linux - '声明-A x' 与 'declare -A x=()'

Question

我使用的是 4.2.53(1)-release，由 Fedora 20 运行。

以下两段代码表现不同，谁能告诉我为什么？谢谢。

[hidden]$ unset x; declare -p x; function f() { declare -A -g x; x[10]=100; }; f; declare -p x;
-bash: declare: x: not found
declare -A x='([10]="100" )'
[hidden]$ unset x; declare -p x; function f() { declare -A -g x=(); x[10]=100; }; f; declare -p x;
-bash: declare: x: not found
declare -A x='()'

Answer 1

这是 4.0-4.2 中的错误。这是fixed in 4.3 :

ddd. Fixed several bugs that caused `declare -g' to not set the right global
     variables or to misbehave when declaring global indexed arrays.

这是 4.3 的结果，它们的行为相同:

$ echo $BASH_VERSION
4.3.11(1)-release

$ unset x; declare -p x; function f() { declare -A -g x; x[10]=100; }; f; declare -p x;
bash: declare: x: not found
declare -A x='([10]="100" )'

$  unset x; declare -p x; function f() { declare -A -g x=(); x[10]=100; }; f; declare -p x;
bash: declare: x: not found
declare -A x='([10]="100" )'