chore: Fix clippy

Author: comphead

Cargo.toml

@@ -212,6 +212,9 @@ needless_pass_by_value = "warn"
 # https://github.com/apache/datafusion/issues/18881
 allow_attributes = "warn"
 assigning_clones = "warn"
+# ScalarValue and Expr contain Arc<..> with interior mutability but are
+# intentionally used as hash keys throughout the codebase.
+mutable_key_type = "allow"
 
 [workspace.lints.rust]
 unexpected_cfgs = { level = "warn", check-cfg = [

datafusion-cli/tests/cli_integration.rs

@@ -414,14 +414,12 @@ fn test_backtrace_output(#[case] query: &str) {
     let output = cmd.output().expect("Failed to execute command");
     let stdout = String::from_utf8_lossy(&output.stdout);
     let stderr = String::from_utf8_lossy(&output.stderr);
-    let combined_output = format!("{}{}", stdout, stderr);
+    let combined_output = format!("{stdout}{stderr}");
 
     // Assert that the output includes literal 'backtrace'
     assert!(
         combined_output.to_lowercase().contains("backtrace"),
-        "Expected output to contain 'backtrace', but got stdout: '{}' stderr: '{}'",
-        stdout,
-        stderr
+        "Expected output to contain 'backtrace', but got stdout: '{stdout}' stderr: '{stderr}'"
     );
 }
 

datafusion/common/src/error.rs

@@ -1274,7 +1274,6 @@ mod test {
     // To pass the test the environment variable RUST_BACKTRACE should be set to 1 to enforce backtrace
     #[cfg(feature = "backtrace")]
     #[test]
-    #[expect(clippy::unnecessary_literal_unwrap)]
     fn test_enabled_backtrace() {
         match std::env::var("RUST_BACKTRACE") {
             Ok(val) if val == "1" => {}

datafusion/common/src/hash_utils.rs

@@ -19,12 +19,15 @@
 
 use arrow::array::types::{IntervalDayTime, IntervalMonthDayNano};
 use arrow::array::*;
+#[cfg(not(feature = "force_hash_collisions"))]
 use arrow::compute::take;
 use arrow::datatypes::*;
 #[cfg(not(feature = "force_hash_collisions"))]
 use arrow::{downcast_dictionary_array, downcast_primitive_array};
 use foldhash::fast::FixedState;
+#[cfg(not(feature = "force_hash_collisions"))]
 use itertools::Itertools;
+#[cfg(not(feature = "force_hash_collisions"))]
 use std::collections::HashMap;
 use std::hash::{BuildHasher, Hash, Hasher};
 
@@ -198,6 +201,7 @@ hash_float_value!((half::f16, u16), (f32, u32), (f64, u64));
 /// Create a `SeedableRandomState` whose per-hasher seed incorporates `seed`.
 /// This folds the previous hash into the hasher's initial state so only the
 /// new value needs to pass through the hash function — same cost as `hash_one`.
+#[cfg(not(feature = "force_hash_collisions"))]
 #[inline]
 fn seeded_state(seed: u64) -> foldhash::fast::SeedableRandomState {
     foldhash::fast::SeedableRandomState::with_seed(
@@ -303,6 +307,7 @@ fn hash_array<T>(
 /// HAS_NULLS: do we have to check null in the inner loop
 /// HAS_BUFFERS: if true, array has external buffers; if false, all strings are inlined/ less then 12 bytes
 /// REHASH: if true, combining with existing hash, otherwise initializing
+#[cfg(not(feature = "force_hash_collisions"))]
 #[inline(never)]
 fn hash_string_view_array_inner<
     T: ByteViewType,
@@ -429,6 +434,7 @@ fn hash_generic_byte_view_array<T: ByteViewType>(
 /// - `HAS_NULL_KEYS`: Whether to check for null dictionary keys
 /// - `HAS_NULL_VALUES`: Whether to check for null dictionary values
 /// - `MULTI_COL`: Whether to combine with existing hash (true) or initialize (false)
+#[cfg(not(feature = "force_hash_collisions"))]
 #[inline(never)]
 fn hash_dictionary_inner<
     K: ArrowDictionaryKeyType,

datafusion/execution/src/memory_pool/arrow.rs

@@ -59,7 +59,7 @@ impl arrow_buffer::MemoryReservation for MemoryReservation {
 impl arrow_buffer::MemoryPool for ArrowMemoryPool {
     fn reserve(&self, size: usize) -> Box<dyn arrow_buffer::MemoryReservation> {
         let consumer = self.consumer.clone_with_new_id();
-        let mut reservation = consumer.register(&self.inner);
+        let reservation = consumer.register(&self.inner);
         reservation.grow(size);
 
         Box::new(reservation)

datafusion/physical-plan/src/aggregates/group_values/single_group_by/primitive.rs

@@ -28,6 +28,7 @@ use datafusion_execution::memory_pool::proxy::VecAllocExt;
 use datafusion_expr::EmitTo;
 use half::f16;
 use hashbrown::hash_table::HashTable;
+#[cfg(not(feature = "force_hash_collisions"))]
 use std::hash::BuildHasher;
 use std::mem::size_of;
 use std::sync::Arc;