1d0 = 1

I feel like this should be 0. And I really want it to be 0, so that I can use the die type as a variable in my Savage Worlds macros. ie, Since the weapon damage is a die type, like d4 or d6, I'd like to be able to put in 0 for no weapon and get out no damage.

if you tell it 0d0 it gives you a 0.... are you trying to set up macros that call the dice type from an attribute, or are you doing it some other way?

Yes. Using the Fantasy Companion rules where weapons can do Str+d8 or Str+d4 damage, and Str is always a die type, I have this for damage:

Rolled [[{1d@{selected|Weapon}+1d@{selected|Strength}}]] vs @{target|Toughness}

Then I was hoping to just put in the character's Weapon as a value (0, 4, 6, 8, 10, 12) and Strength as a similar value.

a d0 should always result in a zero value. I agree with Rendelle F. It shouldn't matter how many times you roll the die of impossibility, because it will still be an outcome of impossible (or zero in this case).

I agree, 1d0 should be 0. It's not gonna come up often except in macros like this and then people usually want a 0 I guess

What you could try to do is create a few rollable table, for each dice size. Add 1,2,3,4, etc to it (leave Weight at 1). Name it d4 and d6 etc. Also create a d0 which only returns a 0.

Now call [[{1t[d@{selected|Weapon}]+1d@{selected|Strength}}]] vs @{target|Toughness}

That should do the trick.

if you want to be able to set Strength to 0 as well: [[{1t[d@{selected|Weapon}]+1t[d@{selected|Strength}]}]] vs @{target|Toughness}

why not just put the entire dice expression in the selected attribute instead of the number of sides?
[[{@{selected|Weapon}+@{selected|Strength}}]] vs @{target|Toughness}
@{selected|Weapon}= 0d0 or whatever the die is
@{selected|Strength}= 1d6 or whatever the die you want to roll is...
it works.... It doesn't change the fact that 1d0=1 for roll20, but you just use 0d whatever and get exactly what you are looking for.

Quatar's solution should work, but Roger's is very simple. It would also allow me have, for example, 2d6 or 1d12+2 (the latter of which I was planning to think about when or if it came up, since it's a thing that only very high-level characters can have). Side note: rather than using 0d0 for no weapon, I should just be able to use 0.

Thanks to both of you!

Moving this to the Bug Report forum since this is a bug. I have filed a bug report with the Devs.

This should be fixed in the next update.