[clang] [clang-format][NFC] Skip ObjCHeaderStyleGuesser for empty code (PR #82957)

[Owen Pan via cfe-commits]

https://github.com/owenca created https://github.com/llvm/llvm-project/pull/82957

None

>From 9334d008b4c7ae13fdeb674a6bb9b4dc62c6a1dd Mon Sep 17 00:00:00 2001
From: Owen Pan <owenpiano at gmail.com>
Date: Sun, 25 Feb 2024 20:58:25 -0800
Subject: [PATCH] [clang-format][NFC] Skip ObjCHeaderStyleGuesser for empty
 code

---
 clang/lib/Format/Format.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 2f6b52510099a7..00ffc6718e052b 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -3920,7 +3920,7 @@ FormatStyle::LanguageKind guessLanguage(StringRef FileName, StringRef Code) {
     auto Extension = llvm::sys::path::extension(FileName);
     // If there's no file extension (or it's .h), we need to check the contents
     // of the code to see if it contains Objective-C.
-    if (Extension.empty() || Extension == ".h") {
+    if (!Code.empty() && (Extension.empty() || Extension == ".h")) {
       auto NonEmptyFileName = FileName.empty() ? "guess.h" : FileName;
       Environment Env(Code, NonEmptyFileName, /*Ranges=*/{});
       ObjCHeaderStyleGuesser Guesser(Env, getLLVMStyle());