impl pg array append

diesel/src/pg/expression/expression_methods.rs

@@ -2730,10 +2730,16 @@ pub(in crate::pg) mod private {
         message = "`{Self}` is neither `diesel::sql_types::Array<_>` nor `diesel::sql_types::Nullable<Array<_>>`",
         note = "try to provide an expression that produces one of the expected sql types"
     )]
-    pub trait ArrayOrNullableArray {}
+    pub trait ArrayOrNullableArray {
+        type Inner;
+    }
 
-    impl<T> ArrayOrNullableArray for Array<T> {}
-    impl<T> ArrayOrNullableArray for Nullable<Array<T>> {}
+    impl<T> ArrayOrNullableArray for Array<T> {
+        type Inner = T;
+    }
+    impl<T> ArrayOrNullableArray for Nullable<Array<T>> {
+        type Inner = T;
+    }
 
     /// Marker trait used to implement `PgNetExpressionMethods` on the appropriate types.
     #[diagnostic::on_unimplemented(

diesel/src/pg/expression/functions.rs

@@ -3,6 +3,7 @@
 use super::expression_methods::InetOrCidr;
 use super::expression_methods::RangeHelper;
 use crate::expression::functions::define_sql_function;
+use crate::pg::expression::expression_methods::ArrayOrNullableArray;
 use crate::sql_types::*;
 
 define_sql_function! {
@@ -687,3 +688,28 @@ define_sql_function! {
     #[cfg(feature = "postgres_backend")]
     fn daterange(lower: Nullable<Date>, upper: Nullable<Date>, bound: RangeBoundEnum) -> Daterange;
 }
+
+#[cfg(feature = "postgres_backend")]
+define_sql_function! {
+    /// Append an element to the end of an array.
+    /// # Example
+    ///
+    /// ```rust
+    /// # include!("../../doctest_setup.rs");
+    /// #
+    /// # fn main() {
+    /// #     run_test().unwrap();
+    /// # }
+    /// #
+    /// # fn run_test() -> QueryResult<()> {
+    /// #     use diesel::dsl::array_append;
+    /// #     use diesel::sql_types::{Integer, Array};
+    /// #     let connection = &mut establish_connection();
+    /// let ints = diesel::select(array_append::<Integer, Array<_>, _, _>(vec![1, 2], 3))
+    ///     .get_result::<Vec<i32>>(connection)?;
+    /// assert_eq!(vec![1, 2, 3], ints);
+    /// #     Ok(())
+    /// # }
+    /// ```
+    fn array_append<T: SingleValue, Arr: ArrayOrNullableArray<Inner=T> + SingleValue>(a: Arr, e: T) -> Array<T>;
+}

diesel/src/serialize.rs

@@ -237,7 +237,7 @@ where
 ///        match *self {
 ///            // these string values need to match the labels used in your
 ///            // enum definition in SQL. So this expects that you defined the
-///            /// relevat enum type as`ENUM('one', 'two')` in your `CREATE TABLE` statement
+///            /// relevant enum type as`ENUM('one', 'two')` in your `CREATE TABLE` statement
 ///            Post::FirstValue => out.write_all(b"one")?,
 ///            Post::SecondValue => out.write_all(b"two")?,
 ///        }