opened by its id has no row behind it, and says so instead.
 
 While writing a new message, reply or forward, Ctrl+T opens the searchable Snippets
 picker. HEY never chooses a default: Enter inserts the selected snippet at the body

internal/mail/posting.go

@@ -15,7 +15,11 @@ import (
 // formatting a time into a string and parsing it back is how a reader east of UTC ends
 // up looking at yesterday's date.
 type Posting struct {
-	ID                    int64
+	ID int64
+	// BoxID is the box this row is in, which HEY serves on every posting. A list can
+	// draw rows from several boxes at once — a search, a label, a contact's threads —
+	// so the box a thread files out of is the row's own rather than the list's.
+	BoxID                 int64
 	TopicID               int64
 	CreatedAt             time.Time
 	Name                  string
@@ -73,6 +77,7 @@ func Postings(postings []generated.Posting) []Posting {
 func NewPosting(posting generated.Posting) Posting {
 	return Posting{
 		ID:                    posting.Id,
+		BoxID:                 posting.BoxId,
 		TopicID:               TopicIDOf(posting),
 		CreatedAt:             posting.CreatedAt,
 		Name:                  terminal.SanitizeLine(posting.Name),

internal/mail/posting_test.go

@@ -12,6 +12,7 @@ func TestNewPostingKeepsWhatARowShows(t *testing.T) {
 
 	posting := NewPosting(generated.Posting{
 		Id:                    4471829,
+		BoxId:                 91,
 		AppUrl:                "https://app.hey.com/topics/501",
 		CreatedAt:             created,
 		Kind:                  "topic",
@@ -35,6 +36,11 @@ func TestNewPostingKeepsWhatARowShows(t *testing.T) {
 	if posting.ID != 4471829 || posting.TopicID != 501 || posting.Name != "Kitchen remodel quote" {
 		t.Errorf("posting = %+v", posting)
 	}
+	// The box is the row's own, not the list's: it is what a thread found through a
+	// search, a label or a contact files out of.
+	if posting.BoxID != 91 {
+		t.Errorf("box = %d, want the box HEY served the row in", posting.BoxID)
+	}
 	// HEY's `bundled` means filed inside a bundle; only kind "bundle" makes a row one.
 	if !posting.Seen || posting.IsBundle || !posting.BubbledUp || !posting.Muted || posting.VisibleEntryCount != 3 {
 		t.Errorf("posting state = %+v", posting)

internal/tui/mail.go

@@ -528,7 +528,7 @@ func (v *mailView) Update(msg tea.Msg) (tea.Cmd, bool) {
 		if opened := v.openedPosting(msg.postingID); opened != nil {
 			v.threadPosting = *opened
 		}
-		v.threadBoxKind = v.actionBoxKind()
+		v.threadBoxKind = v.postingBoxKind(v.threadPosting)
 		v.topicName = msg.title
 		v.entries = msg.entries
 		v.attachments = msg.attachments
@@ -734,6 +734,9 @@ func (v *mailView) Update(msg tea.Msg) (tea.Cmd, bool) {
 				v.postingList.postings[idx].Muted = false
 			}
 		}
+		if msg.effect == postingActionRemove {
+			v.removeFromOverlaidLists(msg.postingID)
+		}
 		// The open thread can file back into the box on screen — out and back while
 		// it stays open — and its row was removed when it first filed away, so the
 		// list re-reads its head to hold what the server now does.
@@ -1960,6 +1963,18 @@ func (v *mailView) removePostingAt(index int) {
 	v.postingList.removeAt(index)
 }
 
+// removeFromOverlaidLists takes a row out of the lists drawn over the box list. Nothing
+// re-reads those — a search's results and a bundle's threads are drawn once when they
+// open — so a row left behind stays on screen offering to file a thread that has
+// already moved.
+func (v *mailView) removeFromOverlaidLists(postingID int64) {
+	for _, list := range []*contentList{&v.searchList, &v.bundleList} {
+		if index := postingIndexIn(list.postings, postingID); index >= 0 {
+			list.removeAt(index)
+		}
+	}
+}
+
 func (v *mailView) moveAttachmentCursor(delta int) {
 	if len(v.attachments) == 0 {
 		return
@@ -2400,8 +2415,13 @@ func (v *mailView) openThreadPicker(key string) tea.Cmd {
 // the thread opened, standing in for a row the list may no longer hold — the
 // automatic mark-seen resorts it under the cover and clamps the cursor away, and a
 // live refresh can drop it off the head page — while the thread stays on screen.
+//
+// Where the thread was opened from does not come into it. Every posting HEY serves
+// carries its own box, so a thread found through a search, a bundle, a contact or a
+// label files out of the box it is actually in rather than out of whatever list is
+// behind it. Only a topic opened by its id has no row, and nothing to file.
 func (v *mailView) fileablePosting() *mail.Posting {
-	if v.searchActive || v.bundleActive || v.threadPosting.ID == 0 {
+	if v.threadPosting.ID == 0 {
 		return nil
 	}
 	return &v.threadPosting
@@ -2412,7 +2432,7 @@ func (v *mailView) handlePostingAction(key string) tea.Cmd {
 	if selected == nil {
 		return nil
 	}
-	return v.postingAction(key, *selected, v.actionBoxKind())
+	return v.postingAction(key, *selected, v.postingBoxKind(*selected))
 }
 
 // actionBoxKind is the box kind a list row files out of, empty over a source that
@@ -2424,6 +2444,30 @@ func (v *mailView) actionBoxKind() string {
 	return ""
 }
 
+// postingBoxKind is the box kind a posting files out of, taken from the posting's own
+// box rather than the list showing it. A search, a label, a collection and a contact's
+// threads all draw rows from several boxes at once, so the list's box says nothing
+// about where any one row lives. Falls back to the list for a row HEY served without
+// a box.
+func (v *mailView) postingBoxKind(p mail.Posting) string {
+	if kind := v.boxKindOf(p.BoxID); kind != "" {
+		return kind
+	}
+	return v.actionBoxKind()
+}
+
+func (v *mailView) boxKindOf(boxID int64) string {
+	if boxID == 0 {
+		return ""
+	}
+	for i := range v.boxes {
+		if v.boxes[i].Kind == mail.KindBox && v.boxes[i].ID == boxID {
+			return v.boxes[i].BoxKind
+		}
+	}
+	return ""
+}
+
 // postingAction runs key's action on p. fromBoxKind is the box kind the posting
 // files out of — the list's own box for a row, the box the open thread lives in
 // for a filing key pressed there — so a move to the box it is already in answers