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Diffstat (limited to 'tvix/eval/src/builtins/versions.rs')
-rw-r--r-- | tvix/eval/src/builtins/versions.rs | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/tvix/eval/src/builtins/versions.rs b/tvix/eval/src/builtins/versions.rs index ee75eeaeed3b..e149cc4dba37 100644 --- a/tvix/eval/src/builtins/versions.rs +++ b/tvix/eval/src/builtins/versions.rs @@ -1,4 +1,5 @@ use std::cmp::Ordering; +use std::iter::{once, Chain, Once}; use std::ops::RangeInclusive; /// Version strings can be broken up into Parts. @@ -69,6 +70,20 @@ impl<'a> VersionPartsIter<'a> { version, } } + + /// Create an iterator that yields all version parts followed by an additional + /// `VersionPart::Word("")` part (i.e. you can think of this as + /// `builtins.splitVersion version ++ [ "" ]`). This is necessary, because + /// Nix's `compareVersions` is not entirely lexicographical: If we have two + /// equal versions, but one is longer, the longer one is only considered + /// greater if the first additional part of the longer version is not `pre`, + /// e.g. `2.3 > 2.3pre`. It is otherwise lexicographical, so peculiar behavior + /// like `2.3 < 2.3.0pre` ensues. Luckily for us, this means that we can + /// lexicographically compare two version strings, _if_ we append an extra + /// component to both versions. + pub fn new_for_cmp(version: &'a str) -> Chain<Self, Once<VersionPart>> { + Self::new(version).chain(once(VersionPart::Word(""))) + } } impl<'a> Iterator for VersionPartsIter<'a> { |