Repository: tursodatabase/limbo (rust)

Issue:
Incorrect conversion of text type to integer type with unary `+`
Found with #1116. In Limbo, `SELECT +'000'` incorrectly converts the text into a integer returning `0`. But in Sqlite3, `+` becomes is a noop and leaves the string as is.

Fuzzing found this case:

```cmd
assertion `left == right` failed: with expression Output { query: "+ ((?) || (?))", parameters: [Integer(0), Integer(0)], depth: 2 }
  left: Text(Text { value: [48, 48], subtype: Text })
 right: Integer(0)
```

Pull request description:
Unary `+` is a noop
Fixes #1154.

Unary `+` is a noop in Sqlite: <https://sqlite.org/lang_expr.html#operators_and_parse_affecting_attributes>.

Patch:
diff --git a/core/translate/expr.rs b/core/translate/expr.rs
index 9e003ba3..a214613d 100644
--- a/core/translate/expr.rs
+++ b/core/translate/expr.rs
@@ -2040,19 +2040,14 @@ pub fn translate_expr(
         ast::Expr::Raise(_, _) => todo!(),
         ast::Expr::Subquery(_) => todo!(),
         ast::Expr::Unary(op, expr) => match (op, expr.as_ref()) {
-            (
-                UnaryOperator::Negative | UnaryOperator::Positive,
-                ast::Expr::Literal(ast::Literal::Numeric(numeric_value)),
-            ) => {
-                let multiplier = if let UnaryOperator::Negative = op {
-                    -1
-                } else {
-                    1
-                };
-
+            (UnaryOperator::Positive, expr) => {
+                translate_expr(program, referenced_tables, expr, target_register, resolver)
+            }
+            (UnaryOperator::Negative, ast::Expr::Literal(ast::Literal::Numeric(numeric_value))) => {
                 // Special case: if we're negating "9223372036854775808", this is exactly MIN_INT64
-                // If we don't do this -1 * 9223372036854775808 will overflow and parse will fail and trigger conversion to Real.
-                if multiplier == -1 && numeric_value == "9223372036854775808" {
+                // If we don't do this -1 * 9223372036854775808 will overflow and parse will fail
+                // and trigger conversion to Real.
+                if numeric_value == "9223372036854775808" {
                     program.emit_insn(Insn::Integer {
                         value: i64::MIN,
                         dest: target_register,
@@ -2061,25 +2056,21 @@ pub fn translate_expr(
                     let maybe_int = numeric_value.parse::<i64>();
                     if let Ok(value) = maybe_int {
                         program.emit_insn(Insn::Integer {
-                            value: value * multiplier,
+                            value: value * -1,
                             dest: target_register,
                         });
                     } else {
                         let value = numeric_value.parse::<f64>()?;
                         program.emit_insn(Insn::Real {
-                            value: value * multiplier as f64,
+                            value: value * -1 as f64,
                             dest: target_register,
                         });
                     }
                 }
                 Ok(target_register)
             }
-            (UnaryOperator::Negative | UnaryOperator::Positive, _) => {
-                let value = if let UnaryOperator::Negative = op {
-                    -1
-                } else {
-                    1
-                };
+            (UnaryOperator::Negative, _) => {
+                let value = -1;
 
                 let reg = program.alloc_register();
                 translate_expr(program, referenced_tables, expr, reg, resolver)?;


Test patch:
diff --git a/testing/math.test b/testing/math.test
index 847f94f9..e014483b 100755
--- a/testing/math.test
+++ b/testing/math.test
@@ -1383,4 +1383,12 @@ do_execsql_test comp-blog-string {
 
 do_execsql_test comp-blog-blog {
     SELECT cast('0' as BLOB) = cast('0' as BLOB)
-} { 1 }
\ No newline at end of file
+} { 1 }
+
+do_execsql_test unary-plus-noop-string {
+    SELECT +'000'
+} { 000 }
+
+do_execsql_test unary-plus-noop-blob {
+    SELECT typeof(+x'00') = 'blob'
+} { 1 }