From 22480afeb513ee457ed89de84349798e9f287e80 Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Wed, 7 Jan 2026 09:20:01 +0100
Subject: [PATCH] EvalStateBuilder: Specify Nix version constraint

---
 Cargo.lock                          | 94 ++++++++++++++++-------------
 nix-bindings-expr/Cargo.toml        |  5 ++
 nix-bindings-expr/build.rs          |  6 ++
 nix-bindings-expr/src/eval_state.rs |  5 ++
 4 files changed, 68 insertions(+), 42 deletions(-)
 create mode 100644 nix-bindings-expr/build.rs

diff --git a/Cargo.lock b/Cargo.lock
index e4a8151..821630f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4,9 +4,9 @@ version = 4
 
 [[package]]
 name = "aho-corasick"
-version = "1.1.4"
+version = "1.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ddd31a130427c27518df266943a5308ed92d4b226cc639f5a8f1002816174301"
+checksum = "8e60d3430d3a69478ad0993f19238d2df97c507009a52b3c10addcd7f6bcb916"
 dependencies = [
  "memchr",
 ]
@@ -42,9 +42,9 @@ dependencies = [
 
 [[package]]
 name = "bitflags"
-version = "2.10.0"
+version = "2.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "812e12b5285cc515a9c72a5c1d3b6d46a19dac5acfef5265968c166106e31dd3"
+checksum = "2261d10cca569e4643e526d8dc2e62e433cc8aba21ab764233731f8d369bf394"
 
 [[package]]
 name = "cexpr"
@@ -57,9 +57,9 @@ dependencies = [
 
 [[package]]
 name = "cfg-if"
-version = "1.0.4"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
+checksum = "2fd1289c04a9ea8cb22300a459a72a385d7c73d3259e2ed7dcb2af674838cfa9"
 
 [[package]]
 name = "clang-sys"
@@ -105,7 +105,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
 dependencies = [
  "libc",
- "windows-sys 0.61.2",
+ "windows-sys 0.61.1",
 ]
 
 [[package]]
@@ -116,14 +116,14 @@ checksum = "37909eebbb50d72f9059c3b6d82c0463f2ff062c9e95845c43a6c9c0355411be"
 
 [[package]]
 name = "getrandom"
-version = "0.3.4"
+version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "899def5c37c4fd7b2664648c28120ecec138e4d395b459e5ca34f9cce2dd77fd"
+checksum = "26145e563e54f2cadc477553f1ec5ee650b00862f0a58bcd12cbdc5f0ea2d2f4"
 dependencies = [
  "cfg-if",
  "libc",
  "r-efi",
- "wasip2",
+ "wasi",
 ]
 
 [[package]]
@@ -134,11 +134,11 @@ checksum = "0cc23270f6e1808e30a928bdc84dea0b9b4136a8bc82338574f23baf47bbd280"
 
 [[package]]
 name = "home"
-version = "0.5.12"
+version = "0.5.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cc627f471c528ff0c4a49e1d5e60450c8f6461dd6d10ba9dcd3a61d3dff7728d"
+checksum = "589533453244b0995c858700322199b2becb13b627df2851f64a2775d024abcf"
 dependencies = [
- "windows-sys 0.61.2",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -164,9 +164,9 @@ checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
 
 [[package]]
 name = "libc"
-version = "0.2.180"
+version = "0.2.176"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bcc35a38544a891a5f7c865aca548a982ccb3b8650a5b06d0fd33a10283c56fc"
+checksum = "58f929b4d672ea937a23a1ab494143d968337a5f47e56d0815df1e0890ddf174"
 
 [[package]]
 name = "libloading"
@@ -192,9 +192,9 @@ checksum = "df1d3c3b53da64cf5760482273a98e575c651a67eec7f77df96b5b642de8f039"
 
 [[package]]
 name = "log"
-version = "0.4.29"
+version = "0.4.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5e5032e24019045c762d3c0f28f5b6b8bbf38563a65908389bf7978758920897"
+checksum = "34080505efa8e45a4b816c349525ebe327ceaa8559756f0356cba97ef3bf7432"
 
