Bug(esp_modem): get_network_registration_state fails to parse state value from AT+CEREG? response (IDFGH-16683) #923
Description
Description
The function get_network_registration_state fails to correctly parse the network registration status from the AT+CEREG? command response (e.g., +CEREG: 2,1).
Steps to Reproduce
Call get_network_registration_state.
The underlying AT command returns a valid response like +CEREG: 2,1.
The function attempts to use std::from_chars to parse the state.
Expected Behavior
The function should correctly extract the integer state (e.g., 1) and return command_result::OK.
Actual Behavior
The function fails because it attempts to parse the state value starting at the preceding comma delimiter (e.g., attempting to parse ,1 instead of 1), leading to an std::errc::invalid_argument error from std::from_chars. The function incorrectly returns command_result::FAIL.
Proposed Solution
The parsing index needs to be adjusted by one (+ 1) to skip the comma delimiter, ensuring std::from_chars starts at the first digit of the state value.