Merge branch 'dev' into review-git-changes

packages/app/src/context/global-sync/bootstrap.ts

@@ -158,7 +158,7 @@ export async function bootstrapDirectory(input: {
     input.sdk.vcs.get().then((x) => {
       const next = x.data ?? input.store.vcs
       input.setStore("vcs", next)
-      if (next?.branch) input.vcsCache.setStore("value", next)
+      if (next) input.vcsCache.setStore("value", next)
     }),
     input.sdk.permission.list().then((x) => {
       const grouped = groupBySession(

packages/app/src/context/global-sync/event-reducer.ts

@@ -268,9 +268,9 @@ export function applyDirectoryEvent(input: {
       break
     }
     case "vcs.branch.updated": {
-      const props = event.properties as { branch: string }
+      const props = event.properties as { branch?: string }
       if (input.store.vcs?.branch === props.branch) break
-      const next = { branch: props.branch }
+      const next = { ...input.store.vcs, branch: props.branch }
       input.setStore("vcs", next)
       if (input.vcsCache) input.vcsCache.setStore("value", next)
       break

packages/app/src/i18n/en.ts

@@ -532,6 +532,8 @@ export const dict = {
   "session.review.noVcs.createGit.action": "Create Git repository",
   "session.review.noSnapshot": "Snapshot tracking is disabled in config, so session changes are unavailable",
   "session.review.noChanges": "No changes",
+  "session.review.noUncommittedChanges": "No uncommitted changes yet",
+  "session.review.noBranchChanges": "No branch changes yet",
 
   "session.files.selectToOpen": "Select a file to open",
   "session.files.all": "All files",

packages/app/src/pages/session.tsx

@@ -1,4 +1,4 @@
-import type { Project, UserMessage } from "@opencode-ai/sdk/v2"
+import type { FileDiff, Project, UserMessage } from "@opencode-ai/sdk/v2"
 import { useDialog } from "@opencode-ai/ui/context/dialog"
 import {
   batch,
@@ -57,6 +57,9 @@ import { formatServerError } from "@/utils/server-errors"
 const emptyUserMessages: UserMessage[] = []
 const emptyFollowups: (FollowupDraft & { id: string })[] = []
 
+type ChangeMode = "git" | "branch" | "session" | "turn"
+type VcsMode = "git" | "branch"
+
 type SessionHistoryWindowInput = {
   sessionID: () => string | undefined
   messagesReady: () => boolean
@@ -415,15 +418,16 @@ export default function Page() {
 
   const info = createMemo(() => (params.id ? sync.session.get(params.id) : undefined))
   const diffs = createMemo(() => (params.id ? (sync.data.session_diff[params.id] ?? []) : []))
-  const reviewCount = createMemo(() => Math.max(info()?.summary?.files ?? 0, diffs().length))
-  const hasReview = createMemo(() => reviewCount() > 0)
+  const sessionCount = createMemo(() => Math.max(info()?.summary?.files ?? 0, diffs().length))
+  const hasSessionReview = createMemo(() => sessionCount() > 0)
+  const canReview = createMemo(() => !!params.id)
   const reviewTab = createMemo(() => isDesktop())
   const tabState = createSessionTabs({
     tabs,
     pathFromTab: file.pathFromTab,
     normalizeTab,
     review: reviewTab,
-    hasReview,
+    hasReview: canReview,
   })
   const contextOpen = tabState.contextOpen
   const openedTabs = tabState.openedTabs
@@ -499,11 +503,22 @@ export default function Page() {
   const [store, setStore] = createStore({
     messageId: undefined as string | undefined,
     mobileTab: "session" as "session" | "changes",
-    changes: "session" as "session" | "turn",
+    changes: "git" as ChangeMode,
     newSessionWorktree: "main",
     deferRender: false,
   })
 
+  const [vcs, setVcs] = createStore({
+    diff: {
+      git: [] as FileDiff[],
+      branch: [] as FileDiff[],
+    },
+    ready: {
+      git: false,
+      branch: false,
+    },
+  })
+
   const [followup, setFollowup] = createStore({
     items: {} as Record<string, (FollowupDraft & { id: string })[] | undefined>,
     sending: {} as Record<string, string | undefined>,
@@ -531,6 +546,40 @@ export default function Page() {
   let refreshTimer: number | undefined
   let diffFrame: number | undefined
   let diffTimer: number | undefined
+  const vcsTask = new Map<VcsMode, Promise<void>>()
+
+  const resetVcs = () => {
+    vcsTask.clear()
+    setVcs({
+      diff: { git: [], branch: [] },
+      ready: { git: false, branch: false },
+    })
+  }
+
+  const loadVcs = (mode: VcsMode, force = false) => {
+    if (sync.project?.vcs !== "git") return Promise.resolve()
+    if (vcs.ready[mode] && !force) return Promise.resolve()
+    const current = vcsTask.get(mode)
+    if (current) return current
+
+    const task = sdk.client.vcs
+      .diff({ mode })
+      .then((result) => {
+        setVcs("diff", mode, result.data ?? [])
+        setVcs("ready", mode, true)
+      })
+      .catch((error) => {
+        console.debug("[session-review] failed to load vcs diff", { mode, error })
+        setVcs("diff", mode, [])
+        setVcs("ready", mode, true)
+      })
+      .finally(() => {
+        vcsTask.delete(mode)
+      })
+
+    vcsTask.set(mode, task)
+    return task
+  }
 
