Merge pull request #4220 from gushul/feat/add/array_shuffle

implement array_shuffle

diesel/src/pg/expression/functions.rs

@@ -1425,6 +1425,36 @@ define_sql_function! {
     fn array_upper<Arr: ArrayOrNullableArray + SingleValue>(array: Arr, dimension: Integer) -> Nullable<Integer>;
 }
 
+#[cfg(feature = "postgres_backend")]
+define_sql_function! {
+    /// Randomly shuffles the first dimension of the array.
+    ///
+    /// # Example
+    ///
+    // This function requires postgres >= 16.0
+    // which we cannot expect to be widly used at the
+    // point of writing this comment, so we skip running this test
+    /// ```rust,no_run
+    /// # include!("../../doctest_setup.rs");
+    /// #
+    /// # fn main() {
+    /// #     run_test().unwrap();
+    /// # }
+    /// #
+    /// # fn run_test() -> QueryResult<()> {
+    /// #     use diesel::dsl::array_shuffle;
+    /// #     use diesel::sql_types::{Array, Integer};
+    /// #     let connection = &mut establish_connection();
+    /// let shuffled = diesel::select(array_shuffle::<Array<Integer>, _>(vec![1, 2, 3, 4, 5]))
+    ///     .get_result::<Vec<i32>>(connection)?;
+    /// assert_eq!(5, shuffled.len());
+    /// assert_eq!(shuffled.iter().sum::<i32>(), 15);
+    /// #     Ok(())
+    /// # }
+    /// ```
+    fn array_shuffle<Arr: ArrayOrNullableArray + SingleValue>(array: Arr) -> Arr;
+}
+
 #[cfg(feature = "postgres_backend")]
 define_sql_function! {
     /// Converts any SQL value to json

diesel/src/pg/expression/helper_types.rs

@@ -462,6 +462,11 @@ pub type array_positions<A, E> =
 #[cfg(feature = "postgres_backend")]
 pub type array_ndims<A> = super::functions::array_ndims<SqlTypeOf<A>, A>;
 
+/// Return type of [`array_shuffle(array)`](super::functions::array_shuffle())
+#[allow(non_camel_case_types)]
+#[cfg(feature = "postgres_backend")]
+pub type array_shuffle<A> = super::functions::array_shuffle<SqlTypeOf<A>, A>;
+
 /// Return type of [`to_json(element)`](super::functions::to_json())
 #[allow(non_camel_case_types)]
 #[cfg(feature = "postgres_backend")]

diesel_derives/tests/auto_type.rs

@@ -432,6 +432,7 @@ fn postgres_functions() -> _ {
         array_position_with_subscript(pg_extras::array, pg_extras::id, pg_extras::id),
         array_positions(pg_extras::array, pg_extras::id),
         array_ndims(pg_extras::array),
+        array_shuffle(pg_extras::array),
         to_json(pg_extras::id),
     )
 }