Remove with_string_cache

crates/polars-core/src/chunked_array/logical/categorical/string_cache.rs

@@ -94,21 +94,13 @@ pub fn enable_string_cache() {
 ///
 /// **Warning**: Disabling the string cache this way may cause errors if there
 /// are other threads that rely the global string cache being enabled.
-/// Consider using either [`with_string_cache`] or [`StringCacheHolder`] for a
-/// more reliable way of enabling and disabling the string cache.
+/// Consider using [`StringCacheHolder`] for a more reliable way of enabling
+/// and disabling the string cache.
 pub fn disable_string_cache() {
     USE_STRING_CACHE.store(0, Ordering::Release);
     STRING_CACHE.clear()
 }
 
-/// Execute a function with the global string cache enabled.
-pub fn with_string_cache<F: FnOnce() -> T, T>(func: F) -> T {
-    set_string_cache(true);
-    let out = func();
-    set_string_cache(false);
-    out
-}
-
 /// Check whether the global string cache is enabled.
 pub fn using_string_cache() -> bool {
     USE_STRING_CACHE.load(Ordering::Acquire) > 0

crates/polars/tests/it/lazy/predicate_queries.rs

@@ -1,6 +1,6 @@
 // used only if feature="is_in", feature="dtype-categorical"
 #[allow(unused_imports)]
-use polars_core::{with_string_cache, SINGLE_LOCK};
+use polars_core::{StringCacheHolder, SINGLE_LOCK};
 
 use super::*;
 
@@ -132,24 +132,22 @@ fn test_is_in_categorical_3420() -> PolarsResult<()> {
     ]?;
 
     let _guard = SINGLE_LOCK.lock();
+    disable_string_cache();
+    let _sc = StringCacheHolder::hold();
 
-    let _: PolarsResult<_> = with_string_cache(|| {
-        let s = Series::new("x", ["a", "b", "c"]).strict_cast(&DataType::Categorical(None))?;
-        let out = df
-            .lazy()
-            .with_column(col("a").strict_cast(DataType::Categorical(None)))
-            .filter(col("a").is_in(lit(s).alias("x")))
-            .collect()?;
-
-        let mut expected = df![
-            "a" => ["a", "b", "c"],
-            "b" => [1, 2, 3]
-        ]?;
-        expected.try_apply("a", |s| s.cast(&DataType::Categorical(None)))?;
-        assert!(out.frame_equal(&expected));
+    let s = Series::new("x", ["a", "b", "c"]).strict_cast(&DataType::Categorical(None))?;
+    let out = df
+        .lazy()
+        .with_column(col("a").strict_cast(DataType::Categorical(None)))
+        .filter(col("a").is_in(lit(s).alias("x")))
+        .collect()?;
 
-        Ok(())
-    });
+    let mut expected = df![
+        "a" => ["a", "b", "c"],
+        "b" => [1, 2, 3]
+    ]?;
+    expected.try_apply("a", |s| s.cast(&DataType::Categorical(None)))?;
+    assert!(out.frame_equal(&expected));
     Ok(())
 }