fix: Return correct python package version

crates/polars-python/src/c_api/mod.rs

@@ -1,6 +1,10 @@
 #[cfg(feature = "allocator")]
 pub mod allocator;
 
+// Since Python Polars cannot share its version into here and we need to be able to build this
+// package correctly without `py-polars`, we need to mirror the version here.
+pub static PYPOLARS_VERSION: &str = "1.32.1";
+
 use pyo3::prelude::*;
 use pyo3::{wrap_pyfunction, wrap_pymodule};
 
@@ -414,7 +418,7 @@ pub fn polars(py: Python, m: &Bound<PyModule>) -> PyResult<()> {
         .unwrap();
 
     // Build info
-    m.add("__version__", env!("CARGO_PKG_VERSION"))?;
+    m.add("__version__", PYPOLARS_VERSION)?;
 
     // Plugins
     #[cfg(feature = "ffi_plugin")]

py-polars/src/lib.rs

@@ -1 +1,23 @@
+const fn _const_str_equality(l: &str, r: &str) -> bool {
+    if l.len() != r.len() {
+        return false;
+    }
+
+    let mut i = 0;
+    while i < l.len() {
+        if l.as_bytes()[i] != r.as_bytes()[i] {
+            return false;
+        }
+        i += 1;
+    }
+
+    true
+}
+const _CORRECT_VERSION_SET: () = const {
+    let module_version = polars_python::c_api::PYPOLARS_VERSION;
+    let package_version = env!("CARGO_PKG_VERSION");
+
+    // You probably need to update the PYPOLARS_VERSION, to match the package version.
+    assert!(_const_str_equality(module_version, package_version));
+};
 pub use polars_python::c_api::polars;

py-polars/tests/unit/test_init.py

@@ -1,3 +1,5 @@
+import importlib
+
 import pytest
 
 import polars as pl
@@ -41,3 +43,8 @@ def test_type_aliases_deprecated() -> None:
 
 def test_import_all() -> None:
     exec("from polars import *")
+
+
+def test_version() -> None:
+    # This has already gone wrong once (#23940), preventing future problems.
+    assert pl.__version__ == importlib.metadata.version("polars")