   createComputed((prev) => {
     const open = desktopReviewOpen()
@@ -546,7 +595,38 @@ export default function Page() {
   }, desktopReviewOpen())
 
   const turnDiffs = createMemo(() => lastUserMessage()?.summary?.diffs ?? [])
-  const reviewDiffs = createMemo(() => (store.changes === "session" ? diffs() : turnDiffs()))
+  const changesOptions = createMemo<ChangeMode[]>(() => {
+    const list: ChangeMode[] = []
+    const git = sync.project?.vcs === "git"
+    if (git) list.push("git")
+    if (git && sync.data.vcs?.branch && sync.data.vcs?.default_branch && sync.data.vcs.branch !== sync.data.vcs.default_branch) {
+      list.push("branch")
+    }
+    list.push("session", "turn")
+    return list
+  })
+  const vcsMode = createMemo<VcsMode | undefined>(() => {
+    if (store.changes === "git" || store.changes === "branch") return store.changes
+  })
+  const reviewDiffs = createMemo(() => {
+    if (store.changes === "git") return vcs.diff.git
+    if (store.changes === "branch") return vcs.diff.branch
+    if (store.changes === "session") return diffs()
+    return turnDiffs()
+  })
+  const reviewCount = createMemo(() => {
+    if (store.changes === "git") return vcs.diff.git.length
+    if (store.changes === "branch") return vcs.diff.branch.length
+    if (store.changes === "session") return sessionCount()
+    return turnDiffs().length
+  })
+  const hasReview = createMemo(() => reviewCount() > 0)
+  const reviewReady = createMemo(() => {
+    if (store.changes === "git") return vcs.ready.git
+    if (store.changes === "branch") return vcs.ready.branch
+    if (store.changes === "session") return !hasSessionReview() || diffsReady()
+    return true
+  })
 
   const newSessionWorktree = createMemo(() => {
     if (store.newSessionWorktree === "create") return "create"
@@ -615,10 +695,10 @@ export default function Page() {
   const diffsReady = createMemo(() => {
     const id = params.id
     if (!id) return true
-    if (!hasReview()) return true
+    if (!hasSessionReview()) return true
     return sync.data.session_diff[id] !== undefined
   })
-  const reviewEmptyKey = createMemo(() => {
+  const sessionEmptyKey = createMemo(() => {
     const project = sync.project
     if (project && !project.vcs) return "session.review.noVcs"
     if (sync.data.config.snapshot === false) return "session.review.noSnapshot"
@@ -741,13 +821,23 @@ export default function Page() {
       sessionKey,
       () => {
         setStore("messageId", undefined)
-        setStore("changes", "session")
+        setStore("changes", "git")
         setUi("pendingMessage", undefined)
       },
       { defer: true },
     ),
   )
 
+  createEffect(
+    on(
+      () => sdk.directory,
+      () => {
+        resetVcs()
+      },
+      { defer: true },
+    ),
+  )
+
   createEffect(
     on(
       () => params.dir,
@@ -870,6 +960,38 @@ export default function Page() {
   }
 
   const mobileChanges = createMemo(() => !isDesktop() && store.mobileTab === "changes")
+  const wantsReview = createMemo(() =>
+    isDesktop() ? desktopFileTreeOpen() || (desktopReviewOpen() && activeTab() === "review") : store.mobileTab === "changes",
+  )
+
+  createEffect(() => {
+    const list = changesOptions()
+    if (list.includes(store.changes)) return
+    const next = list[0]
+    if (!next) return
+    setStore("changes", next)
+  })
+
+  createEffect(() => {
+    const mode = vcsMode()
+    if (!mode) return
+    if (!wantsReview()) return
+    void loadVcs(mode)
+  })
+
+  createEffect(
+    on(
+      () => sync.data.session_status[params.id ?? ""]?.type,
+      (next, prev) => {
+        const mode = vcsMode()
+        if (!mode) return
+        if (!wantsReview()) return
+        if (next !== "idle" || prev === undefined || prev === "idle") return
+        void loadVcs(mode, true)
+      },
+      { defer: true },
+    ),
+  )
 
   const fileTreeTab = () => layout.fileTree.tab()
   const setFileTreeTab = (value: "changes" | "all") => layout.fileTree.setTab(value)
@@ -916,21 +1038,23 @@ export default function Page() {
     loadFile: file.load,
   })
 
-  const changesOptions = ["session", "turn"] as const
-  const changesOptionsList = [...changesOptions]
-
   const changesTitle = () => {
-    if (!hasReview()) {
+    if (!canReview()) {
       return null
     }
 
