| --- | |
| title: 'Error: Variable x is read only' | |
| --- | |
| A global variable cannot be reassigned. It will always point to the same object. | |
| However, its content might change, if the value is mutable (for example, the | |
| content of a list). Local variables don't have this restriction. | |
| ```python | |
| a = [1, 2] | |
| a[1] = 3 | |
| b = 3 | |
| b = 4 # forbidden | |
| ``` | |
| `ERROR: /path/ext.bzl:7:1: Variable b is read only` | |
| You will get a similar error if you try to redefine a function (function | |
| overloading is not supported), for example: | |
| ```python | |
| def foo(x): return x + 1 | |
| def foo(x, y): return x + y # forbidden | |
| ``` |