fix(vcs): preserve batched patch boundaries (#25787)

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

@@ -1,5 +1,6 @@
 import { $ } from "bun"
 import { afterEach, describe, expect, test } from "bun:test"
+import { parsePatch } from "diff"
 import { Effect } from "effect"
 import fs from "fs/promises"
 import path from "path"
@@ -288,6 +289,32 @@ describe("Vcs diff", () => {
     })
   })
 
+  test(
+    "diff('git') keeps carriage returns inside patch hunks",
+    async () => {
+      await using tmp = await tmpdir({ git: true })
+      await fs.writeFile(path.join(tmp.path, "file.txt"), "keep\nsame\rdiff --git inside\ndelete\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"), "keep\nadd\nsame\rdiff --git inside\n", "utf-8")
+
+      await withVcsOnly(tmp.path, async () => {
+        const diff = await AppRuntime.runPromise(
+          Effect.gen(function* () {
+            const vcs = yield* Vcs.Service
+            return yield* vcs.diff("git")
+          }),
+        )
+        const file = diff.find((item) => item.file === "file.txt")
+
+        expect(file?.patch).toContain(" same\rdiff --git inside")
+        expect(file?.patch).toContain("-delete")
+        expect(() => parsePatch(file?.patch ?? "")).not.toThrow()
+      })
+    },
+    20_000,
+  )
+
   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()