+    const label = (option: ChangeMode) => {
+      if (option === "git") return language.t("ui.sessionReview.title.git")
+      if (option === "branch") return language.t("ui.sessionReview.title.branch")
+      if (option === "session") return language.t("ui.sessionReview.title")
+      return language.t("ui.sessionReview.title.lastTurn")
+    }
+
     return (
       <Select
-        options={changesOptionsList}
+        options={changesOptions()}
         current={store.changes}
-        label={(option) =>
-          option === "session" ? language.t("ui.sessionReview.title") : language.t("ui.sessionReview.title.lastTurn")
-        }
+        label={label}
         onSelect={(option) => option && setStore("changes", option)}
         variant="ghost"
         size="small"
@@ -939,20 +1063,34 @@ export default function Page() {
     )
   }
 
-  const emptyTurn = () => (
+  const empty = (text: string) => (
     <div class="h-full pb-64 -mt-4 flex flex-col items-center justify-center text-center gap-6">
-      <div class="text-14-regular text-text-weak max-w-56">{language.t("session.review.noChanges")}</div>
+      <div class="text-14-regular text-text-weak max-w-56">{text}</div>
     </div>
   )
 
-  const reviewEmpty = (input: { loadingClass: string; emptyClass: string }) => {
-    if (store.changes === "turn") return emptyTurn()
+  const reviewEmptyText = createMemo(() => {
+    if (store.changes === "git") return language.t("session.review.noUncommittedChanges")
+    if (store.changes === "branch") return language.t("session.review.noBranchChanges")
+    if (store.changes === "turn") return language.t("session.review.noChanges")
+    return language.t(sessionEmptyKey())
+  })
 
-    if (hasReview() && !diffsReady()) {
+  const reviewEmpty = (input: { loadingClass: string; emptyClass: string }) => {
+    if (store.changes === "git" || store.changes === "branch") {
+      if (!reviewReady()) return <div class={input.loadingClass}>{language.t("session.review.loadingChanges")}</div>
+      return empty(reviewEmptyText())
+    }
+
+    if (store.changes === "turn") {
+      return empty(reviewEmptyText())
+    }
+
+    if (hasSessionReview() && !diffsReady()) {
       return <div class={input.loadingClass}>{language.t("session.review.loadingChanges")}</div>
     }
 
-    if (reviewEmptyKey() === "session.review.noVcs") {
+    if (sessionEmptyKey() === "session.review.noVcs") {
       return (
         <div class={input.emptyClass}>
           <div class="flex flex-col gap-3">
@@ -972,7 +1110,7 @@ export default function Page() {
 
     return (
       <div class={input.emptyClass}>
-        <div class="text-14-regular text-text-weak max-w-56">{language.t(reviewEmptyKey())}</div>
+        <div class="text-14-regular text-text-weak max-w-56">{reviewEmptyText()}</div>
       </div>
     )
   }
@@ -1076,7 +1214,7 @@ export default function Page() {
     const pending = tree.pendingDiff
     if (!pending) return
     if (!tree.reviewScroll) return
-    if (!diffsReady()) return
+    if (!reviewReady()) return
 
     const attempt = (count: number) => {
       if (tree.pendingDiff !== pending) return
@@ -1808,6 +1946,12 @@ export default function Page() {
         </div>
 
         <SessionSidePanel
+          canReview={canReview}
+          diffs={reviewDiffs}
+          diffsReady={reviewReady}
+          empty={reviewEmptyText}
+          hasReview={hasReview}
+          reviewCount={reviewCount}
           reviewPanel={reviewPanel}
           activeDiff={tree.activeDiff}
           focusReviewDiff={focusReviewDiff}

packages/app/src/pages/session/session-side-panel.tsx

@@ -8,6 +8,7 @@ import { ResizeHandle } from "@opencode-ai/ui/resize-handle"
 import { Mark } from "@opencode-ai/ui/logo"
 import { DragDropProvider, DragDropSensors, DragOverlay, SortableProvider, closestCenter } from "@thisbeyond/solid-dnd"
 import type { DragEvent } from "@thisbeyond/solid-dnd"
+import type { FileDiff } from "@opencode-ai/sdk/v2"
 import { ConstrainDragYAxis, getDraggableId } from "@/utils/solid-dnd"
 import { useDialog } from "@opencode-ai/ui/context/dialog"
 
