fix: cast BigInt values to text in JSON aggregation for MySQL/Cockroach (prisma#5752)

polaz · dimsssss · commit 5b107d3e769f · 2026-02-26T23:08:00.000+09:00
Closes prisma#5751. ## Summary - Cast MySQL BigInt/UnsignedBigInt values to CHAR in JSON_OBJECT to preserve precision in JS JSON parsing. - Extend Postgres visitor to also cast Cockroach INT8/Int8 to text in JSONB_BUILD_OBJECT. - Add visitor tests for both cases.
diff --git a/quaint/src/visitor/mysql.rs b/quaint/src/visitor/mysql.rs
@@ -121,6 +121,16 @@ impl<'a> Mysql<'a> {
                     })?;
                     Ok(())
                 }
+                // Convert BigInt to string to preserve precision when parsed by JavaScript.
+                (Some(TypeFamily::Int), Some("BIGINT" | "UNSIGNEDBIGINT")) => {
+                    self.write("CONVERT")?;
+                    self.surround_with("(", ")", |s| {
+                        s.visit_expression(expr)?;
+                        s.write(", ")?;
+                        s.write("CHAR")
+                    })?;
+                    Ok(())
+                }
                 _ => self.visit_expression(expr),
             },
             _ => self.visit_expression(expr),
@@ -717,6 +727,7 @@ fn get_target_table<'a>(query: &Query<'a>) -> Option<Table<'a>> {
 
 #[cfg(test)]
 mod tests {
+    use crate::ast::*;
     use crate::visitor::*;
 
     fn expected_values<'a, T>(sql: &'static str, params: Vec<T>) -> (String, Vec<Value<'a>>)
@@ -816,6 +827,36 @@ mod tests {
         );
     }
 
+    #[test]
+    fn json_build_object_casts_bigint_to_string() {
+        let build_json = json_build_object(vec![(
+            "id".into(),
+            Column::from("id")
+                .native_column_type(Some("BIGINT"))
+                .type_family(TypeFamily::Int)
+                .into(),
+        )]);
+        let query = Select::default().value(build_json);
+        let (sql, _) = Mysql::build(query).unwrap();
+
+        assert_eq!("SELECT JSON_OBJECT('id', CONVERT(`id`, CHAR))", sql);
+    }
+
+    #[test]
+    fn json_build_object_casts_unsigned_bigint_to_string() {
+        let build_json = json_build_object(vec![(
+            "id".into(),
+            Column::from("id")
+                .native_column_type(Some("UNSIGNEDBIGINT"))
+                .type_family(TypeFamily::Int)
+                .into(),
+        )]);
+        let query = Select::default().value(build_json);
+        let (sql, _) = Mysql::build(query).unwrap();
+
+        assert_eq!("SELECT JSON_OBJECT('id', CONVERT(`id`, CHAR))", sql);
+    }
+
     #[test]
     fn equality_with_a_json_value() {
         let expected = expected_values(
diff --git a/quaint/src/visitor/postgres.rs b/quaint/src/visitor/postgres.rs
@@ -33,7 +33,7 @@ impl<'a> Postgres<'a> {
                 }
                 // Cast BigInt to text to preserve precision when parsed by JavaScript.
                 // JavaScript's JSON.parse loses precision for integers > 2^53-1.
-                (Some(TypeFamily::Int), Some("BIGINT")) => {
+                (Some(TypeFamily::Int), Some("BIGINT" | "INT8")) => {
                     self.visit_expression(expr)?;
                     self.write("::text")?;
 
@@ -1425,6 +1425,20 @@ mod tests {
             assert_eq!(sql, "SELECT JSONB_BUILD_OBJECT('id', \"id\"::text)");
         }
 
+        #[test]
+        fn int8() {
+            let build_json = json_build_object(vec![(
+                "id".into(),
+                Column::from("id")
+                    .native_column_type(Some("INT8"))
+                    .type_family(TypeFamily::Int)
+                    .into(),
+            )]);
+            let query = Select::default().value(build_json);
+            let (sql, _) = Postgres::build(query).unwrap();
+
+            assert_eq!(sql, "SELECT JSONB_BUILD_OBJECT('id', \"id\"::text)");
+        }
         fn build_json_object(num_fields: u32) -> JsonBuildObject<'static> {
             let fields = (1..=num_fields)
                 .map(|i| (format!("f{i}").into(), Expression::from(i as i64)))
