feat(psl): Validation error when shadowDatabaseUrl is identical to url or directUrl

psl/diagnostics/src/error.rs

@@ -332,8 +332,13 @@ impl DatamodelError {
         Self::new(format!("Datasource provider not known: \"{provider}\"."), span)
     }
 
-    pub fn new_shadow_database_is_same_as_main_url_error(source_name: String, span: Span) -> DatamodelError {
-        let msg = format!("shadowDatabaseUrl is the same as url for datasource \"{source_name}\". Please specify a different database as shadow database.");
+    pub fn new_shadow_database_is_same_as_main_url_error(source_name: &str, span: Span) -> DatamodelError {
+        let msg = format!("shadowDatabaseUrl is the same as url for datasource \"{source_name}\". Please specify a different database as shadow database to avoid data loss.");
+        Self::new(msg, span)
+    }
+
+    pub fn new_shadow_database_is_same_as_direct_url_error(source_name: &str, span: Span) -> DatamodelError {
+        let msg = format!("shadowDatabaseUrl is the same as directUrl for datasource \"{source_name}\". Please specify a different database as shadow database to avoid data loss.");
         Self::new(msg, span)
     }
 

psl/psl-core/src/validate/datasource_loader.rs

@@ -163,6 +163,24 @@ fn lift_datasource(
         None => (None, None),
     };
 
+    if let Some((shadow_url, _)) = &shadow_database_url {
+        if let (Some(direct_url), Some(direct_url_span)) = (&direct_url, direct_url_span) {
+            if shadow_url == direct_url {
+                diagnostics.push_error(DatamodelError::new_shadow_database_is_same_as_direct_url_error(
+                    source_name,
+                    direct_url_span,
+                ));
+            }
+        }
+
+        if shadow_url == &url {
+            diagnostics.push_error(DatamodelError::new_shadow_database_is_same_as_main_url_error(
+                source_name,
+                url_span,
+            ));
+        }
+    }
+
     preview_features_guardrail(&mut args, diagnostics);
 
     let documentation = ast_source.documentation().map(String::from);

psl/psl/tests/validation/datasource/direct_url_same_as_shadow.prisma

@@ -0,0 +1,19 @@
+datasource testds {
+    provider = "mysql"
+    url = "mysql://testurl"
+    directUrl = "mysql://testurl"
+    shadowDatabaseUrl = "mysql://testurl"
+}
+
+// error: shadowDatabaseUrl is the same as directUrl for datasource "testds". Please specify a different database as shadow database to avoid data loss.
+//   -->  schema.prisma:4
+//    | 
+//  3 |     url = "mysql://testurl"
+//  4 |     directUrl = "mysql://testurl"
+//    | 
+// error: shadowDatabaseUrl is the same as url for datasource "testds". Please specify a different database as shadow database to avoid data loss.
+//   -->  schema.prisma:3
+//    | 
+//  2 |     provider = "mysql"
+//  3 |     url = "mysql://testurl"
+//    | 

psl/psl/tests/validation/datasource/url_same_as_shadow.prisma

@@ -0,0 +1,12 @@
+datasource testds {
+    provider = "mysql"
+    url = "mysql://testurl"
+    shadowDatabaseUrl = "mysql://testurl"
+}
+
+// error: shadowDatabaseUrl is the same as url for datasource "testds". Please specify a different database as shadow database to avoid data loss.
+//   -->  schema.prisma:3
+//    | 
+//  2 |     provider = "mysql"
+//  3 |     url = "mysql://testurl"
+//    |