apply_patch turns CRLF files into mixed line endings #45926

Activity

1. github-actions

   assigned

   rekram1-node

   on Aug 28, 2026
2. github-actions commented on Aug 28, 2026

   

   github-actionsBot

   on Aug 28, 2026 – with GitHub Actions

   Contributor

   More actions

   This issue might be a duplicate of existing issues. Please check:

   • Tool apply_patch messes up line endings in windows #37090: apply_patch messes up line endings on Windows (CRLF → LF introduced on new/edited lines)

   The root cause described there overlaps significantly with this report. It may be worth coordinating or referencing that issue.
3. pengzh1 commented on Aug 28, 2026

   

   pengzh1

   on Aug 28, 2026

   More actions

   Taking this — will preserve each line's original ending when splicing hunks in the patch path (LF context from read shouldn't rewrite CRLF lines), with a unit test on the exact derive repro.
4. neriousy

   marked Opencode v2: Tool Patch messes up line endings in Windows #54605 as a duplicate of this issue on Oct 20, 2026
5. Mac-Moneysac commented on Oct 22, 2026

   

   Mac-Moneysac

   on Oct 22, 2026

   More actions

   Hi, I workarounded it via a plugin which I've written: https://github.com/Mac-Moneysac/opencode-fix-line-endings

   It preserves line endings. If it is a new file, platform native line endings are used. It is also available via npm. However, it is still a workaround.
6. opencodejr commented on Oct 28, 2026

   

   opencodejrBot

   on Oct 28, 2026

   Contributor

   More actions

   Thanks for the clear report. I reproduced this on 2.2.0, and it still happens on the latest dev (506ac20c).

   What I did:

   • A simulated model read a 4-line CRLF file app.ts.
   • It used the patch tool to change one line and add one.
   • It then ran cat -A app.ts.

   Every line inside the hunk, including the unchanged context lines, came out LF ($). The untouched last line kept CRLF (^M$), so the file ends up with mixed line endings.

   Your unit-level example also behaves as you describe on dev: Patch.derive("f", [{ oldLines: ["foo"], newLines: ["FOO"] }], "foo\r\nbar\r\n") returns "FOO\nbar\r\n".

   The recording and screenshots below show the patch and the cat -A output, and the script below reproduces it. On dev the script may exit with a timeout at its final wait, even though the screen shows the same result.

   Related: #54605 (the same problem on Windows with v2.0.26, closed as a duplicate of this issue), and the open PRs #56128 and #58324, which both try to fix it.

   recording.mp4

   

   

   Reproduction script (drive.ts)

   // Repro for anomalyco/opencode#45926: the patch tool writes LF line endings into a CRLF file.
   // The simulated model patches one line of a CRLF file, then runs `cat -A app.ts`
   // (CRLF lines end in "^M$", LF lines in "$") so the result shows on screen.
   import { Effect, Stream } from "effect"
   import { Llm, OpenCodeDriver } from "opencode-drive"
   
   const patchText = [
     "*** Begin Patch",
     "*** Update File: app.ts",
     "@@",
     " const a = 1",
     "-const b = 2",
     "+const b = 20",
     "+const extra = 3",
     " const c = 3",
     "*** End Patch",
   ].join("\n")
   
   export default OpenCodeDriver.use(
     {
       ...(process.env.OC_DEV ? { opencode: { dev: process.env.OC_DEV } } : {}),
       tui: { recording: true },
       project: {
         git: true,
         files: { "app.ts": "const a = 1\r\nconst b = 2\r\nconst c = 3\r\nconst d = 4\r\n" },
       },
     },
     ({ ui, llm }) =>
       Effect.gen(function* () {
         const responses = [
           [Llm.toolCall({ index: 0, id: "call_read", name: "read", input: { path: "app.ts" } }), Llm.finish("tool-calls")],
           [Llm.toolCall({ index: 0, id: "call_patch", name: "patch", input: { patchText } }), Llm.finish("tool-calls")],
           [
             Llm.toolCall({ index: 0, id: "call_cat", name: "shell", input: { command: "cat -A app.ts", description: "Show line endings" } }),
             Llm.finish("tool-calls"),
           ],
           [Llm.text("Lines ending in ^M$ are CRLF, lines ending in $ are LF.")],
         ]
         yield* llm.serve((_request, index) => Stream.make(...(responses[index] ?? [Llm.text("end")])))
         yield* ui.submit("Change b to 20 in app.ts and add a line, then show line endings")
         yield* ui.waitFor("are CRLF", { timeout: 60000 })
         yield* Effect.sleep(1500)
         yield* ui.screenshot("after-patch")
       }),
   )

   Run it with opencode-drive: opencode-drive run ./drive.ts. It drives opencode from your PATH; set OC_DEV to the path of an OpenCode checkout to run that from source instead.
7. opencodejr

   added

   reproduced

   on Oct 28, 2026