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CPLAT-12558: move the heavy session previews off the UI loop #174

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Merged
gavin-jeong merged 1 commit into from
Oct 2, 2026
Merged

CPLAT-12558: move the heavy session previews off the UI loop #174

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163 changes: 113 additions & 50 deletions internal/tui/app.go
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Original file line number Diff line number Diff line change
Expand Up @@ -240,6 +240,21 @@ type App struct {
sessionList list.Model
sessionRowCache *sessionRowCache
convPreviewRowCache *sessionRowCache
// Collected outputs survive a row change so walking the list up and down
// does not rescan the same transcripts (see outputsStore).
sessOutputsStore *outputsStore

// Preview payloads loaded off the UI loop, keyed by mode+session+mtime.
// previewLoadInFlight dedups a load that a repeated row visit would
// otherwise dispatch twice before the first one lands.
previewLoads *sessionStore[any]
previewLoadInFlight map[string]bool

// Per-mode payloads the renderers read, filled by applyPreviewLoad.
sessCtxTree *session.SessionContextTree
sessCtxErr error
sessScratchpadFiles []session.ScratchpadFile
sessShellJobs []session.ShellJob

// Split panes
sessSplit SplitPane
Expand Down Expand Up @@ -963,6 +978,8 @@ func NewApp(sessions []session.Session, cfg Config) *App {
notifyPrev: make(map[string]session.LifecycleState),
sessionRowCache: newSessionRowCache(1024),
convPreviewRowCache: newSessionRowCache(4096),
sessOutputsStore: newOutputsStore(outputsStoreCap),
previewLoads: newSessionStore[any](previewStoreCap),
termFocused: true,
// Default to a true project-centric browser: ccx now opens with one
// row per project (folder-like), and sessions of the same repo (and
Expand Down Expand Up @@ -1258,6 +1275,9 @@ func (a *App) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
}
return a, nil

case previewLoadMsg:
return a, a.handlePreviewLoad(msg)

case previewDebounceMsg:
if msg.id != a.previewDebounceID {
return a, nil // stale: a newer navigation happened
Expand Down Expand Up @@ -1516,6 +1536,9 @@ func (a *App) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
// different session — the digest state tracks exactly one session, and
// adopting a stale result would show another session's outputs.
delete(a.outputsInFlight, msg.id)
// Keep the result even when the cursor has moved on: the scan already
// happened, and storing it is what makes moving back free.
a.sessOutputsStore.Set(msg.dataKey, msg.outputs)
if a.sessOutputsCacheID != msg.id {
return a, nil
}
Expand Down Expand Up @@ -5392,7 +5415,8 @@ func previewDispatchesCmd(mode sessPreview) bool {
// through to the project-summary preview rather than being re-routed to a
// representative session — so the two predicates are deliberately not merged.
func previewDispatchesFromView(mode sessPreview) bool {
return previewDispatchesCmd(mode) || mode == sessPreviewConversation
return previewDispatchesCmd(mode) || mode == sessPreviewConversation ||
previewLoadsOffLoop(mode)
}

func (a *App) renderSessionSplit() string {
Expand Down Expand Up @@ -5671,17 +5695,17 @@ func (a *App) updateSessionPreviewWith(dispatch bool) tea.Cmd {
case sessPreviewMemory:
a.updateSessionMemoryPreview(sess)
case sessPreviewScratchpad:
a.updateSessionScratchpadPreview(sess)
return a.updateSessionScratchpadPreview(sess)
case sessPreviewTasksPlan:
a.updateSessionTasksPlanPreview(sess)
case sessPreviewAgents:
a.updateSessionAgentsPreview(sess)
return a.updateSessionAgentsPreview(sess)
case sessPreviewWorkflows:
a.updateSessionWorkflowsPreview(sess)
return a.updateSessionWorkflowsPreview(sess)
case sessPreviewShells:
a.updateSessionShellsPreview(sess)
return a.updateSessionShellsPreview(sess)
case sessPreviewContexts:
a.updateSessionContextsPreview(sess)
return a.updateSessionContextsPreview(sess)
case sessPreviewRefs:
return a.updateSessionRefsPreview(sess)
case sessPreviewOutputs:
Expand Down Expand Up @@ -6436,16 +6460,27 @@ func (a *App) updateSessionMemoryPreview(sess session.Session) {
a.sessSplit.Preview.SetContent(a.sessMemoryCache)
}