@@ -19,7 +20,6 @@ import { useCommand } from "@/context/command"
 import { useFile, type SelectedLineRange } from "@/context/file"
 import { useLanguage } from "@/context/language"
 import { useLayout } from "@/context/layout"
-import { useSync } from "@/context/sync"
 import { createFileTabListSync } from "@/pages/session/file-tab-scroll"
 import { FileTabContent } from "@/pages/session/file-tabs"
 import { createOpenSessionFileTab, createSessionTabs, getTabReorderIndex, type Sizing } from "@/pages/session/helpers"
@@ -27,6 +27,12 @@ import { setSessionHandoff } from "@/pages/session/handoff"
 import { useSessionLayout } from "@/pages/session/session-layout"
 
 export function SessionSidePanel(props: {
+  canReview: () => boolean
+  diffs: () => FileDiff[]
+  diffsReady: () => boolean
+  empty: () => string
+  hasReview: () => boolean
+  reviewCount: () => number
   reviewPanel: () => JSX.Element
   activeDiff?: string
   focusReviewDiff: (path: string) => void
@@ -34,12 +40,11 @@ export function SessionSidePanel(props: {
   size: Sizing
 }) {
   const layout = useLayout()
-  const sync = useSync()
   const file = useFile()
   const language = useLanguage()
   const command = useCommand()
   const dialog = useDialog()
-  const { params, sessionKey, tabs, view } = useSessionLayout()
+  const { sessionKey, tabs, view } = useSessionLayout()
 
   const isDesktop = createMediaQuery("(min-width: 768px)")
 
@@ -54,24 +59,7 @@ export function SessionSidePanel(props: {
   })
   const treeWidth = createMemo(() => (fileOpen() ? `${layout.fileTree.width()}px` : "0px"))
 
-  const info = createMemo(() => (params.id ? sync.session.get(params.id) : undefined))
-  const diffs = createMemo(() => (params.id ? (sync.data.session_diff[params.id] ?? []) : []))
-  const reviewCount = createMemo(() => Math.max(info()?.summary?.files ?? 0, diffs().length))
-  const hasReview = createMemo(() => reviewCount() > 0)
-  const diffsReady = createMemo(() => {
-    const id = params.id
-    if (!id) return true
-    if (!hasReview()) return true
-    return sync.data.session_diff[id] !== undefined
-  })
-
-  const reviewEmptyKey = createMemo(() => {
-    if (sync.project && !sync.project.vcs) return "session.review.noVcs"
-    if (sync.data.config.snapshot === false) return "session.review.noSnapshot"
-    return "session.review.noChanges"
-  })
-
-  const diffFiles = createMemo(() => diffs().map((d) => d.file))
+  const diffFiles = createMemo(() => props.diffs().map((d) => d.file))
   const kinds = createMemo(() => {
     const merge = (a: "add" | "del" | "mix" | undefined, b: "add" | "del" | "mix") => {
       if (!a) return b
@@ -82,7 +70,7 @@ export function SessionSidePanel(props: {
     const normalize = (p: string) => p.replaceAll("\\\\", "/").replace(/\/+$/, "")
 
     const out = new Map<string, "add" | "del" | "mix">()
-    for (const diff of diffs()) {
+    for (const diff of props.diffs()) {
       const file = normalize(diff.file)
       const kind = diff.status === "added" ? "add" : diff.status === "deleted" ? "del" : "mix"
 
@@ -136,7 +124,7 @@ export function SessionSidePanel(props: {
     pathFromTab: file.pathFromTab,
     normalizeTab,
     review: reviewTab,
-    hasReview,
+    hasReview: props.canReview,
   })
   const contextOpen = tabState.contextOpen
   const openedTabs = tabState.openedTabs
@@ -241,12 +229,12 @@ export function SessionSidePanel(props: {
                         onCleanup(stop)
                       }}
                     >
-                      <Show when={reviewTab()}>
+                      <Show when={reviewTab() && props.canReview()}>
                         <Tabs.Trigger value="review">
                           <div class="flex items-center gap-1.5">
                             <div>{language.t("session.tab.review")}</div>
-                            <Show when={hasReview()}>
-                              <div>{reviewCount()}</div>
+                            <Show when={props.hasReview()}>
+                              <div>{props.reviewCount()}</div>
                             </Show>
                           </div>
                         </Tabs.Trigger>
@@ -303,7 +291,7 @@ export function SessionSidePanel(props: {
                     </Tabs.List>
                   </div>
 
-                  <Show when={reviewTab()}>
+                  <Show when={reviewTab() && props.canReview()}>
                     <Tabs.Content value="review" class="flex flex-col h-full overflow-hidden contain-strict">
                       <Show when={activeTab() === "review"}>{props.reviewPanel()}</Show>
                     </Tabs.Content>
@@ -377,8 +365,8 @@ export function SessionSidePanel(props: {
               >
                 <Tabs.List>
                   <Tabs.Trigger value="changes" class="flex-1" classes={{ button: "w-full" }}>
-                    {reviewCount()}{" "}
-                    {language.t(reviewCount() === 1 ? "session.review.change.one" : "session.review.change.other")}
+                    {props.reviewCount()}{" "}
+                    {language.t(props.reviewCount() === 1 ? "session.review.change.one" : "session.review.change.other")}
                   </Tabs.Trigger>
                   <Tabs.Trigger value="all" class="flex-1" classes={{ button: "w-full" }}>
                     {language.t("session.files.all")}
@@ -386,9 +374,9 @@ export function SessionSidePanel(props: {
                 </Tabs.List>
                 <Tabs.Content value="changes" class="bg-background-stronger px-3 py-0">
                   <Switch>
-                    <Match when={hasReview()}>
+                    <Match when={props.hasReview() || !props.diffsReady()}>
                       <Show
-                        when={diffsReady()}
+                        when={props.diffsReady()}
                         fallback={
                           <div class="px-2 py-2 text-12-regular text-text-weak">
                             {language.t("common.loading")}
@@ -408,9 +396,7 @@ export function SessionSidePanel(props: {
                       </Show>
                     </Match>
                     <Match when={true}>
-                      {empty(
-                        language.t(sync.project && !sync.project.vcs ? "session.review.noChanges" : reviewEmptyKey()),
-                      )}
+                      {empty(props.empty())}
                     </Match>
                   </Switch>
                 </Tabs.Content>

