feat(tui): add last turn source to diff viewer

packages/tui/src/config/index.tsx

@@ -54,6 +54,10 @@ export const Plugin = Schema.Union([
   }),
 ])
 
+/** VCS review scopes plus the last session turn, which only exists while a session is open. */
+export const DiffSource = Schema.Union([Vcs.Mode, Schema.Literal("turn")])
+export type DiffSource = Schema.Schema.Type<typeof DiffSource>
+
 export const Cursor = Schema.Struct({
   style: Schema.optional(Schema.Literals(["block", "underline", "line", "default"])).annotate({
     description: "Cursor shape. Use 'default' to preserve the terminal setting",
@@ -109,8 +113,9 @@ export const Info = Schema.Struct({
   ).annotate({ description: "System notification and sound settings" }),
   diffs: Schema.optional(
     Schema.Struct({
-      source: Schema.optional(Vcs.Mode).annotate({
-        description: "Initial diff source; defaults to 'branch' (branch and uncommitted changes)",
+      source: Schema.optional(DiffSource).annotate({
+        description:
+          "Initial diff source; defaults to 'branch' (branch and uncommitted changes). 'turn' shows the last session turn and falls back to 'branch' outside a session",
       }),
       wrap: Schema.optional(Schema.Literals(["word", "none"])).annotate({
         description: "Line wrapping behavior in diff output",

packages/tui/src/feature-plugins/system/diff-viewer.tsx

@@ -21,7 +21,7 @@ import { EmptyBorder } from "../../ui/border"
 import { FilePath } from "../../ui/file-path"
 import { getScrollAcceleration } from "../../util/scroll"
 import { createDebouncedSignal } from "../../util/signal"
-import { useConfig } from "../../config"
+import { type DiffSource, useConfig } from "../../config"
 import { locationKey } from "../../context/data"
 import { useThemes } from "../../context/theme"
 import { PatchDiff, type PatchDiffRef } from "../../component/patch-diff"
@@ -44,7 +44,7 @@ const FILE_TREE_MIN_WIDTH = 30
 const FILE_TREE_MAX_WIDTH = 40
 const FILE_HEADER_HEIGHT = 2
 const VCS_DIFF_CONTEXT_LINES = 12
-type DiffMode = Vcs.Mode
+type DiffMode = DiffSource
 type DiffView = "split" | "unified"
 type SelectedHunk = { readonly fileIndex: number; readonly hunkIndex: number; readonly scrollTop: number }
 type FileMenuState = { readonly fileIndex: number; readonly x: number; readonly y: number }
@@ -73,9 +73,13 @@ function storedView(value: unknown): DiffView | undefined {
 function diffSourceLabel(mode: DiffMode) {
   if (mode === "branch") return "All"
   if (mode === "committed") return "Committed"
+  if (mode === "turn") return "Last turn"
   return "Uncommitted"
 }
 
