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authorVincent Ambo <mail@tazj.in>2022-10-04T15·40+0300
committertazjin <tazjin@tvl.su>2022-10-05T13·07+0000
commit7fe1331570918e9eae2a9868497afba7f61ad742 (patch)
tree68e2b7f82bdc60c9a3e2f2855b90c94994320712 /tvix/eval
parent8f2c67d5dd9fabc007fdf4e15dd1dfaf829de38f (diff)
feat(tvix/eval): implement tvix's user-agent, err, nixVersion r/5038
nixpkgs has hardcoded references to Nix versions, we need to provide
it with something that looks like a Nix version while actually being a
Tvix version.

For now, we do this by stealing a trick out of the browser book and
constructing a version that looks like a Nix version to Nix, but like
a Tvix version to people who know what they are looking for.

Nevermind that we don't actually have any kind of versioning for
Tvix (yet?), other than depot revisions.

Change-Id: I7ce8079dd8164a2079891d38e707f09a45f0bbc1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6858
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Diffstat (limited to 'tvix/eval')
-rw-r--r--tvix/eval/src/builtins/mod.rs6
-rw-r--r--tvix/eval/src/tests/tvix_tests/eval-okay-nix-version-cmp.exp1
-rw-r--r--tvix/eval/src/tests/tvix_tests/eval-okay-nix-version-cmp.nix5
3 files changed, 12 insertions, 0 deletions
diff --git a/tvix/eval/src/builtins/mod.rs b/tvix/eval/src/builtins/mod.rs
index 848ac9e25dca..61ff60fa059c 100644
--- a/tvix/eval/src/builtins/mod.rs
+++ b/tvix/eval/src/builtins/mod.rs
@@ -374,6 +374,12 @@ fn pure_builtins() -> Vec<Builtin> {
 fn builtins_set() -> NixAttrs {
     let mut map: BTreeMap<NixString, Value> = BTreeMap::new();
 
+    // Pure-value builtins
+    map.insert(
+        "nixVersion".into(),
+        Value::String("2.3-compat-tvix-0.1".into()),
+    );
+
     let mut add_builtins = |builtins: Vec<Builtin>| {
         for builtin in builtins {
             map.insert(builtin.name().into(), Value::Builtin(builtin));
diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-nix-version-cmp.exp b/tvix/eval/src/tests/tvix_tests/eval-okay-nix-version-cmp.exp
new file mode 100644
index 000000000000..3a2e3f4984a0
--- /dev/null
+++ b/tvix/eval/src/tests/tvix_tests/eval-okay-nix-version-cmp.exp
@@ -0,0 +1 @@
+-1
diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-nix-version-cmp.nix b/tvix/eval/src/tests/tvix_tests/eval-okay-nix-version-cmp.nix
new file mode 100644
index 000000000000..6f353056127c
--- /dev/null
+++ b/tvix/eval/src/tests/tvix_tests/eval-okay-nix-version-cmp.nix
@@ -0,0 +1,5 @@
+# nixpkgs checks against the `builtins.nixVersion` and fails if it
+# doesn't like what it sees. To work around this we have a "user-agent
+# style" version (see cl/6858) that ensures compatibility.
+
+builtins.compareVersions "2.3" builtins.nixVersion