packages/app/src/pages/session/use-session-commands.tsx

@@ -56,11 +56,7 @@ export const useSessionCommands = (actions: SessionCommandContext) => {
     if (!id) return
     return sync.session.get(id)
   }
-  const hasReview = () => {
-    const id = params.id
-    if (!id) return false
-    return Math.max(info()?.summary?.files ?? 0, (sync.data.session_diff[id] ?? []).length) > 0
-  }
+  const hasReview = () => !!params.id
   const normalizeTab = (tab: string) => {
     if (!tab.startsWith("file://")) return tab
     return file.tab(tab)

packages/opencode/src/project/vcs.ts

@@ -6,11 +6,228 @@ import { Instance } from "./instance"
 import { InstanceContext } from "@/effect/instance-context"
 import { FileWatcher } from "@/file/watcher"
 import { git } from "@/util/git"
+import { Filesystem } from "@/util/filesystem"
+import { Snapshot } from "@/snapshot"
 import { Effect, Layer, ServiceMap } from "effect"
+import path from "path"
 
 const log = Log.create({ service: "vcs" })
+const cfg = [
+  "-c",
+  "core.autocrlf=false",
+  "-c",
+  "core.fsmonitor=false",
+  "-c",
+  "core.longpaths=true",
+  "-c",
+  "core.symlinks=true",
+  "-c",
+  "core.quotepath=false",
+] as const
+
+type Base = { name: string; ref: string }
+
+async function mapLimit<T, R>(list: T[], limit: number, fn: (item: T) => Promise<R>) {
+  const size = Math.max(1, limit)
+  const out: R[] = new Array(list.length)
+  let idx = 0
+  await Promise.all(
+    Array.from({ length: Math.min(size, list.length) }, async () => {
+      while (true) {
+        const i = idx
+        idx += 1
+        if (i >= list.length) return
+        out[i] = await fn(list[i]!)
+      }
+    }),
+  )
+  return out
+}
+
+function out(result: { text(): string }) {
+  return result.text().trim()
+}
+
+async function run(cwd: string, args: string[]) {
+  return git([...cfg, ...args], { cwd })
+}
+
+async function branch(cwd: string) {
+  const result = await run(cwd, ["rev-parse", "--abbrev-ref", "HEAD"])
+  if (result.exitCode !== 0) return
+  const text = out(result)
+  return text || undefined
+}
+
+async function prefix(cwd: string) {
+  const result = await run(cwd, ["rev-parse", "--show-prefix"])
+  if (result.exitCode !== 0) return ""
+  return out(result)
+}
+
+async function branches(cwd: string) {
+  const result = await run(cwd, ["for-each-ref", "--format=%(refname:short)", "refs/heads"])
+  if (result.exitCode !== 0) return []
+  return out(result)
+    .split("\n")
+    .map((item) => item.trim())
+    .filter(Boolean)
+}
+
+async function remoteHead(cwd: string, remote: string) {
+  const result = await run(cwd, ["ls-remote", "--symref", remote, "HEAD"])
+  if (result.exitCode !== 0) return
+  for (const line of result.text().split("\n")) {
+    const match = /^ref: refs\/heads\/(.+)\tHEAD$/.exec(line.trim())
+    if (!match?.[1]) continue
+    return { name: match[1], ref: `${remote}/${match[1]}` } satisfies Base
+  }
+}
+
+async function primary(cwd: string) {
+  const result = await run(cwd, ["remote"])
+  const list =
+    result.exitCode !== 0
+      ? []
+      : out(result)
+          .split("\n")
+          .map((item) => item.trim())
+          .filter(Boolean)
+  if (list.includes("origin")) return "origin"
+  if (list.length === 1) return list[0]
+  if (list.includes("upstream")) return "upstream"
+  return list[0]
+}
+
+async function base(cwd: string) {
+  const remote = await primary(cwd)
+  if (remote) {
+    const head = await run(cwd, ["symbolic-ref", `refs/remotes/${remote}/HEAD`])
+    if (head.exitCode === 0) {
+      const ref = out(head).replace(/^refs\/remotes\//, "")
+      const name = ref.startsWith(`${remote}/`) ? ref.slice(`${remote}/`.length) : ""
+      if (name) return { name, ref } satisfies Base
+    }
+
+    const next = await remoteHead(cwd, remote)
+    if (next) return next
+  }
+
+  const list = await branches(cwd)
+  for (const name of ["main", "master"]) {
+    if (list.includes(name)) return { name, ref: name }
+  }
+}
+
+async function head(cwd: string) {
+  const result = await run(cwd, ["rev-parse", "--verify", "HEAD"])
+  return result.exitCode === 0
+}
+
+async function work(cwd: string, file: string) {
