Function writeGarbageExternalDiff

internal/diff/git_test.go:30–40

writeGarbageExternalDiff writes a shell script that emits non-diff output and returns its path. When git invokes it via GIT_EXTERNAL_DIFF / diff.external it replaces the normal unified-diff machinery, so the output can no longer be parsed into model.Diff structs unless the git command opts out with

(t *testing.T)

// parsed into model.Diff structs unless the git command opts out with
// --no-ext-diff.
func writeGarbageExternalDiff(t *testing.T) string {
	t.Helper()
	dir := t.TempDir()
	script := filepath.Join(dir, "garbage-diff.sh")
	// GIT_EXTERNAL_DIFF programs receive 7 args; we ignore them and print junk.
	body := "#!/bin/sh\necho \"not a diff\"\n"
	if err := os.WriteFile(script, []byte(body), 0o755); err != nil {
		t.Fatalf("write garbage diff script: %v", err)
	}
	return script
}

// initRepoWithChange creates a real git repository with one committed file and
// an uncommitted working-tree modification, returning the repo dir. There is a