[Bug]: benchmark_app crashes when an argument value contains '=' or is empty

Start with get_command_line_arguments() in tools/benchmark_tool/openvino/tools/benchmark/utils/utils.py, called from main.py after argument parsing. Reproduce both commands from the issue, including a model path containing '=' and an empty -i value. Done means both arguments are collected without a traceback and the -m value retains its full path.

OpenVINO Version

master (786821778a); also reproduces with openvino 2026.3.1 from PyPI

Operating System

Other (Please specify in description)

Device used for inference

CPU

Framework

ONNX

Model used

Not model specific

Issue description

benchmark_app ends in a traceback for two ordinary command lines that argparse has already accepted.

get_command_line_arguments() in tools/benchmark_tool/openvino/tools/benchmark/utils/utils.py is called from main.py on sys.argv right after argument parsing succeeds. It splits on = without a maxsplit and indexes arg[0] without checking for an empty string:

arg_name, arg_value = arg.split('=')   # no maxsplit
...
if arg[0] == '-':                      # unguarded index

A value that itself contains =:

$ benchmark_app -m=/data/exp=1/model.xml
[ ERROR ] too many values to unpack (expected 2)
  File ".../utils/utils.py", line 473, in get_command_line_arguments
    arg_name, arg_value = arg.split('=')
ValueError: too many values to unpack (expected 2)

An empty argument, which is what a shell passes when a variable used for an argument is unset (-i "$INPUT" with INPUT unset):

$ benchmark_app -m model.xml -i ""
[ ERROR ] string index out of range
  File ".../utils/utils.py", line 478, in get_command_line_arguments
    if arg[0] == '-':
IndexError: string index out of range

Neither is rejected by argparse, so the user gets a raw traceback from an internal helper rather than an argument error. The first is reachable from any model path below a directory containing =.

The repro host was Fedora 43 with Python 3.13, though nothing here is OS or model specific: both failures happen while collecting arguments, before any model is read.

Step-by-step reproduction

python3 -m venv venv
./venv/bin/pip install openvino
./venv/bin/benchmark_app -m=/data/exp=1/model.xml
./venv/bin/benchmark_app -m model.xml -i ""

Relevant log output

ValueError: too many values to unpack (expected 2)
IndexError: string index out of range

Expected: the arguments are collected without error, -m keeping the full path as its value.

Issue submission checklist

• I'm reporting an issue. It's not a question.
• I checked the problem with the documentation, FAQ, open issues, Stack Overflow, etc., and have not found a solution.
• There is reproducer code and related data files such as images, videos, models, etc.