+  const full = path.join(cwd, file)
+  if (!(await Filesystem.exists(full))) return ""
+  const buf = await Filesystem.readBytes(full).catch(() => Buffer.alloc(0))
+  if (buf.includes(0)) return ""
+  return buf.toString("utf8")
+}
+
+async function show(cwd: string, ref: string, file: string, base: string) {
+  const target = base ? `${base}${file}` : file
+  const result = await run(cwd, ["show", `${ref}:${target}`])
+  if (result.exitCode !== 0) return ""
+  return result.text()
+}
+
+function kind(code: string | undefined): "added" | "deleted" | "modified" {
+  if (code?.startsWith("A")) return "added"
+  if (code?.startsWith("D")) return "deleted"
+  return "modified"
+}
+
+function count(text: string) {
+  if (!text) return 0
+  if (!text.endsWith("\n")) return text.split("\n").length
+  return text.slice(0, -1).split("\n").length
+}
+
+async function track(cwd: string, ref: string) {
+  const base = await prefix(cwd)
+  const names = await run(cwd, ["diff", "--no-ext-diff", "--no-renames", "--name-status", ref, "--", "."])
+  const nums = await run(cwd, ["diff", "--no-ext-diff", "--no-renames", "--numstat", ref, "--", "."])
+  const map = new Map<string, "added" | "deleted" | "modified">()
+  const list: Snapshot.FileDiff[] = []
+
+  for (const line of out(names).split("\n")) {
+    if (!line) continue
+    const [code, file] = line.split("\t")
+    if (!file) continue
+    map.set(file, kind(code))
+  }
+
+  const rows = out(nums).split("\n").filter(Boolean)
+  const next = await mapLimit(rows, 8, async (line) => {
+    const [adds, dels, file] = line.split("\t")
+    if (!file) return undefined
+    const binary = adds === "-" && dels === "-"
+    const status = map.get(file) ?? "modified"
+    const before = binary || status === "added" ? "" : await show(cwd, ref, file, base)
+    const after = binary || status === "deleted" ? "" : await work(cwd, file)
+    const add = binary ? 0 : Number.parseInt(adds || "0", 10)
+    const del = binary ? 0 : Number.parseInt(dels || "0", 10)
+    return {
+      file,
+      before,
+      after,
+      additions: Number.isFinite(add) ? add : 0,
+      deletions: Number.isFinite(del) ? del : 0,
+      status,
+    } satisfies Snapshot.FileDiff
+  })
+  for (const item of next) {
+    if (item) list.push(item)
+  }
+
+  const extra = await run(cwd, ["ls-files", "--others", "--exclude-standard", "--", "."])
+  const added = await mapLimit(out(extra).split("\n").filter(Boolean), 16, async (file) => {
+    if (map.has(file)) return undefined
+    const after = await work(cwd, file)
+    return {
+      file,
+      before: "",
+      after,
+      additions: count(after),
+      deletions: 0,
+      status: "added",
+    } satisfies Snapshot.FileDiff
+  })
+  for (const item of added) {
+    if (item) list.push(item)
+  }
+
+  return list.toSorted((a, b) => a.file.localeCompare(b.file))
+}
+
+async function birth(cwd: string) {
+  const result = await run(cwd, ["ls-files", "--cached", "--others", "--exclude-standard", "--", "."])
+  const list = await mapLimit(out(result).split("\n").filter(Boolean), 16, async (file) => {
+    const after = await work(cwd, file)
+    return {
+      file,
+      before: "",
+      after,
+      additions: count(after),
+      deletions: 0,
+      status: "added",
+    } satisfies Snapshot.FileDiff
+  })
+  return list.toSorted((a, b) => a.file.localeCompare(b.file))
+}
 
 export namespace Vcs {
+  export const Mode = z.enum(["git", "branch"])
+  export type Mode = z.infer<typeof Mode>
+
   export const Event = {
     BranchUpdated: BusEvent.define(
       "vcs.branch.updated",
@@ -22,7 +239,8 @@ export namespace Vcs {
 
   export const Info = z
     .object({
-      branch: z.string(),
+      branch: z.string().optional(),
+      default_branch: z.string().optional(),
     })
     .meta({
       ref: "VcsInfo",
@@ -34,6 +252,8 @@ export namespace VcsService {
   export interface Service {
     readonly init: () => Effect.Effect<void>
     readonly branch: () => Effect.Effect<string | undefined>
+    readonly defaultBranch: () => Effect.Effect<string | undefined>
+    readonly diff: (mode: Vcs.Mode) => Effect.Effect<Snapshot.FileDiff[]>
   }
 }
 
