Add local-only columns

Author: simolus3

crates/core/src/schema/common.rs

@@ -1,6 +1,7 @@
 use core::slice;
 
 use alloc::{string::String, vec::Vec};
+use serde::Deserialize;
 
 use crate::schema::{
     Column, CommonTableOptions, RawTable, Table, raw_table::InferredTableStructure,
@@ -61,6 +62,7 @@ impl<'a> Iterator for SchemaTableColumnIterator<'a> {
     }
 }
 
+#[derive(Default)]
 pub struct ColumnFilter {
     sorted_names: Vec<String>,
 }
@@ -82,3 +84,18 @@ impl ColumnFilter {
             .is_ok()
     }
 }
+
+impl AsRef<Vec<String>> for ColumnFilter {
+    fn as_ref(&self) -> &Vec<String> {
+        &self.sorted_names
+    }
+}
+
+impl<'de> Deserialize<'de> for ColumnFilter {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        Ok(Self::from(Vec::<String>::deserialize(deserializer)?))
+    }
+}

crates/core/src/schema/raw_table.rs

@@ -1,4 +1,4 @@
-use core::fmt::{self, Formatter, from_fn};
+use core::fmt::{self, Formatter, Write, from_fn};
 
 use alloc::{
     format,
@@ -10,7 +10,7 @@ use powersync_sqlite_nostd::{Connection, Destructor, ResultCode};
 
 use crate::{
     error::PowerSyncError,
-    schema::{RawTable, SchemaTable},
+    schema::{ColumnFilter, RawTable, SchemaTable},
     utils::{InsertIntoCrud, SqlBuffer, WriteType},
     views::table_columns_to_json_object,
 };
@@ -23,6 +23,7 @@ impl InferredTableStructure {
     pub fn read_from_database(
         table_name: &str,
         db: impl Connection,
+        ignored_local_columns: &ColumnFilter,
     ) -> Result<Option<Self>, PowerSyncError> {
         let stmt = db.prepare_v2("select name from pragma_table_info(?)")?;
         stmt.bind_text(1, table_name, Destructor::STATIC)?;
@@ -34,7 +35,7 @@ impl InferredTableStructure {
             let name = stmt.column_text(0)?;
             if name == "id" {
                 has_id_column = true;
-            } else {
+            } else if !ignored_local_columns.matches(name) {
                 columns.push(name.to_string());
             }
         }
@@ -63,7 +64,9 @@ pub fn generate_raw_table_trigger(
         return Err(PowerSyncError::argument_error("Table has no local name"));
     };
 
-    let Some(resolved_table) = InferredTableStructure::read_from_database(local_table_name, db)?
+    let local_only_columns = &table.schema.local_only_columns;
+    let Some(resolved_table) =
+        InferredTableStructure::read_from_database(local_table_name, db, local_only_columns)?
     else {
         return Err(PowerSyncError::argument_error(format!(
             "Could not find {} in local schema",
@@ -80,7 +83,27 @@ pub fn generate_raw_table_trigger(
     buffer.create_trigger("", trigger_name);
     buffer.trigger_after(write, local_table_name);
     // Skip the trigger for writes during sync_local, these aren't crud writes.
-    buffer.push_str("WHEN NOT powersync_in_sync_operation() BEGIN\n");
+    buffer.push_str("WHEN NOT powersync_in_sync_operation()");
+
+    if write == WriteType::Update && !local_only_columns.as_ref().is_empty() {
+        buffer.push_str(" AND\n(");
+        // If we have local-only columns, we want to add additional WHEN clauses to ensure the
+        // trigger runs for updates on synced columns.
+        for (i, name) in as_schema_table.column_names().enumerate() {
+            if i != 0 {
+                buffer.push_str(" OR ");
+            }
+
+            // Generate OLD."column" IS NOT NEW."column"
+            buffer.push_str("OLD.");
+            let _ = buffer.identifier().write_str(name);
+            buffer.push_str(" IS NOT NEW.");
+            let _ = buffer.identifier().write_str(name);
+        }
+        buffer.push_str(")");
+    }
+
+    buffer.push_str(" BEGIN\n");
 
     if table.schema.options.flags.insert_only() {
         if write != WriteType::Insert {

crates/core/src/schema/table_info.rs

@@ -37,6 +37,8 @@ pub struct RawTableSchema {
     /// Currently, this is only used to generate `CREATE TRIGGER` statements for the raw table.
     #[serde(default)]
     pub table_name: Option<String>,
+    #[serde(default)]
+    pub local_only_columns: ColumnFilter,
     #[serde(flatten)]
     pub options: CommonTableOptions,
 }

dart/test/schema_test.dart

@@ -280,6 +280,29 @@ END''',
           delete: '''
 CREATE TRIGGER "test_delete" AFTER DELETE ON "users" FOR EACH ROW WHEN NOT powersync_in_sync_operation() BEGIN
 INSERT INTO powersync_crud(op,id,type,old_values) VALUES ('DELETE', OLD.id, 'sync_type', json_object('email', powersync_strip_subtype(OLD."email"), 'email_verified', powersync_strip_subtype(OLD."email_verified")));
+END''',
+        ),
+        // Local-only columns, should not be included in ps_crud.
+        _RawTableTestCase(
+          createTable:
+              'CREATE TABLE users (id TEXT, synced_a TEXT, synced_b TEXT, local_a TEXT, local_b TEXT);',
+          tableOptions: {
+            'table_name': 'users',
+            'local_only_columns': ['local_a', 'local_b'],
+          },
+          insert: '''
+CREATE TRIGGER "test_insert" AFTER INSERT ON "users" FOR EACH ROW WHEN NOT powersync_in_sync_operation() BEGIN
+INSERT INTO powersync_crud(op,id,type,data) VALUES ('PUT', NEW.id, 'sync_type', json(powersync_diff('{}', json_object('synced_a', powersync_strip_subtype(NEW."synced_a"), 'synced_b', powersync_strip_subtype(NEW."synced_b")))));
+END''',
+          update: '''
+CREATE TRIGGER "test_update" AFTER UPDATE ON "users" FOR EACH ROW WHEN NOT powersync_in_sync_operation() AND
+(OLD."synced_a" IS NOT NEW."synced_a" OR OLD."synced_b" IS NOT NEW."synced_b") BEGIN
+SELECT CASE WHEN (OLD.id != NEW.id) THEN RAISE (FAIL, 'Cannot update id') END;
+INSERT INTO powersync_crud(op,id,type,data,options) VALUES ('PATCH', NEW.id, 'sync_type', json(powersync_diff(json_object('synced_a', powersync_strip_subtype(OLD."synced_a"), 'synced_b', powersync_strip_subtype(OLD."synced_b")), json_object('synced_a', powersync_strip_subtype(NEW."synced_a"), 'synced_b', powersync_strip_subtype(NEW."synced_b")))), 0);
+END''',
+          delete: '''
+CREATE TRIGGER "test_delete" AFTER DELETE ON "users" FOR EACH ROW WHEN NOT powersync_in_sync_operation() BEGIN
+INSERT INTO powersync_crud(op,id,type) VALUES ('DELETE', OLD.id, 'sync_type');
 END''',
         ),
       ];
@@ -330,9 +353,9 @@ SELECT
         db.select("SELECT name, sql FROM sqlite_schema WHERE type = 'trigger'");
 
     // Uncomment to help update expectations
-    // for (final row in foundTriggers) {
+    //for (final row in foundTriggers) {
     //  print(row['sql']);
-    // }
+    //}
 
     expect(foundTriggers, [
       {'name': 'test_insert', 'sql': insert},