+/** Branch comparisons resolve a review base; the working copy and the session turn do not. */
+const needsBase = (mode: DiffMode) => mode === "branch" || mode === "committed"
+
 function DiffViewer(props: { context: Plugin.Context }) {
   const dimensions = useTerminalDimensions()
   const config = useConfig()
@@ -93,12 +97,15 @@ function DiffViewer(props: { context: Plugin.Context }) {
         }
       | undefined
   }
-  const [mode, setMode] = createSignal(params()?.mode ?? memory.source ?? config.data.diffs?.source ?? "branch")
+  const sessionID = () => params()?.sessionID
+  const initialMode = params()?.mode ?? memory.source ?? config.data.diffs?.source ?? "branch"
+  // The session turn only exists inside a session; a remembered or configured turn source falls back elsewhere.
+  const [mode, setMode] = createSignal<DiffMode>(initialMode === "turn" && !sessionID() ? "branch" : initialMode)
   const location = createMemo(
     () => {
-      const sessionID = params()?.sessionID
-      return sessionID
-        ? (props.context.data.session.get(sessionID)?.location ?? props.context.data.location.default())
+      const id = sessionID()
+      return id
+        ? (props.context.data.session.get(id)?.location ?? props.context.data.location.default())
         : props.context.data.location.default()
     },
     undefined,
@@ -121,19 +128,30 @@ function DiffViewer(props: { context: Plugin.Context }) {
     bases.set(key, pending)
     return pending
   }
-  const diffInput = createMemo(() => ({
-    mode: mode(),
-    location: location(),
-    key: baseKey(),
-    selected: mode() === "working" ? undefined : selectedBase(),
-  }))
+  const diffInput = createMemo(() => {
+    const current = mode()
+    if (current === "turn") return { sessionID: sessionID() }
+    return {
+      mode: current,
+      location: location(),
+      key: baseKey(),
+      selected: needsBase(current) ? selectedBase() : undefined,
+    }
+  })
   const [diff] = createResource(diffInput, async (input) => {
-    const base =
-      input.mode === "working"
-        ? undefined
-        : input.selected
-          ? { name: input.selected, ref: input.selected }
-          : (await loadBase(input.location, input.key)).data
+    if ("sessionID" in input) {
+      if (!input.sessionID) return { base: null, files: [] }
+      const files = await props.context.client.session.diff({
+        sessionID: input.sessionID,
+        context: VCS_DIFF_CONTEXT_LINES,
+      })
+      return { base: null, files: normalizeDiffs(files) }
+    }
+    const base = !needsBase(input.mode)
+      ? undefined
+      : input.selected
+        ? { name: input.selected, ref: input.selected }
+        : (await loadBase(input.location, input.key)).data
     if (input !== diffInput() || (input.mode === "committed" && !base)) {
       return { base: null, files: [] }
     }
@@ -151,6 +169,7 @@ function DiffViewer(props: { context: Plugin.Context }) {
   }
   const result = () => (diff.error || diff.loading ? undefined : diff())
   const sourceDetail = () => {
+    if (mode() === "turn") return diff.error ? "Diff unavailable" : "since your last prompt"
     if (mode() === "working") return "vs HEAD"
     if (diff.error) return "Base or diff unavailable"
     if (!result()) return "Resolving diff…"
@@ -167,6 +186,7 @@ function DiffViewer(props: { context: Plugin.Context }) {
         loading={diff.loading}
         error={diff.error}
         mode={mode()}
+        turnSource={!!sessionID()}
         sourceDetail={sourceDetail()}
         sourceBase={sourceBase()}
         unavailable={mode() === "committed" && !!result() && !result()?.base}
@@ -261,6 +281,8 @@ export function DiffViewerContent(props: {
   loading?: boolean
   error?: unknown
   mode: DiffMode
+  /** Offer the session turn source; only meaningful when the viewer opened from a session. */
+  turnSource?: boolean
   sourceDetail?: string
   sourceBase?: Pick<Vcs.Base, "name" | "ref"> | null
   unavailable?: boolean
@@ -715,6 +737,14 @@ export function DiffViewerContent(props: {
         value: "working" as const,
         description: "Local changes only",
       },
+      ...(props.turnSource
+        ? [
+            {
+              value: "turn" as const,
+              description: "Since your last prompt",
+            },
+          ]
+        : []),
     ]
     dialog.show(() => (
       <DialogSelect<DiffMode | "base">
@@ -834,7 +864,7 @@ export function DiffViewerContent(props: {
           <Match when={!props.loading && props.error}>
             <box flexGrow={1} padding={2}>
               <text fg={theme.text.feedback.error.default}>
-                {!props.sourceBase && mode() !== "working"
+                {!props.sourceBase && needsBase(mode())
                   ? "Could not load diff. Choose a base branch from Diff source, or select Uncommitted."
                   : "Could not load diff. Reopen the diff viewer to try again."}
               </text>

packages/tui/test/cli/tui/diff-viewer.test.tsx

@@ -209,6 +209,68 @@ test("explicit route source overrides the configured default", async () => {
   }
 })
 