@@ -43,19 +263,15 @@ export class VcsService extends ServiceMap.Service<VcsService, VcsService.Servic
     Effect.gen(function* () {
       const instance = yield* InstanceContext
       let current: string | undefined
+      let root: Base | undefined
 
       if (instance.project.vcs === "git") {
         const currentBranch = async () => {
-          const result = await git(["rev-parse", "--abbrev-ref", "HEAD"], {
-            cwd: instance.project.worktree,
-          })
-          if (result.exitCode !== 0) return undefined
-          const text = result.text().trim()
-          return text || undefined
+          return branch(instance.directory)
         }
 
-        current = yield* Effect.promise(() => currentBranch())
-        log.info("initialized", { branch: current })
+        ;[current, root] = yield* Effect.promise(() => Promise.all([currentBranch(), base(instance.directory)]))
+        log.info("initialized", { branch: current, default_branch: root?.name })
 
         const unsubscribe = Bus.subscribe(
           FileWatcher.Event.Updated,
@@ -78,6 +294,24 @@ export class VcsService extends ServiceMap.Service<VcsService, VcsService.Servic
         branch: Effect.fn("VcsService.branch")(function* () {
           return current
         }),
+        defaultBranch: Effect.fn("VcsService.defaultBranch")(function* () {
+          return root?.name
+        }),
+        diff: Effect.fn("VcsService.diff")(function* (mode: Vcs.Mode) {
+          if (instance.project.vcs !== "git") return []
+          if (mode === "git") {
+            const ok = yield* Effect.promise(() => head(instance.directory))
+            return yield* Effect.promise(() => (ok ? track(instance.directory, "HEAD") : birth(instance.directory)))
+          }
+
+          if (!root) return []
+          if (current && current === root.name) return []
+          const ref = yield* Effect.promise(() => run(instance.project.worktree, ["merge-base", root.ref, "HEAD"]))
+          if (ref.exitCode !== 0) return []
+          const text = out(ref)
+          if (!text) return []
+          return yield* Effect.promise(() => track(instance.directory, text))
+        }),
       })
     }),
   )

packages/opencode/src/server/server.ts

@@ -41,6 +41,7 @@ import { websocket } from "hono/bun"
 import { HTTPException } from "hono/http-exception"
 import { errors } from "./error"
 import { Filesystem } from "@/util/filesystem"
+import { Snapshot } from "@/snapshot"
 import { QuestionRoutes } from "./routes/question"
 import { PermissionRoutes } from "./routes/permission"
 import { GlobalRoutes } from "./routes/global"
@@ -331,10 +332,39 @@ export namespace Server {
           },
         }),
         async (c) => {
-          const branch = await runPromiseInstance(VcsService.use((s) => s.branch()))
-          return c.json({
-            branch,
-          })
+          const [branch, default_branch] = await Promise.all([
+            runPromiseInstance(VcsService.use((s) => s.branch())),
+            runPromiseInstance(VcsService.use((s) => s.defaultBranch())),
+          ])
+          return c.json({ branch, default_branch })
+        },
+      )
+      .get(
+        "/vcs/diff",
+        describeRoute({
+          summary: "Get VCS diff",
+          description: "Retrieve the current git diff for the working tree or against the default branch.",
+          operationId: "vcs.diff",
+          responses: {
+            200: {
+              description: "VCS diff",
+              content: {
+                "application/json": {
+                  schema: resolver(Snapshot.FileDiff.array()),
+                },
+              },
+            },
+          },
+        }),
+        validator(
+          "query",
+          z.object({
+            mode: Vcs.Mode,
+          }),
+        ),
+        async (c) => {
+          const mode = c.req.valid("query").mode
+          return c.json(await runPromiseInstance(VcsService.use((s) => s.diff(mode))))
         },
       )
       .get(

packages/opencode/test/project/vcs.test.ts

@@ -34,6 +34,10 @@ function withVcs(
   )
 }
 
+function withVcsOnly(directory: string, body: (rt: ManagedRuntime.ManagedRuntime<VcsService, never>) => Promise<void>) {
+  return withServices(directory, VcsService.layer, body)
+}
+
 type BranchEvent = { directory?: string; payload: { type: string; properties: { branch?: string } } }
 
