Starting from llvm/llvm-project#70883 (around LLVM version 18.1.0), the clang-format-diff script now will exit with a non-zero status code if it detects there has formatting changes.
And this change from LLVM clang-format will break the assuming in apply-format script, here at L329,
  
  
    
        
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           "${git_args[@]}" "$@" \  | 
        
        
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               | "${format_diff_args[@]}" \  | 
        
        
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                   -p1 \  | 
        
        
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                   -style="$style" \  | 
        
        
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                   -iregex="$exclusions_regex"'.*\.(c|cpp|cxx|cc|h|hpp|m|mm|js|java)' \  | 
        
        
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                   > "$patch_dest" \  | 
        
        
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               || exit 1  | 
        
    
   
 
which stops apply-format to apply the diff as format fix to the local or git-staged files.