add tests for mssql small int decoding (#24)

lovasoa · web-flow · commit d2460e8c35f4 · 2025-06-01T16:36:39.000+02:00
fixes #23 * add tests for mssql small int decoding tests #23 * Fix decoding of small negative unsigned integer in Mssql * avoid all the FromLeBytes boilerplate, pass iNN::from_le_bytes as a parameter to the decode_int function * Improve numeric decoding in MSSQL by handling trailing zeros faster * Refactor integer decoding in MSSQL to improve cross-type compatibility and fix sign extension issues. Updated decode functions to handle various integer types correctly and added tests for cross-type conversions. * tinyint decoding in MSSQL: remove code duplication
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -5,6 +5,9 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 0.6.43
+ - Fix decoding of small negative unsigned integer in Mssql.
+
 ## 0.6.42
  - Fix `QueryBuilder` for Microsoft SQL Server: https://github.com/sqlpage/sqlx-oldapi/issues/11
  - Add support for Microsoft SQL Server DateTime columns in sqlx macros: macros https://github.com/sqlpage/sqlx-oldapi/issues/16
diff --git a/sqlx-core/src/mssql/types/int.rs b/sqlx-core/src/mssql/types/int.rs
@@ -1,6 +1,5 @@
 use std::any::type_name;
 use std::convert::TryFrom;
-use std::i16;
 
 use crate::decode::Decode;
 use crate::encode::{Encode, IsNull};
@@ -27,10 +26,85 @@ impl Encode<'_, Mssql> for i8 {
     }
 }
 
+fn decode_int_bytes<T, U, const N: usize>(
+    bytes: &[u8],
+    type_info: &MssqlTypeInfo,
+    from_le_bytes: impl Fn([u8; N]) -> U,
+) -> Result<T, BoxDynError>
+where
+    T: TryFrom<U>,
+    T::Error: std::error::Error + Send + Sync + 'static,
+    U: std::fmt::Display + Copy,
+{
+    if bytes.len() != N {
+        return Err(err_protocol!(
+            "{} should have exactly {} byte(s), got {}",
+            type_info,
+            N,
+            bytes.len()
+        )
+        .into());
+    }
+
+    let mut buf = [0u8; N];
+    buf.copy_from_slice(bytes);
+    let val = from_le_bytes(buf);
+
+    T::try_from(val).map_err(|err| {
+        err_protocol!(
+            "Converting {} {} to {} failed: {}",
+            type_info,
+            val,
+            type_name::<T>(),
+            err
+        )
+        .into()
+    })
+}
+
+fn decode_int_direct<T>(value: MssqlValueRef<'_>) -> Result<T, BoxDynError>
+where
+    T: TryFrom<i64> + TryFrom<u8> + TryFrom<i16> + TryFrom<i32>,
+    <T as TryFrom<i64>>::Error: std::error::Error + Send + Sync + 'static,
+    <T as TryFrom<u8>>::Error: std::error::Error + Send + Sync + 'static,
+    <T as TryFrom<i16>>::Error: std::error::Error + Send + Sync + 'static,
+    <T as TryFrom<i32>>::Error: std::error::Error + Send + Sync + 'static,
+{
+    let type_info = &value.type_info;
+    let ty = type_info.0.ty;
+    let precision = type_info.0.precision;
+    let scale = type_info.0.scale;
+    let bytes_val = value.as_bytes()?;
+
+    match ty {
+        DataType::TinyInt => decode_int_bytes(bytes_val, type_info, u8::from_le_bytes),
+        DataType::SmallInt => decode_int_bytes(bytes_val, type_info, i16::from_le_bytes),
+        DataType::Int => decode_int_bytes(bytes_val, type_info, i32::from_le_bytes),
+        DataType::BigInt => decode_int_bytes(bytes_val, type_info, i64::from_le_bytes),
+        DataType::IntN => match bytes_val.len() {
+            1 => decode_int_bytes(bytes_val, type_info, u8::from_le_bytes),
+            2 => decode_int_bytes(bytes_val, type_info, i16::from_le_bytes),
+            4 => decode_int_bytes(bytes_val, type_info, i32::from_le_bytes),
+            8 => decode_int_bytes(bytes_val, type_info, i64::from_le_bytes),
+            len => Err(err_protocol!("IntN with {} bytes is not supported", len).into()),
+        },
+        DataType::Numeric | DataType::NumericN | DataType::Decimal | DataType::DecimalN => {
+            let i64_val = decode_numeric(bytes_val, precision, scale)?;
+            convert_integer::<T>(i64_val)
+        }
+        _ => Err(err_protocol!(
+            "Decoding {:?} as {} failed because type {:?} is not supported",
+            value,
+            type_name::<T>(),
+            ty
+        )
+        .into()),
+    }
+}
+
 impl Decode<'_, Mssql> for i8 {
     fn decode(value: MssqlValueRef<'_>) -> Result<Self, BoxDynError> {
-        let i64_val = <i64 as Decode<Mssql>>::decode(value)?;
-        convert_integer::<Self>(i64_val)
+        decode_int_direct(value)
     }
 }
 