func (a *App) updateSessionScratchpadPreview(sess session.Session) {
func (a *App) updateSessionScratchpadPreview(sess session.Session) tea.Cmd {
if a.sessScratchpadCacheKey != sess.ID {
a.sessScratchpadCache = a.buildScratchpadContent(sess)
a.sessScratchpadCacheKey = sess.ID
a.sessScratchpadFiles = nil
a.sessScratchpadCache = ""
a.sessScratchpadCacheKey = ""
}
cmd := a.adoptPreviewLoad(sessPreviewScratchpad, sess)
if a.sessScratchpadCacheKey != sess.ID {
if _, loaded := a.previewLoads.Get(previewLoadKey(sessPreviewScratchpad, sess)); loaded {
a.sessScratchpadCache = a.buildScratchpadContent(sess, a.sessScratchpadFiles)
a.sessScratchpadCacheKey = sess.ID
} else {
a.sessScratchpadCache = dimStyle.Render("(loading scratchpad…)")
}
}

previewW := max(a.width-a.sessSplit.ListWidth(a.width, a.splitRatio)-1, 1)
contentH := max(a.height-3, 1)
a.sessSplit.Preview = viewport.New(previewW, contentH)
a.sessSplit.Preview.SetContent(a.sessScratchpadCache)
return cmd
}

func (a *App) updateSessionTasksPlanPreview(sess session.Session) {
Expand All @@ -6460,27 +6495,39 @@ func (a *App) updateSessionTasksPlanPreview(sess session.Session) {
a.sessSplit.Preview.SetContent(a.sessTasksCache)
}

func (a *App) updateSessionAgentsPreview(sess session.Session) {
func (a *App) updateSessionAgentsPreview(sess session.Session) tea.Cmd {
cmd := a.adoptPreviewLoad(sessPreviewAgents, sess)
previewW := max(a.width-a.sessSplit.ListWidth(a.width, a.splitRatio)-1, 1)
contentH := max(a.height-3, 1)
a.sessSplit.Preview = viewport.New(previewW, contentH)
if _, loaded := a.previewLoads.Get(previewLoadKey(sessPreviewAgents, sess)); !loaded {
a.sessSplit.Preview.SetContent(dimStyle.Render("(loading agents…)"))
return cmd
}
a.sessSplit.Preview.SetContent(a.buildAgentsPreviewContent(sess))
return cmd
}

func (a *App) updateSessionWorkflowsPreview(sess session.Session) {
// Load + join workflow runs and their nested agents once per session, so the
// cursor can drill into any agent's transcript.
// updateSessionWorkflowsPreview renders the workflow runs for a session. The
// runs and their nested agents are loaded off the UI loop once per session, so
// the cursor can drill into any agent's transcript without re-reading it.
func (a *App) updateSessionWorkflowsPreview(sess session.Session) tea.Cmd {
if a.sessWorkflowsCacheKey != sess.ID {
a.sessWfRuns, _ = session.FindWorkflows(sess.FilePath)
allAgents, _ := session.FindSubagents(sess.FilePath)
a.sessWfAgents = session.JoinWorkflowAgents(a.sessWfRuns, allAgents)
a.sessWfRuns, a.sessWfAgents = nil, nil
a.sessWfCursor = 0
a.sessWorkflowsCacheKey = sess.ID
a.sessWorkflowsCacheKey = ""
}
cmd := a.adoptPreviewLoad(sessPreviewWorkflows, sess)
previewW := max(a.width-a.sessSplit.ListWidth(a.width, a.splitRatio)-1, 1)
contentH := max(a.height-3, 1)
a.sessSplit.Preview = viewport.New(previewW, contentH)
if _, loaded := a.previewLoads.Get(previewLoadKey(sessPreviewWorkflows, sess)); !loaded {
a.sessSplit.Preview.SetContent(dimStyle.Render("(loading workflows…)"))
return cmd
}
a.sessWorkflowsCacheKey = sess.ID
a.sessSplit.Preview.SetContent(a.buildWorkflowsPreviewContent(sess, previewW))
return cmd
}