+test("the turn source diffs the session without resolving a base", async () => {
+  const viewer = await renderDiffViewer(hunkDiff, { height: 30, kittyKeyboard: true })
+  try {
+    await chooseSource(viewer, 3)
+    await viewer.app.waitForFrame((frame) => frame.includes("Last turn · since your last prompt"))
+    expect(viewer.app.captureCharFrame()).toContain("const first")
+    expect(viewer.turnDiffRequests).toHaveLength(1)
+    expect(viewer.turnDiffRequests[0].searchParams.get("context")).toBe("12")
+    expect(viewer.turnDiffRequests[0].searchParams.has("from")).toBe(false)
+    expect(viewer.diffRequests).toHaveLength(1)
+    expect(viewer.baseRequests).toHaveLength(1)
+    await chooseSource(viewer, 2)
+    await viewer.app.waitForFrame((frame) => frame.includes("Uncommitted · vs HEAD") && frame.includes("const first"))
+    expect(viewer.vcsDiffInput()).toEqual({
+      location: { directory: "/repo/session" },
+      mode: "working",
+      context: "12",
+    })
+  } finally {
+    viewer.app.renderer.destroy()
+  }
+})
+
+test("an empty or failing turn diff uses the viewer's empty and error states", async () => {
+  const empty = await renderDiffViewer([], { source: "turn", turnDiffResponse: async () => json({ data: [] }) })
+  try {
+    expect(empty.baseRequests).toHaveLength(0)
+    expect(empty.diffRequests).toHaveLength(0)
+    expect(empty.turnDiffRequests).toHaveLength(1)
+    await empty.app.waitForFrame((frame) => frame.includes("No changes to show"))
+  } finally {
+    empty.app.renderer.destroy()
+  }
+  const failing = await renderDiffViewer([], { source: "turn", fail: true })
+  try {
+    await failing.app.waitForFrame((frame) => frame.includes("Could not load diff. Reopen the diff viewer"))
+    expect(failing.app.captureCharFrame()).toContain("Last turn · Diff unavailable")
+    expect(failing.app.captureCharFrame()).not.toContain("Choose a base branch")
+  } finally {
+    failing.app.renderer.destroy()
+  }
+})
+
+test("the turn source is unavailable outside a session and falls back to the branch scope", async () => {
+  const viewer = await renderDiffViewer(hunkDiff, { source: "turn", height: 30, initialRoute: { type: "home" } })
+  try {
+    expect(viewer.vcsDiffInput()).toEqual({
+      location: { directory: "/repo/default" },
+      mode: "branch",
+      base: "refs/heads/v2",
+      context: "12",
+    })
+    expect(viewer.turnDiffRequests).toHaveLength(0)
+    viewer.app.mockInput.pressKey("d")
+    await viewer.app.waitForFrame((frame) => frame.includes("Diff source"))
+    expect(viewer.app.captureCharFrame()).not.toContain("Last turn")
+    expect(viewer.app.captureCharFrame()).toMatch(/Base\s+v2/)
+  } finally {
+    viewer.app.renderer.destroy()
+  }
+})
+
 test.each([50, 80, 160])(
   "keeps scope, base, and review count on one row with a selectable base at %i columns",
   async (width) => {
@@ -240,9 +302,11 @@ test.each([50, 80, 160])(
       expect(rows[first]).toMatch(/All\s+Branch \+ local changes/)
       expect(rows[first + 1]).toMatch(/Committed\s+Branch commits only/)
       expect(rows[first + 2]).toMatch(/Uncommitted\s+Local changes only/)
-      expect(rows[first + 3]).toMatch(/Base\s+release/)
+      expect(rows[first + 3]).toMatch(/Last turn\s+Since your last prompt/)
+      expect(rows[first + 4]).toMatch(/Base\s+release/)
       expect(rows[first + 1].indexOf("Branch commits only")).toBe(rows[first].indexOf("Branch + local changes"))
       expect(rows[first + 2].indexOf("Local changes only")).toBe(rows[first].indexOf("Branch + local changes"))
+      expect(rows[first + 3].indexOf("Since your last prompt")).toBe(rows[first].indexOf("Branch + local changes"))
       viewer.app.mockInput.pressEscape()
       await viewer.app.waitForFrame((frame) => !frame.includes("Diff source"))
       viewer.commands.get("diff.mark_reviewed")!.run()
@@ -292,7 +356,7 @@ test.each([50, 80, 100, 160])(
 )
 
