feat: add high-level checking for append-only tables

crates/deltalake-core/src/operations/delete.rs

@@ -275,6 +275,8 @@ impl std::future::IntoFuture for DeleteBuilder {
         let mut this = self;
 
         Box::pin(async move {
+            PROTOCOL.check_append_only(&this.snapshot)?;
+
             PROTOCOL.can_write_to(&this.snapshot)?;
 
             let state = this.state.unwrap_or_else(|| {

crates/deltalake-core/src/operations/transaction/protocol.rs

@@ -68,6 +68,14 @@ impl ProtocolChecker {
         2
     }
 
+    /// Check append-only at the high level (operation level)
+    pub fn check_append_only(&self, snapshot: &DeltaTableState) -> Result<(), TransactionError> {
+        if snapshot.table_config().append_only() {
+            return Err(TransactionError::DeltaTableAppendOnly);
+        }
+        Ok(())
+    }
+
     /// Check if delta-rs can read form the given delta table.
     pub fn can_read_from(&self, snapshot: &DeltaTableState) -> Result<(), TransactionError> {
         let required_features: Option<&HashSet<ReaderFeatures>> =

crates/deltalake-core/src/operations/update.rs

@@ -428,6 +428,8 @@ impl std::future::IntoFuture for UpdateBuilder {
         let mut this = self;
 
         Box::pin(async move {
+            PROTOCOL.check_append_only(&this.snapshot)?;
+
             PROTOCOL.can_write_to(&this.snapshot)?;
 
             let state = this.state.unwrap_or_else(|| {

crates/deltalake-core/src/operations/write.rs

@@ -371,6 +371,10 @@ impl std::future::IntoFuture for WriteBuilder {
         let mut this = self;
 
         Box::pin(async move {
+            if this.mode == SaveMode::Overwrite {
+                PROTOCOL.check_append_only(&this.snapshot)?;
+            }
+
             // Create table actions to initialize table in case it does not yet exist and should be created
             let mut actions = this.check_preconditions().await?;
 

crates/deltalake-core/src/protocol/mod.rs

@@ -578,7 +578,7 @@ impl DeltaOperation {
 }
 
 /// The SaveMode used when performing a DeltaOperation
-#[derive(Serialize, Deserialize, Debug, Clone)]
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
 pub enum SaveMode {
     /// Files will be appended to the target location.
     Append,