Reapply "fix(ui): support unified diff patch format in session changes viewer"

This reverts commit af6429162f.

packages/ui/src/components/file-viewer/monaco-diff-viewer.tsx

@@ -1,15 +1,17 @@
-import { createEffect, createSignal, onCleanup, onMount } from "solid-js"
+import { createEffect, createMemo, createSignal, onCleanup, onMount } from "solid-js"
 import { loadMonaco } from "../../lib/monaco/setup"
 import { getOrCreateTextModel } from "../../lib/monaco/model-cache"
 import { inferMonacoLanguageId } from "../../lib/monaco/language"
 import { ensureMonacoLanguageLoaded } from "../../lib/monaco/setup"
 import { useTheme } from "../../lib/theme"
+import { parsePatchToBeforeAfter } from "../../lib/diff-utils"
 
 interface MonacoDiffViewerProps {
   scopeKey: string
   path: string
-  before: string
-  after: string
+  patch?: string
+  before?: string
+  after?: string
   viewMode?: "split" | "unified"
   contextMode?: "expanded" | "collapsed"
   wordWrap?: "on" | "off"
@@ -23,6 +25,16 @@ export function MonacoDiffViewer(props: MonacoDiffViewerProps) {
   let monaco: any = null
   const [ready, setReady] = createSignal(false)
 
+  const resolvedContent = createMemo(() => {
+    if (props.patch !== undefined && props.patch !== null) {
+      return parsePatchToBeforeAfter(props.patch)
+    }
+    return {
+      before: props.before ?? "",
+      after: props.after ?? "",
+    }
+  })
+
   const disposeEditor = () => {
     try {
       diffEditor?.setModel(null as any)
@@ -115,11 +127,12 @@ export function MonacoDiffViewer(props: MonacoDiffViewerProps) {
   createEffect(() => {
     if (!ready() || !monaco || !diffEditor) return
     const languageId = inferMonacoLanguageId(monaco, props.path)
+    const { before, after } = resolvedContent()
     const beforeKey = `${props.scopeKey}:diff:${props.path}:before`
     const afterKey = `${props.scopeKey}:diff:${props.path}:after`
 
-    const original = getOrCreateTextModel({ monaco, cacheKey: beforeKey, value: props.before, languageId })
-    const modified = getOrCreateTextModel({ monaco, cacheKey: afterKey, value: props.after, languageId })
+    const original = getOrCreateTextModel({ monaco, cacheKey: beforeKey, value: before, languageId })
+    const modified = getOrCreateTextModel({ monaco, cacheKey: afterKey, value: after, languageId })
     diffEditor.setModel({ original, modified })
 
     void ensureMonacoLanguageLoaded(languageId).then(() => {

packages/ui/src/components/instance/shell/right-panel/tabs/ChangesTab.tsx

@@ -115,23 +115,22 @@ const ChangesTab: Component<ChangesTabProps> = (props) => {
             }
           >
             {(file) => (
-              <Suspense
-                fallback={
-                  <div class="file-viewer-empty">
-                    <span class="file-viewer-empty-text">{props.t("instanceInfo.loading")}</span>
-                  </div>
-                }
-              >
-                <LazyMonacoDiffViewer
-                  scopeKey={scopeKey()}
-                  path={String(file().file || "")}
-                  before={String((file() as any).before || "")}
-                  after={String((file() as any).after || "")}
-                  viewMode={props.diffViewMode()}
-                  contextMode={props.diffContextMode()}
-                  wordWrap={props.diffWordWrapMode()}
-                />
-              </Suspense>
+<Suspense
+                  fallback={
+                    <div class="file-viewer-empty">
+                      <span class="file-viewer-empty-text">{props.t("instanceInfo.loading")}</span>
+                    </div>
+                  }
+                >
+                  <LazyMonacoDiffViewer
+                    scopeKey={scopeKey()}
+                    path={String(file().file || "")}
+                    patch={String((file() as any).patch || "")}
+                    viewMode={props.diffViewMode()}
+                    contextMode={props.diffContextMode()}
+                    wordWrap={props.diffWordWrapMode()}
+                  />
+                </Suspense>
             )}
           </Show>
         </div>

packages/ui/src/lib/diff-utils.ts

@@ -2,6 +2,7 @@ const HUNK_PATTERN = /(^|\n)@@/m
 const FILE_MARKER_PATTERN = /(^|\n)(diff --git |--- |\+\+\+)/
 const BEGIN_PATCH_PATTERN = /^\*\*\* (Begin|End) Patch/
 const UPDATE_FILE_PATTERN = /^\*\*\* Update File: (.+)$/
+const HUNK_HEADER_PATTERN = /^@@ -(\d+)(?:,(\d+))? \+(\d+)(?:,(\d+))? @@/
 
 function stripCodeFence(value: string): string {
   const trimmed = value.trim()
@@ -48,3 +49,48 @@ export function isRenderableDiffText(raw?: string | null): raw is string {
   if (!normalized) return false
   return HUNK_PATTERN.test(normalized)
 }
+
+export function parsePatchToBeforeAfter(patch: string): { before: string; after: string } {
+  if (!patch || patch.trim().length === 0) {
+    return { before: "", after: "" }
+  }
+
+  const lines = patch.replace(/\r\n/g, "\n").split("\n")
+  const beforeLines: string[] = []
+  const afterLines: string[] = []
+
+  for (const line of lines) {
+    if (line.startsWith("---") || line.startsWith("+++") || line.startsWith("diff --git")) {
+      continue
+    }
+    if (HUNK_HEADER_PATTERN.test(line)) {
+      continue
+    }
+    if (line.startsWith("-") && !line.startsWith("---")) {
+      beforeLines.push(line.slice(1))
+    } else if (line.startsWith("+") && !line.startsWith("+++")) {
+      afterLines.push(line.slice(1))
+    } else if (line.startsWith(" ")) {
+      beforeLines.push(line.slice(1))
+      afterLines.push(line.slice(1))
+    } else if (line === "") {
+      beforeLines.push("")
+      afterLines.push("")
+    } else {
+      beforeLines.push(line)
+      afterLines.push(line)
+    }
+  }
+
+  while (beforeLines.length > 0 && beforeLines[beforeLines.length - 1] === "") {
+    beforeLines.pop()
+  }
+  while (afterLines.length > 0 && afterLines[afterLines.length - 1] === "") {
+    afterLines.pop()
+  }
+
+  return {
+    before: beforeLines.join("\n"),
+    after: afterLines.join("\n"),
+  }
+}

packages/ui/src/types/session.ts

@@ -4,8 +4,7 @@ import type {
   Provider as SDKProvider,
   Model as SDKModel,
 } from "@opencode-ai/sdk"
-import type { SessionStatus as SDKSessionStatus } from "@opencode-ai/sdk/v2/client"
-import type { FileDiff } from "@opencode-ai/sdk/v2/client"
+import type { SessionStatus as SDKSessionStatus, FileDiff } from "@opencode-ai/sdk/v2/client"
 
 // Export SDK types for external use
 export type {