 test("opening the source chooser from initial Uncommitted does not resolve a branch base", async () => {
-  const viewer = await renderDiffViewer(hunkDiff, { source: "working" })
+  const viewer = await renderDiffViewer(hunkDiff, { source: "working", height: 30 })
   try {
     viewer.app.mockInput.pressKey("d")
     await viewer.app.waitForFrame((frame) => frame.includes("Diff source"))
@@ -313,7 +377,7 @@ test.each(["branch", "committed", "working"] as const)(
       viewer.commands.get("diff.mark_reviewed")!.run()
       await viewer.app.flush()
       expect(viewer.app.captureCharFrame()).toContain("1/1")
-      await chooseSource(viewer, 3)
+      await chooseSource(viewer, 4)
       await viewer.app.waitForFrame((frame) => frame.includes("Base branch") && frame.includes("origin/release"))
       expect(viewer.app.captureCharFrame()).toMatch(/●\s+v2/)
       expect(viewer.branchesRequests[0].searchParams.get("location[directory]")).toBe("/repo/session")
@@ -347,7 +411,7 @@ test.each(["branch", "committed", "working"] as const)(
       expect(viewer.app.captureCharFrame()).toContain("0/1")
       expect(viewer.diffRequests).toHaveLength(source === "working" ? 2 : 3)
       if (source !== "working") expect(viewer.vcsDiffInput()).toMatchObject({ base: "origin/release" })
-      await chooseSource(viewer, 3)
+      await chooseSource(viewer, 4)
       await viewer.app.waitForFrame((frame) => /●\s+origin\/release/.test(frame))
       expect(viewer.baseRequests).toHaveLength(1)
     } finally {
@@ -371,7 +435,7 @@ test.each(["branch", "committed"] as const)("an ambiguous base never requests a
     expect(viewer.app.captureCharFrame()).toContain("Choose a base branch")
     expect(viewer.app.captureCharFrame()).not.toContain("No changes to show")
     expect(viewer.diffRequests).toHaveLength(0)
-    await chooseSource(viewer, 3)
+    await chooseSource(viewer, 4)
     await viewer.app.waitForFrame((frame) => frame.includes("Base branch") && frame.includes("origin/release"))
     viewer.app.mockInput.pressKey("HOME")
     viewer.app.mockInput.pressArrow("down")
@@ -388,7 +452,7 @@ test.each(["branch", "committed"] as const)("an ambiguous base never requests a
 test("base and scope choices survive reopening but not a new TUI instance", async () => {
   const viewer = await renderDiffViewer(hunkDiff, { source: "working", height: 30, kittyKeyboard: true })
   try {
-    await chooseSource(viewer, 3)
+    await chooseSource(viewer, 4)
     await viewer.app.waitForFrame((frame) => frame.includes("origin/release"))
     viewer.app.mockInput.pressArrow("down")
     viewer.app.mockInput.pressEnter()
@@ -421,7 +485,7 @@ test("base and scope choices survive reopening but not a new TUI instance", asyn
 test("base choices are isolated by branch within the same location", async () => {
   const viewer = await renderDiffViewer(hunkDiff, { height: 30, kittyKeyboard: true })
   try {
-    await chooseSource(viewer, 3)
+    await chooseSource(viewer, 4)
     await viewer.app.waitForFrame((frame) => frame.includes("origin/release"))
     viewer.app.mockInput.pressArrow("down")
     viewer.app.mockInput.pressEnter()
@@ -449,13 +513,13 @@ test("an invalid comparison reports an error and allows another base choice", as
         : json({ location: session.location, data: hunkDiff }),
   })
   try {
-    await chooseSource(viewer, 3)
+    await chooseSource(viewer, 4)
     await viewer.app.waitForFrame((frame) => frame.includes("origin/release"))
     viewer.app.mockInput.pressArrow("down")
     viewer.app.mockInput.pressEnter()
     await viewer.app.waitForFrame((frame) => frame.includes("Base or diff unavailable"))
     expect(viewer.app.captureCharFrame()).not.toContain("No changes to show")
-    await chooseSource(viewer, 3)
+    await chooseSource(viewer, 4)
     await viewer.app.waitForFrame((frame) => frame.includes("origin/release"))
     viewer.app.mockInput.pressKey("HOME")
     viewer.app.mockInput.pressEnter()
@@ -474,7 +538,7 @@ test("base search failures are visible without changing the diff", async () => {
     branchesResponse: async () => json({ message: "branches unavailable" }, { status: 503 }),
   })
   try {
-    await chooseSource(viewer, 3)
+    await chooseSource(viewer, 4)
     await viewer.app.waitForFrame((frame) => frame.includes("Could not load branches"))
     expect(viewer.app.captureCharFrame()).toContain("All · vs v2")
     expect(viewer.mutationRequests).toHaveLength(0)
@@ -493,7 +557,7 @@ test("a late base lookup cannot overwrite an in-memory base choice", async () =>
     baseResponse: () => pending.promise,
   })
   try {
-    await chooseSource(viewer, 3)
+    await chooseSource(viewer, 4)
     await viewer.app.waitForFrame((frame) => frame.includes("origin/release"))
     viewer.app.mockInput.pressArrow("down")
     viewer.app.mockInput.pressEnter()
@@ -522,7 +586,7 @@ test("dismissing the base picker leaves the comparison unchanged", async () => {
     kittyKeyboard: true,
   })
   try {
-    await chooseSource(viewer, 3)
+    await chooseSource(viewer, 4)
     await viewer.app.waitForFrame((frame) => frame.includes("origin/release"))
     viewer.app.mockInput.pressArrow("down")
     viewer.app.mockInput.pressEscape()
@@ -540,7 +604,7 @@ test("dismissing the base picker leaves the comparison unchanged", async () => {
 test("the base picker remembers its captured location without refreshing a moved session", async () => {
   const viewer = await renderDiffViewer(hunkDiff, { height: 30, kittyKeyboard: true })
   try {
-    await chooseSource(viewer, 3)
+    await chooseSource(viewer, 4)
     await viewer.app.waitForFrame((frame) => frame.includes("origin/release"))
     viewer.setSessionLocation({ directory: "/repo/moved" })
     await viewer.app.flush()
@@ -1800,12 +1864,13 @@ async function renderDiffViewer(
     onSessionTab?: () => void
     keybinds?: TuiKeybind.KeybindOverrides
     kittyKeyboard?: boolean
-    source?: "branch" | "committed" | "working"
+    source?: "branch" | "committed" | "working" | "turn"
     base?: typeof baseFixture | null
     open?: boolean
     pending?: boolean
     baseResponse?: () => Promise<Response>
     diffResponse?: (url: URL) => Promise<Response>
+    turnDiffResponse?: (url: URL) => Promise<Response>
     branchesResponse?: (url: URL) => Promise<Response>
     state?: string
   } = {},
@@ -1826,6 +1891,7 @@ async function renderDiffViewer(
   const writes: Info[] = []
   const baseRequests: URL[] = []
   const diffRequests: URL[] = []
+  const turnDiffRequests: URL[] = []
   const branchesRequests: URL[] = []
   const mutationRequests: URL[] = []
   const config = createTuiResolvedConfig(stored.info)
@@ -1858,6 +1924,12 @@ async function renderDiffViewer(
             ),
           })
     }
+    if (url.pathname === "/api/session/session-1/diff") {
+      turnDiffRequests.push(url)
+      if (options.turnDiffResponse) return options.turnDiffResponse(url)
+      if (options.fail) return json({ message: "boom" }, { status: 500 })
+      return json({ data: vcsDiff })
+    }
     if (url.pathname !== "/api/vcs/diff") return
     diffRequests.push(url)
     vcsDiffInput = {
@@ -2003,6 +2075,7 @@ async function renderDiffViewer(
     imageReadInput: () => imageReadInput,
     baseRequests,
     diffRequests,
+    turnDiffRequests,
     branchesRequests,
     mutationRequests,
     setSessionLocation,

