lix/doc/manual/rl-next/nixversion-fake.md

---
synopsis: "`builtins.nixVersion` and `builtins.langVersion` return fixed values"
cls: [558, 1144]
credits: jade
category: Breaking Changes
---

`builtins.nixVersion` now returns a fixed value `"2.18.3-lix"`.

`builtins.langVersion` returns a fixed value `6`, matching CppNix 2.18.

This prevents feature detection assuming that features that exist in Nix
post-Lix-branch-off might exist, even though the Lix version is greater than
the Nix version.

In the future, check for builtins for feature detection. If a feature cannot be
detected by *those* means, please file a Lix bug.
Release notes for builtins.nixVersion change Change-Id: I72c945cab464d26d73f5594ef0a4bb2184545da4 2024-03-19 01:26:52 +00:00			`---`
builtins: fix builtins.langVersion docs to state it's deprecated This builtin was always a problem and nixpkgs uses it in exactly one place, to give up if the Nix version is absurdly old. It has no other use cases, and doesn't work in a multi-implementation world anyway. Change-Id: I03c36e118591029e2ef14b091fe14a311c66a08a 2024-05-16 04:40:39 +00:00			synopsis: "`builtins.nixVersion` and `builtins.langVersion` return fixed values"
			`cls: [558, 1144]`
doc: add release note credits and categories for all the changes in Lix This does not add missing release notes, and it doesn't do anything about the profiles feature we would really like to have so we can have consistent credit. Change-Id: I72a6f7acfcff85f380be17dac76501a6f4693776 2024-05-15 02:14:58 +00:00			`credits: jade`
			`category: Breaking Changes`
Release notes for builtins.nixVersion change Change-Id: I72c945cab464d26d73f5594ef0a4bb2184545da4 2024-03-19 01:26:52 +00:00			`---`

builtins: fix builtins.langVersion docs to state it's deprecated This builtin was always a problem and nixpkgs uses it in exactly one place, to give up if the Nix version is absurdly old. It has no other use cases, and doesn't work in a multi-implementation world anyway. Change-Id: I03c36e118591029e2ef14b091fe14a311c66a08a 2024-05-16 04:40:39 +00:00			`builtins.nixVersion` now returns a fixed value `"2.18.3-lix"`.

			`builtins.langVersion` returns a fixed value `6`, matching CppNix 2.18.

			`This prevents feature detection assuming that features that exist in Nix`
			`post-Lix-branch-off might exist, even though the Lix version is greater than`
			`the Nix version.`
Release notes for builtins.nixVersion change Change-Id: I72c945cab464d26d73f5594ef0a4bb2184545da4 2024-03-19 01:26:52 +00:00
			`In the future, check for builtins for feature detection. If a feature cannot be`
			`detected by those means, please file a Lix bug.`