 [[package]]
 name = "memchr"
@@ -219,6 +219,7 @@ dependencies = [
  "nix-bindings-store",
  "nix-bindings-util",
  "nix-bindings-util-sys",
+ "pkg-config",
  "tempfile",
 ]
 
@@ -315,18 +316,18 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.105"
+version = "1.0.101"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "535d180e0ecab6268a3e718bb9fd44db66bbbc256257165fc699dadf70d16fe7"
+checksum = "89ae43fd86e4158d6db51ad8e2b80f313af9cc74f5c0e03ccb87de09998732de"
 dependencies = [
  "unicode-ident",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.43"
+version = "1.0.41"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc74d9a594b72ae6656596548f56f667211f8a97b3d4c3d467150794690dc40a"
+checksum = "ce25767e7b499d1b604768e7cde645d14cc8584231ea6b295e9c9eb22c02e1d1"
 dependencies = [
  "proc-macro2",
 ]
@@ -339,9 +340,9 @@ checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"
 
 [[package]]
 name = "regex"
-version = "1.12.2"
+version = "1.11.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "843bc0191f75f3e22651ae5f1e72939ab2f72a4bc30fa80a066bd66edefc24d4"
+checksum = "8b5288124840bee7b386bc413c487869b360b2b4ec421ea56425128692f2a82c"
 dependencies = [
  "aho-corasick",
  "memchr",
@@ -351,9 +352,9 @@ dependencies = [
 
 [[package]]
 name = "regex-automata"
-version = "0.4.13"
+version = "0.4.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5276caf25ac86c8d810222b3dbb938e512c55c6831a10f3e6ed1c93b84041f1c"
+checksum = "833eb9ce86d40ef33cb1306d8accf7bc8ec2bfea4355cbdebb3df68b40925cad"
 dependencies = [
  "aho-corasick",
  "memchr",
@@ -362,9 +363,9 @@ dependencies = [
 
 [[package]]
 name = "regex-syntax"
-version = "0.8.8"
+version = "0.8.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7a2d987857b319362043e95f5353c0535c1f58eec5336fdfcf626430af7def58"
+checksum = "caf4aa5b0f434c91fe5c7f1ecb6a5ece2130b02ad2a590589dda5146df959001"
 
 [[package]]
 name = "rustc-hash"
@@ -387,15 +388,15 @@ dependencies = [
 
 [[package]]
 name = "rustix"
-version = "1.1.3"
+version = "1.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "146c9e247ccc180c1f61615433868c99f3de3ae256a30a43b49f67c2d9171f34"
+checksum = "cd15f8a2c5551a84d56efdc1cd049089e409ac19a3072d5037a17fd70719ff3e"
 dependencies = [
  "bitflags",
  "errno",
  "libc",
  "linux-raw-sys 0.11.0",
- "windows-sys 0.61.2",
+ "windows-sys 0.61.1",
 ]
 
 [[package]]
@@ -406,9 +407,9 @@ checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
 
 [[package]]
 name = "syn"
-version = "2.0.114"
+version = "2.0.106"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d4d107df263a3013ef9b1879b0df87d706ff80f65a86ea879bd9c31f9b307c2a"
+checksum = "ede7c438028d4436d71104916910f5bb611972c5cfd7f89b8300a8186e6fada6"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -417,22 +418,31 @@ dependencies = [
 
 [[package]]
 name = "tempfile"
-version = "3.24.0"
+version = "3.23.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "655da9c7eb6305c55742045d5a8d2037996d61d8de95806335c7c86ce0f82e9c"
+checksum = "2d31c77bdf42a745371d260a26ca7163f1e0924b64afa0b688e61b5a9fa02f16"
 dependencies = [
  "fastrand",
  "getrandom",
  "once_cell",
- "rustix 1.1.3",
- "windows-sys 0.61.2",
+ "rustix 1.1.2",
+ "windows-sys 0.61.1",
 ]
 
