tzif: support pathological transitions #164
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It turns out that some TZif files seem to have "pathological" transitions that are very far in the past. So far, in fact, that they are outside the supported range of Jiff's `Timestamp` (that is, `-9999-01-01` to `9999-12-31`). This in turn caused parsing such TZif files to fail. But they are technically valid TZif files. There's nothing that says, e.g., `i64::MIN` is an illegal transition value. So we support them here by simply clamping out-of-range time zone transitions to Jiff's range. While this could in theory be invalid for some possible TZif files, they would need to be specifically constructed to be invalid. In practice, there are no DST rules at the boundaries of what Jiff supports, so this should be fine. Fixes #163
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I have no idea what's going on here. But WASM tests are currently [failing on CI] with an unscrutable error. What's worse is that I cannot reproduce it locally. Sigh. So for now, we rollback the Rust toolchain to an older version. I suppose this is just kicking the can down the road, but it follows in the footsteps of numbat (which Jiff's WASM tests were inspired by). I found Rust 1.81 by just going backwards from the current release (1.83). [failing on CI]: https://github.com/BurntSushi/jiff/actions/runs/12097259497/job/33732443120?pr=164 [footsteps of `numbat`]: https://github.com/sharkdp/numbat/pull/563/files
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This PR also fixed CI. For WASM, I kicked the can down the road and pinned Rust to 1.81. I have no idea what newer versions are failing. It doesn't fail for me locally. |
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This PR is on crates.io in |
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It turns out that some TZif files seem to have "pathological"
transitions that are very far in the past. So far, in fact, that they
are outside the supported range of Jiff's
Timestamp(that is,-9999-01-01to9999-12-31). This in turn caused parsing such TZiffiles to fail.
But they are technically valid TZif files. There's nothing that says,
e.g.,
i64::MINis an illegal transition value.So we support them here by simply clamping out-of-range time zone
transitions to Jiff's range. While this could in theory be invalid for
some possible TZif files, they would need to be specifically constructed
to be invalid. In practice, there are no DST rules at the boundaries of
what Jiff supports, so this should be fine.
Fixes #163