Fix deserialization of empty PostgreSQL ranges

In diesel empty ranges are represented as: ``` ( Bound::Excluded(T::default()), Bound::Excluded(T::default()), ) ```
diesel-rs · Oct 4, 2024 · 2b97dd1 · 2b97dd1
1 parent 381be19
commit 2b97dd1
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Showing 4 changed files with 47 additions and 7 deletions.
diff --git a/diesel/src/pg/types/floats/mod.rs b/diesel/src/pg/types/floats/mod.rs
@@ -9,7 +9,7 @@ use std::error::Error;
 #[cfg(feature = "quickcheck")]
 mod quickcheck_impls;
 
-#[derive(Debug, Clone, PartialEq, Eq, AsExpression, FromSqlRow)]
+#[derive(Default, Debug, Clone, PartialEq, Eq, AsExpression, FromSqlRow)]
 #[diesel(sql_type = sql_types::Numeric)]
 /// Represents a NUMERIC value, closely mirroring the PG wire protocol
 /// representation
@@ -33,6 +33,7 @@ pub enum PgNumeric {
         digits: Vec<i16>,
     },
     /// Not a number
+    #[default]
     NaN,
 }
 

diff --git a/diesel/src/pg/types/multirange.rs b/diesel/src/pg/types/multirange.rs
@@ -68,7 +68,7 @@ multirange_as_expressions!(std::ops::RangeTo<T>);
 #[cfg(feature = "postgres_backend")]
 impl<T, ST> FromSql<Multirange<ST>, Pg> for Vec<(Bound<T>, Bound<T>)>
 where
-    T: FromSql<ST, Pg>,
+    T: FromSql<ST, Pg> + std::default::Default,
 {
     fn from_sql(value: PgValue<'_>) -> deserialize::Result<Self> {
         let mut bytes = value.as_bytes();

diff --git a/diesel/src/pg/types/ranges.rs b/diesel/src/pg/types/ranges.rs
@@ -74,15 +74,17 @@ range_as_expression!(&'a std::ops::RangeTo<T>; Nullable<Range<ST>>);
 #[cfg(feature = "postgres_backend")]
 impl<T, ST> FromSql<Range<ST>, Pg> for (Bound<T>, Bound<T>)
 where
-    T: FromSql<ST, Pg>,
+    T: FromSql<ST, Pg> + std::default::Default,
 {
     fn from_sql(value: PgValue<'_>) -> deserialize::Result<Self> {
         let mut bytes = value.as_bytes();
         let flags: RangeFlags = RangeFlags::from_bits_truncate(bytes.read_u8()?);
         let mut lower_bound = Bound::Unbounded;
         let mut upper_bound = Bound::Unbounded;
 
-        if !flags.contains(RangeFlags::LB_INF) {
+        if flags.contains(RangeFlags::EMPTY) {
+            lower_bound = Bound::Excluded(T::default());
+        } else if !flags.contains(RangeFlags::LB_INF) {
             let elem_size = bytes.read_i32::<NetworkEndian>()?;
             let (elem_bytes, new_bytes) = bytes.split_at(elem_size.try_into()?);
             bytes = new_bytes;
@@ -95,7 +97,9 @@ where
             };
         }
 
-        if !flags.contains(RangeFlags::UB_INF) {
+        if flags.contains(RangeFlags::EMPTY) {
+            upper_bound = Bound::Excluded(T::default());
+        } else if !flags.contains(RangeFlags::UB_INF) {
             let _size = bytes.read_i32::<NetworkEndian>()?;
             let value = T::from_sql(PgValue::new_internal(bytes, &value))?;
 
@@ -113,7 +117,7 @@ where
 #[cfg(feature = "postgres_backend")]
 impl<T, ST> Queryable<Range<ST>, Pg> for (Bound<T>, Bound<T>)
 where
-    T: FromSql<ST, Pg>,
+    T: FromSql<ST, Pg> + std::default::Default,
 {
     type Row = Self;
 

diff --git a/diesel_tests/tests/types.rs b/diesel_tests/tests/types.rs
@@ -1422,10 +1422,45 @@ fn test_range_from_sql() {
         query_single_value::<Range<Int4>, (Bound<i32>, Bound<i32>)>(query)
     );
 
-    let query = "SELECT '(1,1]'::int4range";
+    let query = "SELECT '[2,1)'::int4range";
     assert!(sql::<Range<Int4>>(query)
         .load::<(Bound<i32>, Bound<i32>)>(connection)
         .is_err());
+
+    let query = "'empty'::int4range";
+    let expected_value = (Bound::Excluded(0), Bound::Excluded(0));
+    assert_eq!(
+        expected_value,
+        query_single_value::<Range<Int4>, (Bound<i32>, Bound<i32>)>(query)
+    );
+
+    let query = "SELECT '(1,1)'::int4range";
+    let expected_value = (Bound::Excluded(0), Bound::Excluded(0));
+    assert_eq!(
+        expected_value,
+        query_single_value::<Range<Int4>, (Bound<i32>, Bound<i32>)>(query)
+    );
+
+    let query = "SELECT '(1,1]'::int4range";
+    let expected_value = (Bound::Excluded(0), Bound::Excluded(0));
+    assert_eq!(
+        expected_value,
+        query_single_value::<Range<Int4>, (Bound<i32>, Bound<i32>)>(query)
+    );
+
+    let query = "SELECT '[1,1)'::int4range";
+    let expected_value = (Bound::Excluded(0), Bound::Excluded(0));
+    assert_eq!(
+        expected_value,
+        query_single_value::<Range<Int4>, (Bound<i32>, Bound<i32>)>(query)
+    );
+
+    let query = "SELECT '[1,1]'::int4range";
+    let expected_value = (Bound::Included(1), Bound::Included(1));
+    assert_eq!(
+        expected_value,
+        query_single_value::<Range<Int4>, (Bound<i32>, Bound<i32>)>(query)
+    );
 }
 
 #[cfg(feature = "postgres")]