On Sunday, 15 December 2024 at 08:45:22 UTC, DLearner wrote:
Please consider:
```
size_t foo() {
static size_t var1 = 1;
var1 = var1 + 1;
return var1;
}
unittest {
assert(foo() == 2);
assert(foo() == 3);
}
```
which works as expected.
But
```
size_t foo1() {
static size_t var1 = 1;
var1 = var1 + 1;
return var1;
}
unittest {
assert(foo1() == 2);
}
unittest {
assert(foo1() == 2);
}
```
Fails on the second unittest.
I appreciate this behaviour matches the docs (so not a bug),
but is it desirable?
Yes. Remember that you have the function attribute `pure` [[1]].
It would have avoided the problem.. for instance:
```d
size_t foo1() {
static size_t var1 = 1;
var1 = var1 + 1;
return var1;
}
pure unittest {
assert(foo1() == 2);
}
pure unittest {
assert(foo1() == 2);
}
```
refuses to compile with the following errors
test.d(9,15): Error: `pure` function
`temp_7F58D0140210.__unittest_L8_C6` cannot call impure
function `temp_7F58D0140210.foo1`
test.d(13,15): Error: `pure` function
`temp_7F58D0140210.__unittest_L12_C6` cannot call impure
function `temp_7F58D0140210.foo1`
With `pure` that you would have seen the problem, that is "oh,
the global state".
[1]: https://dlang.org/spec/function.html#pure-functions
