fix(psl): validate partial index raw predicate arity

Signed-off-by: Alexey Orlenko's AI Agent <robot@aqrln.net>

Author: tensordreams

psl/parser-database/src/attributes.rs

@@ -640,16 +640,16 @@ fn parse_where_clause(model_id: crate::ModelId, ctx: &mut Context<'_>) -> Option
 
 /// Parse raw("...") where clause.
 fn parse_raw_where_clause(args: &[ast::Argument], ctx: &mut Context<'_>) -> Option<WhereClause> {
-    let Some(first_arg) = args.first() else {
+    let [arg] = args else {
         ctx.push_attribute_validation_error(
-            "The `where` argument must be a raw() function with a string argument, e.g. `where: raw(\"status = 'active'\")`.",
+            "The `where` argument must be a raw() function with exactly one string argument, e.g. `where: raw(\"status = 'active'\")`.",
         );
         return None;
     };
 
-    let Some(predicate) = coerce::string(&first_arg.value, ctx.diagnostics) else {
+    let Some(predicate) = coerce::string(&arg.value, ctx.diagnostics) else {
         ctx.push_attribute_validation_error(
-            "The `where` argument must be a raw() function with a string argument, e.g. `where: raw(\"status = 'active'\")`.",
+            "The `where` argument must be a raw() function with exactly one string argument, e.g. `where: raw(\"status = 'active'\")`.",
         );
         return None;
     };

psl/psl/tests/attributes/partial_index.rs

@@ -166,7 +166,7 @@ fn partial_index_raw_requires_string_argument() {
 
     let err = parse_unwrap_err(&with_header(dml, Provider::Postgres, &["partialIndexes"]));
     let expected = expect![[r#"
-        [1;91merror[0m: [1mError parsing attribute "@unique": The `where` argument must be a raw() function with a string argument, e.g. `where: raw("status = 'active'")`.[0m
+        [1;91merror[0m: [1mError parsing attribute "@unique": The `where` argument must be a raw() function with exactly one string argument, e.g. `where: raw("status = 'active'")`.[0m
           -->  schema.prisma:15
            | 
         14 | 
@@ -176,6 +176,30 @@ fn partial_index_raw_requires_string_argument() {
     expected.assert_eq(&err);
 }
 
+#[test]
+fn partial_index_raw_rejects_multiple_arguments() {
+    let dml = indoc! {r#"
+        model User {
+            id        Int    @id
+            email     String
+            status    String
+
+            @@unique([email], where: raw("status = 'active'", "email IS NOT NULL"))
+        }
+    "#};
+
+    let err = parse_unwrap_err(&with_header(dml, Provider::Postgres, &["partialIndexes"]));
+    let expected = expect![[r#"
+        error: Error parsing attribute "@unique": The `where` argument must be a raw() function with exactly one string argument, e.g. `where: raw("status = 'active'")`.
+          -->  schema.prisma:15
+           | 
+        14 | 
+        15 |     @@unique([email], where: raw("status = 'active'", "email IS NOT NULL"))
+           | 
+    "#]];
+    expected.assert_eq(&err);
+}
+
 #[test]
 fn partial_index_cannot_have_empty_predicate() {
     let dml = indoc! {r#"