// buildWorkflowsPreviewContent renders the workflow runs recorded for a session
Expand All @@ -6491,10 +6538,8 @@ func (a *App) updateSessionWorkflowsPreview(sess session.Session) {
// result). Agent rows are indexed to match a.sessWfAgents so the cursor maps to
// a real drill-down target.
func (a *App) buildWorkflowsPreviewContent(sess session.Session, width int) string {
// Loaded off the UI loop into sessWfRuns; see preview_load.go.
runs := a.sessWfRuns
if len(runs) == 0 {
runs, _ = session.FindWorkflows(sess.FilePath)
}
if len(runs) == 0 {
return dimStyle.Render("No workflow runs found.")
}
Expand Down Expand Up @@ -6654,44 +6699,61 @@ func formatDurationMS(ms int64) string {
return fmt.Sprintf("%dh%dm", int(d.Hours()), int(d.Minutes())%60)
}

func (a *App) updateSessionShellsPreview(sess session.Session) {
func (a *App) updateSessionShellsPreview(sess session.Session) tea.Cmd {
if a.sessShellsCacheKey != sess.ID {
a.sessShellsCache = a.buildShellsPreviewContent(sess)
a.sessShellsCacheKey = sess.ID
a.sessShellJobs = nil
a.sessShellsCache = ""
a.sessShellsCacheKey = ""
}
cmd := a.adoptPreviewLoad(sessPreviewShells, sess)
if a.sessShellsCacheKey != sess.ID {
if _, loaded := a.previewLoads.Get(previewLoadKey(sessPreviewShells, sess)); loaded {
a.sessShellsCache = a.buildShellsPreviewContent(sess)
a.sessShellsCacheKey = sess.ID
} else {
a.sessShellsCache = dimStyle.Render("(loading shells…)")
}
}
previewW := max(a.width-a.sessSplit.ListWidth(a.width, a.splitRatio)-1, 1)
contentH := max(a.height-3, 1)
a.sessSplit.Preview = viewport.New(previewW, contentH)
a.sessSplit.Preview.SetContent(a.sessShellsCache)
return cmd
}

func (a *App) updateSessionContextsPreview(sess session.Session) {
// updateSessionContextsPreview renders the context tree for a session. The
// tree itself is loaded off the UI loop (previewLoadCmd) and cached by
// session+mtime; only the render below is keyed by cursor/width/focus, so
// moving the highlight inside the pane no longer re-reads the transcript.
func (a *App) updateSessionContextsPreview(sess session.Session) tea.Cmd {
previewW := max(a.width-a.sessSplit.ListWidth(a.width, a.splitRatio)-1, 1)
contentH := max(a.height-3, 1)
// Reset the cursor when the selected session changes so we don't carry a
// stale index into a different tree.
if a.sessCtxCacheID != sess.ID {
a.sessCtxCursor = 0
a.sessCtxCacheID = sess.ID
a.sessCtxTree, a.sessCtxNodes, a.sessCtxErr = nil, nil, nil
}
// Cursor/focus are part of the key so highlight moves re-render.
cacheKey := fmt.Sprintf("%s:%d:%d:%d:%t", sess.ID, sess.ModTime.UnixNano(), previewW, a.sessCtxCursor, a.sessSplit.Focus)
if a.sessContextsCacheKey != cacheKey {
tree, err := session.BuildSessionContextTree(a.config.ClaudeDir, sess)
if err != nil {
a.sessContextsCache = dimStyle.Render("Failed to build context tree: " + err.Error())
a.sessCtxNodes = nil
} else {
a.sessCtxNodes = flattenContextNodes(tree)
if a.sessCtxCursor >= len(a.sessCtxNodes) {
a.sessCtxCursor = max(len(a.sessCtxNodes)-1, 0)
}
a.sessContextsCache = renderSessionContextTreeCursor(tree, previewW, a.sessCtxCursor, a.sessSplit.Focus)
cmd := a.adoptPreviewLoad(sessPreviewContexts, sess)
a.sessSplit.Preview = viewport.New(previewW, contentH)
switch {
case a.sessCtxErr != nil:
a.sessContextsCache = dimStyle.Render("Failed to build context tree: " + a.sessCtxErr.Error())
a.sessContextsCacheKey = ""
case a.sessCtxTree == nil:
a.sessContextsCache = dimStyle.Render("(loading context tree…)")
a.sessContextsCacheKey = ""
default:
// Cursor/focus/width are part of the key so highlight moves re-render.
cacheKey := fmt.Sprintf("%s:%d:%d:%d:%t", sess.ID, sess.ModTime.UnixNano(), previewW, a.sessCtxCursor, a.sessSplit.Focus)
if a.sessContextsCacheKey != cacheKey {
a.sessContextsCache = renderSessionContextTreeCursor(a.sessCtxTree, previewW, a.sessCtxCursor, a.sessSplit.Focus)
a.sessContextsCacheKey = cacheKey
}
a.sessContextsCacheKey = cacheKey
}
a.sessSplit.Preview = viewport.New(previewW, contentH)
a.sessSplit.Preview.SetContent(a.sessContextsCache)
return cmd
}