packages/tui/test/config-v2.test.tsx

@@ -9,8 +9,8 @@ import { CommandMap, Definitions } from "../src/config/v1/keybind"
 
 const decodeInfo = Schema.decodeUnknownSync(Info)
 
-test("validates the three explicit diff source defaults", () => {
-  for (const source of ["branch", "committed", "working"] as const) {
+test("validates the four explicit diff source defaults", () => {
+  for (const source of ["branch", "committed", "working", "turn"] as const) {
     expect(decodeInfo({ diffs: { source } })).toEqual({ diffs: { source } })
   }
   expect(decodeInfo({ diffs: {} })).toEqual({ diffs: {} })

services/www/src/docs/content/cli/config.mdx

@@ -166,16 +166,18 @@ Configure diff presentation:
 }
 ```
 
-| Field    | Values                              | Description                                                   |
-| -------- | ----------------------------------- | ------------------------------------------------------------- |
-| `source` | `branch`, `committed`, or `working` | Sets the initial review scope. Defaults to `branch`.          |
-| `wrap`   | `word` or `none`                    | Sets line wrapping.                                           |
-| `tree`   | boolean                             | Shows the diff file tree.                                     |
-| `single` | boolean                             | Shows only the selected file patch.                           |
-| `view`   | `auto`, `split`, or `unified`       | Sets the layout. `auto` chooses based on the available width. |
+| Field    | Values                                      | Description                                                   |
+| -------- | ------------------------------------------- | ------------------------------------------------------------- |
+| `source` | `branch`, `committed`, `working`, or `turn` | Sets the initial review scope. Defaults to `branch`.          |
+| `wrap`   | `word` or `none`                            | Sets line wrapping.                                           |
+| `tree`   | boolean                                     | Shows the diff file tree.                                     |
+| `single` | boolean                                     | Shows only the selected file patch.                           |
+| `view`   | `auto`, `split`, or `unified`               | Sets the layout. `auto` chooses based on the available width. |
 
 `branch` shows **All** (branch and local changes), `committed` shows **Committed** (branch commits only), and `working` shows **Uncommitted** (staged, unstaged, and untracked changes).
 
+`turn` shows **Last turn**: the files the session changed since your last prompt. It is only available when `/diff` opens from a session and falls back to `branch` elsewhere.
+
 In `/diff`, press `d` to change the scope or choose a comparison branch from **Base**. OpenCode infers the base from local Git history when possible; otherwise it asks you to choose before loading a branch diff.
 
 Your base choice for each branch and last selected scope survive closing and reopening the viewer, but reset when the TUI exits. These selections do not change `cli.json`.