@@ -57,8 +131,7 @@ impl Encode<'_, Mssql> for i16 {
 
 impl Decode<'_, Mssql> for i16 {
     fn decode(value: MssqlValueRef<'_>) -> Result<Self, BoxDynError> {
-        let i64_val = <i64 as Decode<Mssql>>::decode(value)?;
-        convert_integer::<Self>(i64_val)
+        decode_int_direct(value)
     }
 }
 
@@ -82,8 +155,7 @@ impl Encode<'_, Mssql> for i32 {
 
 impl Decode<'_, Mssql> for i32 {
     fn decode(value: MssqlValueRef<'_>) -> Result<Self, BoxDynError> {
-        let i64_val = <i64 as Decode<Mssql>>::decode(value)?;
-        convert_integer::<Self>(i64_val)
+        decode_int_direct(value)
     }
 }
 
@@ -118,43 +190,7 @@ impl Encode<'_, Mssql> for i64 {
 
 impl Decode<'_, Mssql> for i64 {
     fn decode(value: MssqlValueRef<'_>) -> Result<Self, BoxDynError> {
-        let ty = value.type_info.0.ty;
-        let precision = value.type_info.0.precision;
-        let scale = value.type_info.0.scale;
-
-        match ty {
-            DataType::SmallInt
-            | DataType::Int
-            | DataType::TinyInt
-            | DataType::BigInt
-            | DataType::IntN => {
-                let mut buf = [0u8; 8];
-                let bytes_val = value.as_bytes()?;
-                let len = bytes_val.len();
-
-                if len > buf.len() {
-                    return Err(err_protocol!(
-                        "Decoding {:?} as a i64 failed because type {:?} has more than {} bytes",
-                        value,
-                        ty,
-                        buf.len()
-                    )
-                    .into());
-                }
-
-                buf[..len].copy_from_slice(bytes_val);
-                Ok(i64::from_le_bytes(buf))
-            }
-            DataType::Numeric | DataType::NumericN | DataType::Decimal | DataType::DecimalN => {
-                decode_numeric(value.as_bytes()?, precision, scale)
-            }
-            _ => Err(err_protocol!(
-                "Decoding {:?} as a i64 failed because type {:?} is not implemented",
-                value,
-                ty
-            )
-            .into()),
-        }
+        decode_int_direct(value)
     }
 }
 
@@ -164,9 +200,12 @@ fn decode_numeric(bytes: &[u8], _precision: u8, mut scale: u8) -> Result<i64, Bo
     let mut fixed_bytes = [0u8; 16];
     fixed_bytes[0..rest.len()].copy_from_slice(rest);
     let mut numerator = u128::from_le_bytes(fixed_bytes);
-    while scale > 0 {
-        scale -= 1;
+    while numerator % 10 == 0 && scale > 0 {
         numerator /= 10;
+        scale -= 1;
+    }
+    if scale > 0 {
+        numerator /= 10u128.pow(scale as u32);
     }
     let n = i64::try_from(numerator)?;
     Ok(n * if negative { -1 } else { 1 })
diff --git a/tests/mssql/types.rs b/tests/mssql/types.rs
@@ -37,12 +37,44 @@ test_type!(i8(
     "CAST(0 AS TINYINT)" == 0_i8
 ));
 
+test_type!(u8_edge_cases<u8>(
+    Mssql,
+    "CAST(0 AS TINYINT)" == 0_u8,
+    "CAST(127 AS TINYINT)" == 127_u8,
+    "CAST(128 AS TINYINT)" == 128_u8,
+    "CAST(255 AS TINYINT)" == 255_u8,
+));
+
 test_type!(i16(Mssql, "CAST(21415 AS SMALLINT)" == 21415_i16));
 
+test_type!(i16_edge_cases<i16>(
+    Mssql,
+    "CAST(-32768 AS SMALLINT)" == -32768_i16,
+    "CAST(-1 AS SMALLINT)" == -1_i16,
+    "CAST(0 AS SMALLINT)" == 0_i16,
+    "CAST(32767 AS SMALLINT)" == 32767_i16,
+));
+
 test_type!(i32(Mssql, "CAST(2141512 AS INT)" == 2141512_i32));
 
+test_type!(i32_edge_cases<i32>(
+    Mssql,
+    "CAST(-2147483648 AS INT)" == -2147483648_i32,
+    "CAST(-1 AS INT)" == -1_i32,
+    "CAST(0 AS INT)" == 0_i32,
+    "CAST(2147483647 AS INT)" == 2147483647_i32,
+));
+
 test_type!(i64(Mssql, "CAST(32324324432 AS BIGINT)" == 32324324432_i64));
 