// updateSessionRefsPreview renders the PR/Jira references for a session with
Expand Down Expand Up @@ -7374,11 +7436,8 @@ func (a *App) buildShellsPreviewContent(sess session.Session) string {
}
jobs := sess.ShellJobs
if len(jobs) == 0 {
entries, err := session.LoadMessages(sess.FilePath)
if err != nil {
return dimStyle.Render("Failed to load session: " + err.Error())
}
jobs = session.LoadShellJobsFromEntries(entries)
// Parsed off the UI loop into sessShellJobs; see preview_load.go.
jobs = a.sessShellJobs
}
if len(jobs) == 0 {
return dimStyle.Render("No background shells or monitors found for this session.")
Expand Down Expand Up @@ -7612,15 +7671,15 @@ func (a *App) buildTasksPlanContent(sess session.Session) string {
}

func (a *App) buildAgentsPreviewContent(sess session.Session) string {
a.sessPreviewAgents = nil
if !sess.HasAgents {
a.sessPreviewAgents = nil
return dimStyle.Render("No agents found for this session.")
}
agents, err := session.FindSubagents(sess.FilePath)
if err != nil || len(agents) == 0 {
// Extracted off the UI loop into sessPreviewAgents; see preview_load.go.
agents := a.sessPreviewAgents
if len(agents) == 0 {
return dimStyle.Render("No agents found for this session.")
}
a.sessPreviewAgents = agents
if a.sessAgentCursor >= len(agents) {
a.sessAgentCursor = 0
}
Expand Down Expand Up @@ -7682,11 +7741,15 @@ func (a *App) buildAgentsPreviewContent(sess session.Session) string {
// name + size + mtime, then the (markdown-rendered) body for text files. This
// is the same level/surface as the memory preview — reachable via the `x` page
// menu key, `tab` cycling, and `preview:scratch`.
func (a *App) buildScratchpadContent(sess session.Session) string {
// buildScratchpadContent renders an already-loaded set of scratchpad files.
// The files are passed in rather than read here so the sessions pane can hand
// over what previewLoadCmd fetched off the UI loop (see preview_load.go) while
// the conversation inspector, reached by an explicit node selection rather than
// by row navigation, can still load them on the spot.
func (a *App) buildScratchpadContent(sess session.Session, files []session.ScratchpadFile) string {
if sess.ProjectPath == "" || sess.ID == "" {
return dimStyle.Render("(no session context)")
}
files := session.LoadScratchpadFiles(sess.ProjectPath, sess.ID)
if len(files) == 0 {
return dimStyle.Render("No scratchpad files.")
}
Expand Down
3 changes: 2 additions & 1 deletion internal/tui/conversation_inspector.go
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Original file line number Diff line number Diff line change
Expand Up @@ -516,7 +516,8 @@ func (a *App) renderInspectorOverview(item convItem, node session.FlowNode) stri
case "refs":
content = a.buildRefsListText()
case "scratchpad":
content = a.buildScratchpadContent(a.conv.sess)
content = a.buildScratchpadContent(a.conv.sess,
session.LoadScratchpadFiles(a.conv.sess.ProjectPath, a.conv.sess.ID))
default:
content = a.buildTasksPlanContent(a.conv.sess)
}
Expand Down
11 changes: 11 additions & 0 deletions internal/tui/outputs.go
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Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,17 @@ func (a *App) buildOutputsPreview(sess session.Session, dispatch bool) tea.Cmd {
// A transcript that grew invalidates the collection; the ref count is not
// part of the key because refs are merged in at render time, not collected.
dataKey := fmt.Sprintf("%s:%d", sess.ID, sess.ModTime.UnixNano())
// Adopt an earlier collection for this exact transcript before deciding to
// scan. Switching rows clears the single-session digest state above, so
// without this, moving the cursor off a row and back rescans its transcript
// — 8ms median, 117ms p95 per session, paid once per row per pass while
// walking the list.
if a.sessOutputsCollected != dataKey {
if cached, ok := a.sessOutputsStore.Get(dataKey); ok {
a.sessOutputs = cached
a.sessOutputsCollected = dataKey
}
}
if dispatch && a.sessOutputsCollected != dataKey && !a.outputsInFlight[sess.ID] {
a.outputsInFlight[sess.ID] = true
cmds = append(cmds, collectOutputsCmd(sess, dataKey))
Expand Down
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