From dbe93edb12e5dc53777e1e4d55e086f806d4e3b7 Mon Sep 17 00:00:00 2001
From: Wyatt Alt <wyatt.alt@gmail.com>
Date: Sun, 16 Aug 2026 13:04:46 -0700
Subject: [PATCH] fix: refuse a remote table as a materialized view before any
 request

The connection-level entry points hold a local-only boundary, but
from_table does not, and that is the entry both bindings use to refresh.
A remote table therefore reached a describe request and came back as a
plain table rather than as unsupported, so the caller paid a round trip
for a misleading error.

Check the boundary before the schema read.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 rust/lancedb/src/materialized_view.rs |  7 +++++++
 rust/lancedb/src/remote/table.rs      | 14 ++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/rust/lancedb/src/materialized_view.rs b/rust/lancedb/src/materialized_view.rs
index 7231edf80..bf228f0f0 100644
--- a/rust/lancedb/src/materialized_view.rs
+++ b/rust/lancedb/src/materialized_view.rs
@@ -656,6 +656,13 @@ impl MaterializedView {
     /// [`Error::NotSupported`] for a view whose kind this version cannot
     /// refresh.
     pub async fn from_table(table: Table) -> Result<Self> {
+        // Same local-only boundary the connection-level entry points hold,
+        // applied before the schema read so a remote table costs no request.
+        if table.as_native().is_none() {
+            return Err(Error::NotSupported {
+                message: "materialized views are supported only on local databases".into(),
+            });
+        }
         let schema = table.schema().await?;
         match materialized_view_kind(schema.metadata())? {
             Some(MaterializedViewKind::Select(definition)) => Ok(Self { table, definition }),
diff --git a/rust/lancedb/src/remote/table.rs b/rust/lancedb/src/remote/table.rs
index a0a4cebc2..b46ea4fbb 100644
--- a/rust/lancedb/src/remote/table.rs
+++ b/rust/lancedb/src/remote/table.rs
@@ -10156,6 +10156,20 @@ mod tests {
         );
     }
 
+    #[tokio::test]
+    async fn test_materialized_view_refused_without_a_request() {
+        // Materialized views are local-only. The table-level entry the
+        // bindings use must refuse a remote table before reading its schema,
+        // so the panicking handler is the assertion.
+        let table = Table::new_with_handler("my_table", |request| -> http::Response<String> {
+            panic!("unexpected request: {}", request.url().path())
+        });
+        let err = crate::MaterializedView::from_table(table)
+            .await
+            .unwrap_err();
+        assert!(matches!(err, Error::NotSupported { .. }), "got {err:?}");
+    }
+
     #[tokio::test]
     async fn test_create_branch_empty_name_rejected_client_side() {
         use lance::dataset::refs::Ref;