 [[package]]
 name = "unicode-ident"
-version = "1.0.22"
+version = "1.0.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9312f7c4f6ff9069b165498234ce8be658059c6728633667c526e27dc2cf1df5"
+checksum = "f63a545481291138910575129486daeaf8ac54aee4387fe7906919f7830c7d9d"
+
+[[package]]
+name = "wasi"
+version = "0.14.7+wasi-0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "883478de20367e224c0090af9cf5f9fa85bed63a95c1abf3afc5c083ebc06e8c"
+dependencies = [
+ "wasip2",
+]
 
 [[package]]
 name = "wasip2"
@@ -457,9 +467,9 @@ dependencies = [
 
 [[package]]
 name = "windows-link"
-version = "0.2.1"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
+checksum = "45e46c0661abb7180e7b9c281db115305d49ca1709ab8242adf09666d2173c65"
 
 [[package]]
 name = "windows-sys"
@@ -472,9 +482,9 @@ dependencies = [
 
 [[package]]
 name = "windows-sys"
-version = "0.61.2"
+version = "0.61.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
+checksum = "6f109e41dd4a3c848907eb83d5a42ea98b3769495597450cf6d153507b166f0f"
 dependencies = [
  "windows-link",
 ]
diff --git a/nix-bindings-expr/Cargo.toml b/nix-bindings-expr/Cargo.toml
index 41b3cc7..e931946 100644
--- a/nix-bindings-expr/Cargo.toml
+++ b/nix-bindings-expr/Cargo.toml
@@ -2,6 +2,7 @@
 name = "nix-bindings-expr"
 version = "0.1.0"
 edition = "2021"
+build = "build.rs"
 license = "LGPL-2.1"
 description = "Rust bindings to Nix expression evaluator"
 repository = "https://github.com/nixops4/nix-bindings-rust"
@@ -19,6 +20,10 @@ ctor = "0.2"
 tempfile = "3.10"
 cstr = "0.2"
 
+[build-dependencies]
+pkg-config = "0.3"
+nix-bindings-util = { path = "../nix-bindings-util" }
+
 [lints.rust]
 warnings = "deny"
 dead-code = "allow"
diff --git a/nix-bindings-expr/build.rs b/nix-bindings-expr/build.rs
new file mode 100644
index 0000000..6a038bd
--- /dev/null
+++ b/nix-bindings-expr/build.rs
@@ -0,0 +1,6 @@
+use nix_bindings_util::nix_version::emit_version_cfg;
+
+fn main() {
+    let nix_version = pkg_config::probe_library("nix-expr-c").unwrap().version;
+    emit_version_cfg(&nix_version, &["2.26"]);
+}
diff --git a/nix-bindings-expr/src/eval_state.rs b/nix-bindings-expr/src/eval_state.rs
index f2e5b29..70d2ae0 100644
--- a/nix-bindings-expr/src/eval_state.rs
+++ b/nix-bindings-expr/src/eval_state.rs
@@ -224,6 +224,8 @@ impl Drop for EvalStateRef {
 /// Provides advanced configuration options for evaluation context setup.
 /// Use [`EvalState::new`] for simple cases or this builder for custom configuration.
 ///
+/// Requires Nix 2.26.0 or later.
+///
 /// # Examples
 ///
 /// ```rust
@@ -244,11 +246,13 @@ impl Drop for EvalStateRef {
 /// # Ok(())
 /// # }
 /// ```
+#[cfg(nix_at_least = "2.26")]
 pub struct EvalStateBuilder {
     eval_state_builder: *mut raw::eval_state_builder,
     lookup_path: Vec<CString>,
     store: Store,
 }
+#[cfg(nix_at_least = "2.26")]
 impl Drop for EvalStateBuilder {
     fn drop(&mut self) {
         unsafe {
@@ -256,6 +260,7 @@ impl Drop for EvalStateBuilder {
         }
     }
 }
+#[cfg(nix_at_least = "2.26")]
 impl EvalStateBuilder {
     /// Creates a new [`EvalStateBuilder`].
     pub fn new(store: Store) -> Result<EvalStateBuilder> {