Interpolation of integers

[sergeygrigorev]

Assume this config:

# config
a = 1
b = 2
c = "$a + $a = $b"
# spec
a = integer
b = integer
c = string

It finds that c matches with Template regex, tries to substitute a into c, finds a and tries to match Template regex with a that is integer because of spec applied. So, it raises TypeError: expected string or bytes-like object.

[hanschen]

Sounds like a duplicate of #129.

[jhermann]

Related to #129, not a duplicate. It's the exact inverse.

[WeatherGod]

Actually, I suspect this is exactly the same issue. The problem is that the configspec turned the values into non-strings. But the string interpolation stage only supports string-like inputs and does no coercion at all.

In fact, you don't even need a configspec to cause this problem:

foo = 1, 2, 3
bar = This list: ${foo}

is sufficient to cause the issue if list_values=True.

I want to fix this problem for a work project. I don't think the right thing to do is to perform coercion. Rather, perhaps the original strings could be stored along side the stored values and those values are used for string interpolation instead. Maybe fall back to using str() on the value in the case where there is no stored string representation (such as when the configobj didn't come from a string buffer or the user sets a non-string value after construction).

[robdennis]

optimistically putting this in 5.1.0 assuming that the referenced PR helps me understand what's being requested