MGS SpIdentifier slot could be a u16 #8490
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jgallagher
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Jul 1, 2025
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Weird way to describe it, but: this was a very satisfying PR to review. 👍
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Depends on #8398 and takes the next step of change the SpIdentifier slot to a u16 instead of a u32. In some discussions, including with @rmustacc, we decided that it would be very surprising to ever have more than u16::MAX slots in a single rack, but conceivable that we could exceed u8::MAX in some future device. (In practice, we have ways to evolve all these APIs so this doesn't really foreclose on anything and we probably could get away with
u8::MAX.I did do this mechanically but the changes weren't all as straightforward as with #8398. For example, there's a separate
SpIdentifierthat used ausize, and it was previously converted from a location map that was loaded in via serde. I figured serde would barf if the u16 was out of range so we could just make the structure contain a u16 directly. I also removed two error cases in code paths that already wanted to store slots as u16s (and changed one that already assumed it was a u8!).