Configuration Information [Automatically generated, do not change]: Machine: x86_64 OS: linux-gnu Compiler: gcc Compilation CFLAGS: -march=x86-64 -mtune=generic -O2 -pipe -fno-plt -DDEFAULT_PATH_VALUE='/usr/local/sbin:/usr/local/bin:/usr/bin' -DSTANDARD_UTILS_PATH='/usr/bin' -DSYS_BASHRC='/etc/bash.bashrc' -DSYS_BASH_LOGOUT='/etc/bash.bash_logout' -DNON_INTERACTIVE_LOGIN_SHELLS uname output: Linux t420 5.15.32-1-lts #1 SMP Mon, 28 Mar 2022 08:54:31 +0000 x86_64 GNU/Linux Machine Type: x86_64-pc-linux-gnu
Bash Version: 5.1 Patch Level: 16 Release Status: release Description: `${var@A}' only expands to something if either var is set or is declared with attributes; it doesn't expand to `declare -- var' for variables that are declared but don't have any attribute and are unset. Shouldn't it expand to `declare -- var' and only expand to the empty string if the variable is not declared? emanuele6 Repeat-By: bash-5.1$ printf '%s\n' "${hello@A}" bash-5.1$ declare hello; printf '%s\n' "${hello@A}" bash-5.1$ x () { local hello; printf '%s\n' "${hello@A}" ;}; x bash-5.1$ declare -i hello; printf '%s\n' "${hello@A}" declare -i hello bash-5.1$ x () { local -u hello; printf '%s\n' "${hello@A}" ;}; x declare -u hello