core: prevent external diff tools from interfering with snapshot generation

packages/opencode/src/snapshot/index.ts

@@ -48,7 +48,7 @@ export namespace Snapshot {
     const git = gitdir()
     await $`git --git-dir ${git} --work-tree ${Instance.worktree} add .`.quiet().cwd(Instance.directory).nothrow()
     const result =
-      await $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${Instance.worktree} diff --name-only ${hash} -- .`
+      await $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${Instance.worktree} diff --no-ext-diff --name-only ${hash} -- .`
         .quiet()
         .cwd(Instance.directory)
         .nothrow()
@@ -126,7 +126,7 @@ export namespace Snapshot {
     const git = gitdir()
     await $`git --git-dir ${git} --work-tree ${Instance.worktree} add .`.quiet().cwd(Instance.directory).nothrow()
     const result =
-      await $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${Instance.worktree} diff ${hash} -- .`
+      await $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${Instance.worktree} diff --no-ext-diff ${hash} -- .`
         .quiet()
         .cwd(Instance.worktree)
         .nothrow()
@@ -159,7 +159,7 @@ export namespace Snapshot {
   export async function diffFull(from: string, to: string): Promise<FileDiff[]> {
     const git = gitdir()
     const result: FileDiff[] = []
-    for await (const line of $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${Instance.worktree} diff --no-renames --numstat ${from} ${to} -- .`
+    for await (const line of $`git -c core.autocrlf=false --git-dir ${git} --work-tree ${Instance.worktree} diff --no-ext-diff --no-renames --numstat ${from} ${to} -- .`
       .quiet()
       .cwd(Instance.directory)
       .nothrow()