 /** Wait for a Vcs.Event.BranchUpdated event on GlobalBus */
@@ -115,3 +119,75 @@ describeVcs("Vcs", () => {
     })
   })
 })
+
+describe("Vcs diff", () => {
+  afterEach(() => Instance.disposeAll())
+
+  test("defaultBranch() falls back to main", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await $`git branch -M main`.cwd(tmp.path).quiet()
+
+    await withVcsOnly(tmp.path, async (rt) => {
+      const branch = await rt.runPromise(VcsService.use((s) => s.defaultBranch()))
+      expect(branch).toBe("main")
+    })
+  })
+
+  test("detects current branch from the active worktree", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await using wt = await tmpdir()
+    await $`git branch -M main`.cwd(tmp.path).quiet()
+    const dir = path.join(wt.path, "feature")
+    await $`git worktree add -b feature/test ${dir} HEAD`.cwd(tmp.path).quiet()
+
+    await withVcsOnly(dir, async (rt) => {
+      const [branch, base] = await Promise.all([
+        rt.runPromise(VcsService.use((s) => s.branch())),
+        rt.runPromise(VcsService.use((s) => s.defaultBranch())),
+      ])
+      expect(branch).toBe("feature/test")
+      expect(base).toBe("main")
+    })
+  })
+
+  test("diff('git') returns uncommitted changes", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await fs.writeFile(path.join(tmp.path, "file.txt"), "original\n", "utf-8")
+    await $`git add .`.cwd(tmp.path).quiet()
+    await $`git commit --no-gpg-sign -m "add file"`.cwd(tmp.path).quiet()
+    await fs.writeFile(path.join(tmp.path, "file.txt"), "changed\n", "utf-8")
+
+    await withVcsOnly(tmp.path, async (rt) => {
+      const diff = await rt.runPromise(VcsService.use((s) => s.diff("git")))
+      expect(diff).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            file: "file.txt",
+            status: "modified",
+          }),
+        ]),
+      )
+    })
+  })
+
+  test("diff('branch') returns changes against default branch", async () => {
+    await using tmp = await tmpdir({ git: true })
+    await $`git branch -M main`.cwd(tmp.path).quiet()
+    await $`git checkout -b feature/test`.cwd(tmp.path).quiet()
+    await fs.writeFile(path.join(tmp.path, "branch.txt"), "hello\n", "utf-8")
+    await $`git add .`.cwd(tmp.path).quiet()
+    await $`git commit --no-gpg-sign -m "branch file"`.cwd(tmp.path).quiet()
+
+    await withVcsOnly(tmp.path, async (rt) => {
+      const diff = await rt.runPromise(VcsService.use((s) => s.diff("branch")))
+      expect(diff).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            file: "branch.txt",
+            status: "added",
+          }),
+        ]),
+      )
+    })
+  })
+})

packages/sdk/js/src/v2/gen/sdk.gen.ts

@@ -172,6 +172,7 @@ import type {
   TuiSelectSessionResponses,
   TuiShowToastResponses,
   TuiSubmitPromptResponses,
+  VcsDiffResponses,
   VcsGetResponses,
   WorktreeCreateErrors,
   WorktreeCreateInput,
@@ -3657,6 +3658,38 @@ export class Vcs extends HeyApiClient {
       ...params,
     })
   }
+
+  /**
+   * Get VCS diff
+   *
+   * Retrieve the current git diff for the working tree or against the default branch.
+   */
+  public diff<ThrowOnError extends boolean = false>(
+    parameters: {
+      directory?: string
+      workspace?: string
+      mode: "git" | "branch"
+    },
+    options?: Options<never, ThrowOnError>,
+  ) {
+    const params = buildClientParams(
+      [parameters],
+      [
+        {
+          args: [
+            { in: "query", key: "directory" },
+            { in: "query", key: "workspace" },
+            { in: "query", key: "mode" },
+          ],
+        },
+      ],
+    )
+    return (options?.client ?? this.client).get<VcsDiffResponses, unknown, ThrowOnError>({
+      url: "/vcs/diff",
+      ...options,
+      ...params,
+    })
+  }
 }
 
 export class Command extends HeyApiClient {

packages/sdk/js/src/v2/gen/types.gen.ts

@@ -1861,7 +1861,8 @@ export type Path = {
 }
 
 export type VcsInfo = {
-  branch: string
+  branch?: string
+  default_branch?: string
 }
 
 export type Command = {
@@ -4799,6 +4800,26 @@ export type VcsGetResponses = {
 
 export type VcsGetResponse = VcsGetResponses[keyof VcsGetResponses]
 
+export type VcsDiffData = {
+  body?: never
+  path?: never
+  query: {
+    directory?: string
+    workspace?: string
+    mode: "git" | "branch"
+  }
+  url: "/vcs/diff"
+}
+
+export type VcsDiffResponses = {
+  /**
+   * VCS diff
+   */
+  200: Array<FileDiff>
+}
+
+export type VcsDiffResponse = VcsDiffResponses[keyof VcsDiffResponses]
+
 export type CommandListData = {
   body?: never
   path?: never

packages/ui/src/i18n/en.ts

@@ -1,5 +1,7 @@
 export const dict: Record<string, string> = {
   "ui.sessionReview.title": "Session changes",
+  "ui.sessionReview.title.git": "Git changes",
+  "ui.sessionReview.title.branch": "Branch changes",
   "ui.sessionReview.title.lastTurn": "Last turn changes",
   "ui.sessionReview.diffStyle.unified": "Unified",
   "ui.sessionReview.diffStyle.split": "Split",