Hello dear bash-bug mailing-list!
I am puzzled by bash behavior with array assignments.
It seems there is a behavior change introduced in bash 4.3 in array
assignments. An array can actually reference itself in its own declaration.
$ declare -A foo=([bar]=1st) ; foo=([bar]=2nd [qwer]=${foo[bar]}) ; echo
"${foo[@]}"
2nd 2nd
$ bash --version
GNU bash, version 4.3.11(1)-release (x86_64-pc-linux-gnu)
$ declare -A foo=([bar]=1st) ; foo=([bar]=2nd [qwer]=${foo[bar]}) ; echo
"${foo[@]}"
2nd 1st
$ bash --version
GNU bash, version 4.2.25(1)-release (x86_64-pc-linux-gnu)
Is this a bug or a feature? I would have expected the bash <= 4.2 behavior to
be right on the principle you cannot define *and* use regular variables at the
same time. E.g.: "declare foo=bar gee=$foo" will not assign bar to gee. Plus,
regular arrays behave "normally" in both bash 4.2 and 4.3:
$ declare -a foo=(1st) ; foo=(2nd ${foo[0]}) ; echo ${foo[@]}
2nd 1st
$ bash --version
GNU bash, version 4.3.11(1)-release (x86_64-pc-linux-gnu)
$ declare -a foo=(1st) ; foo=(2nd ${foo[0]}) ; echo ${foo[@]}
2nd 1st
$ bash --version
GNU bash, version 4.2.25(1)-release (x86_64-pc-linux-gnu)
Another weirdness (I think) is this:
$ declare -A foo=([bar]=asdf [baz]=qwer) ; foo+=([bar]=asdf [baz]=qwer) ; echo
"${!foo[@]}" "${foo[@]}"
bar baz asdfasdf qwerqwer
Man page says :
When += is applied to an array variable using compound assignment (see Arrays
below), the variable's value is not unset (as it
is when using =), and new values are appended to the array beginning at one
greater than the array's maximum index (for indexed
arrays) or added as additional key-value pairs in an associative array.
There's nothing about appending content to already-existing values. Honestly, I
would expect the key/value to be replaced, but that could just be my mind being
too twisted.
Regards,
D
--
Damien Nadé <dnade....@orange.com>
Astek Sud-Est pour Orange/OF/DSIF/DFY/SFY/DO
Sophia Antipolis - France / Tel : 04 97 46 28 74
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