Pattern: Use of [index]=
Issue: -
You have an array element on the form [index]=. The shell will interpret this as an independent element with index index and value <empty string>.
This may happen as part of the expression [index]= value, where the space is not allowed and causes the shell to interpret it as [index]="" [index+1]=value.
If you wanted the element to have a value, remove the spaces after =, e.g. [index]=value.
If you wanted to assign an empty string, explicitly use empty quotes: [index]="". This makes no difference to the shell, but will make your intention clear to shellcheck and other humans.
Example of incorrect code:
array=([1]=one [2]= two)Example of correct code:
array=([1]=one [2]=two)