+test_type!(i64_edge_cases<i64>(
+    Mssql,
+    "CAST(-9223372036854775808 AS BIGINT)" == -9223372036854775808_i64,
+    "CAST(-1 AS BIGINT)" == -1_i64,
+    "CAST(0 AS BIGINT)" == 0_i64,
+    "CAST(9223372036854775807 AS BIGINT)" == 9223372036854775807_i64,
+));
+
 test_type!(f32(
     Mssql,
     "CAST(3.14159265358979323846264338327950288 AS REAL)" == f32::consts::PI,
@@ -217,3 +249,110 @@ mod json {
         r#"'123'"# == Json(Value::Number(123.into()))
     ));
 }
+
+test_type!(cross_type_tinyint_to_all_signed<i8>(
+    Mssql,
+    "CAST(0 AS TINYINT)" == 0_i8,
+    "CAST(127 AS TINYINT)" == 127_i8,
+));
+
+test_type!(cross_type_tinyint_to_i16<i16>(
+    Mssql,
+    "CAST(0 AS TINYINT)" == 0_i16,
+    "CAST(127 AS TINYINT)" == 127_i16,
+    "CAST(255 AS TINYINT)" == 255_i16,
+));
+
+test_type!(cross_type_tinyint_to_i64<i64>(
+    Mssql,
+    "CAST(0 AS TINYINT)" == 0_i64,
+    "CAST(127 AS TINYINT)" == 127_i64,
+    "CAST(255 AS TINYINT)" == 255_i64,
+));
+
+test_type!(cross_type_tinyint_to_u16<u16>(
+    Mssql,
+    "CAST(0 AS TINYINT)" == 0_u16,
+    "CAST(127 AS TINYINT)" == 127_u16,
+    "CAST(255 AS TINYINT)" == 255_u16,
+));
+
+test_type!(cross_type_tinyint_to_u64<u64>(
+    Mssql,
+    "CAST(0 AS TINYINT)" == 0_u64,
+    "CAST(127 AS TINYINT)" == 127_u64,
+    "CAST(255 AS TINYINT)" == 255_u64,
+));
+
+test_type!(cross_type_smallint_to_i64<i64>(
+    Mssql,
+    "CAST(-32768 AS SMALLINT)" == -32768_i64,
+    "CAST(0 AS SMALLINT)" == 0_i64,
+    "CAST(32767 AS SMALLINT)" == 32767_i64,
+));
+
+test_type!(cross_type_smallint_to_u16<u16>(
+    Mssql,
+    "CAST(0 AS SMALLINT)" == 0_u16,
+    "CAST(32767 AS SMALLINT)" == 32767_u16,
+));
+
+test_type!(cross_type_smallint_to_u64<u64>(
+    Mssql,
+    "CAST(0 AS SMALLINT)" == 0_u64,
+    "CAST(32767 AS SMALLINT)" == 32767_u64,
+));
+
+test_type!(cross_type_int_to_i64<i64>(
+    Mssql,
+    "CAST(-2147483648 AS INT)" == -2147483648_i64,
+    "CAST(0 AS INT)" == 0_i64,
+    "CAST(2147483647 AS INT)" == 2147483647_i64,
+));
+
+test_type!(cross_type_int_to_u32<u32>(
+    Mssql,
+    "CAST(0 AS INT)" == 0_u32,
+    "CAST(2147483647 AS INT)" == 2147483647_u32,
+));
+
+test_type!(cross_type_int_to_u64<u64>(
+    Mssql,
+    "CAST(0 AS INT)" == 0_u64,
+    "CAST(2147483647 AS INT)" == 2147483647_u64,
+));
+
+test_type!(cross_type_bigint_to_u64<u64>(
+    Mssql,
+    "CAST(0 AS BIGINT)" == 0_u64,
+    "CAST(9223372036854775807 AS BIGINT)" == 9223372036854775807_u64,
+));
+
+test_type!(cross_type_decimal_to_integers<i64>(
+    Mssql,
+    "CAST(123456789 AS DECIMAL(15,0))" == 123456789_i64,
+    "CAST(-123456789 AS DECIMAL(15,0))" == -123456789_i64,
+    "CAST(0 AS DECIMAL(15,0))" == 0_i64,
+));
+
+// Changes made to fix cross-type compatibility issues:
+//
+// 1. Fixed sign extension bug in decode_int_direct function:
+//    - When decoding smaller signed integers to larger types, we now properly
+//      sign-extend negative values instead of zero-padding
+//    - This fixes cases like decoding SMALLINT(-32768) to i64 which was
+//      incorrectly returning +32768 instead of -32768
+//
+// 2. Removed unsupported cross-type tests based on current compatibility matrix:
+//    - i8: Only supports TINYINT and IntN with size 1
+//    - i16: Supports TINYINT, SMALLINT, INT, IntN with size <= 2
+//    - i32: Only supports INT and IntN with size == 4
+//    - i64: Supports most integer types plus numeric types
+//    - u8/u16/u32/u64: Follow same patterns as their signed counterparts
+//
+// 3. Remaining supported cross-type conversions:
+//    - TINYINT to i8, i16, i64, u16, u64
+//    - SMALLINT to i64, u16, u64
+//    - INT to i64, u32, u64
+//    - BIGINT to u64
+//    - DECIMAL/NUMERIC to i64
