From ffbbc951809f8c4660afad1d367f70f9cc1ea0a0 Mon Sep 17 00:00:00 2001
From: Avishay Zarad <zarad.avishay@gmail.com>
Date: Sun, 26 Apr 2026 16:14:32 +0300
Subject: [PATCH] fix(git): pass --no-ext-diff to patch-emitting git diff calls

Patches consumed by parsePatchFiles (@pierre/diffs) honored the user's
diff.external config, so users with a structural differ set globally
(difftastic, delta-as-ext-diff, etc.) saw 'Unsupported diff format.
Showing raw patch.' in the diff panel.

Add --no-ext-diff to the three call sites whose stdout flows into
parsePatchFiles:
- CheckpointStore.diffCheckpoints
- GitCore.prepareCommitContext.stagedPatch
- GitCore.readRangeContext.diffPatch
---
 .../server/src/checkpointing/Layers/CheckpointStore.ts | 10 +++++++++-
 apps/server/src/git/Layers/GitCore.ts                  |  4 ++--
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/apps/server/src/checkpointing/Layers/CheckpointStore.ts b/apps/server/src/checkpointing/Layers/CheckpointStore.ts
index 211877e9b1a..df14c8f0294 100644
--- a/apps/server/src/checkpointing/Layers/CheckpointStore.ts
+++ b/apps/server/src/checkpointing/Layers/CheckpointStore.ts
@@ -246,7 +246,15 @@ const makeCheckpointStore = Effect.gen(function* () {
       const result = yield* git.execute({
         operation,
         cwd: input.cwd,
-        args: ["diff", "--patch", "--minimal", "--no-color", fromCommitOid, toCommitOid],
+        args: [
+          "diff",
+          "--no-ext-diff",
+          "--patch",
+          "--minimal",
+          "--no-color",
+          fromCommitOid,
+          toCommitOid,
+        ],
         maxOutputBytes: CHECKPOINT_DIFF_MAX_OUTPUT_BYTES,
       });
 
diff --git a/apps/server/src/git/Layers/GitCore.ts b/apps/server/src/git/Layers/GitCore.ts
index 3e9df316f1e..dc6ade4f6fe 100644
--- a/apps/server/src/git/Layers/GitCore.ts
+++ b/apps/server/src/git/Layers/GitCore.ts
@@ -1392,7 +1392,7 @@ export const makeGitCore = Effect.fn("makeGitCore")(function* (options?: {
     const stagedPatch = yield* runGitStdoutWithOptions(
       "GitCore.prepareCommitContext.stagedPatch",
       cwd,
-      ["diff", "--cached", "--patch", "--minimal"],
+      ["diff", "--no-ext-diff", "--cached", "--patch", "--minimal"],
       {
         maxOutputBytes: PREPARED_COMMIT_PATCH_MAX_OUTPUT_BYTES,
         truncateOutputAtMaxBytes: true,
@@ -1610,7 +1610,7 @@ export const makeGitCore = Effect.fn("makeGitCore")(function* (options?: {
           runGitStdoutWithOptions(
             "GitCore.readRangeContext.diffPatch",
             cwd,
-            ["diff", "--patch", "--minimal", range],
+            ["diff", "--no-ext-diff", "--patch", "--minimal", range],
             {
               maxOutputBytes: RANGE_DIFF_PATCH_MAX_OUTPUT_BYTES,
               truncateOutputAtMaxBytes: true,