Fix TS composite btree range scans

Author: JasonAtClockwork

crates/bindings-typescript/src/server/runtime.ts

@@ -896,6 +896,15 @@ export function makeTableView(
       } as PointIndex<any, any>;
     } else {
       // numColumns != 1
+      const isCompleteScalarKey = (range: any[]): boolean => {
+        // Preserve the point-scan path only for complete scalar keys.
+        // A complete key with a Range in the final position is still a range
+        // scan over that column with equality over the preceding prefix.
+        return (
+          range.length === numColumns && !(range[range.length - 1] instanceof Range)
+        );
+      };
+
       const serializeRange = (
         buffer: ResizableBuffer,
         range: any[]
@@ -920,12 +929,12 @@ export function makeTableView(
           writeBound(term.from);
           const rstartLen = writer.offset - rstartOffset;
           writeBound(term.to);
-          const rendLen = writer.offset - rstartLen;
+          const rendLen = writer.offset - rstartOffset - rstartLen;
           return [rstartOffset, prefix_elems, rstartLen, rendLen];
         } else {
           writer.writeU8(0);
           serializeTerm(writer, term);
-          const rstartLen = writer.offset;
+          const rstartLen = writer.offset - rstartOffset;
           const rendLen = 0;
           return [rstartOffset, prefix_elems, rstartLen, rendLen];
         }
@@ -936,7 +945,7 @@ export function makeTableView(
           // one-column prefix scan; normalize it to a single-element array so
           // `.length` and `serializeRange` see a prefix rather than NaN.
           if (!Array.isArray(range)) range = [range];
-          if (range.length === numColumns) {
+          if (isCompleteScalarKey(range)) {
             const buf = LEAF_BUF;
             const point_len = serializePoint(buf, range);
             const iter_id = sys.datastore_index_scan_point_bsatn(
@@ -958,7 +967,7 @@ export function makeTableView(
         },
         delete: (range: any[]): u32 => {
           if (!Array.isArray(range)) range = [range];
-          if (range.length === numColumns) {
+          if (isCompleteScalarKey(range)) {
             const buf = LEAF_BUF;
             const point_len = serializePoint(buf, range);
             return sys.datastore_delete_by_index_scan_point_bsatn(

crates/bindings-typescript/tests/index_prefix_filter.test.ts

@@ -56,6 +56,32 @@ function tallyView() {
   return view.by_board_def;
 }
 
+function tallyCountView() {
+  const ctx = new ModuleContext();
+  const tally = table(
+    {
+      name: 'tally',
+      indexes: [
+        {
+          accessor: 'by_board_count',
+          algorithm: 'btree',
+          columns: ['boardId', 'count'] as const,
+        },
+      ] as const,
+    },
+    {
+      id: t.u64().primaryKey().autoInc(),
+      boardId: t.u64(),
+      defId: t.string(),
+      count: t.u64(),
+    }
+  );
+
+  const rawTableDef = tally.tableDef(ctx, 'tally');
+  const view = makeTableView(ctx.typespace, rawTableDef) as any;
+  return view.by_board_count;
+}
+
 describe('multi-column index one-column prefix scan', () => {
   it('full two-column key works (point scan)', () => {
     const index = tallyView();
@@ -81,9 +107,31 @@ describe('multi-column index one-column prefix scan', () => {
     expect([...index.filter(range)]).toEqual([]);
   });
 
+  it('full key with Range in final column works (range scan)', () => {
+    const index = tallyCountView();
+    const range = new Range<bigint>(
+      { tag: 'included', value: 10n },
+      { tag: 'included', value: 20n }
+    );
+
+    expect(() => [...index.filter([1n, range])]).not.toThrow();
+    expect([...index.filter([1n, range])]).toEqual([]);
+  });
+
   it('delete() accepts a bare-scalar one-column prefix', () => {
     const index = tallyView();
     expect(() => index.delete(1n)).not.toThrow();
     expect(index.delete(1n)).toBe(0);
   });
+
+  it('delete() accepts a full key with Range in final column', () => {
+    const index = tallyCountView();
+    const range = new Range<bigint>(
+      { tag: 'included', value: 10n },
+      { tag: 'included', value: 20n }
+    );
+
+    expect(() => index.delete([1n, range])).not.toThrow();
+    expect(index.delete([1n, range])).toBe(0);
+  });
 });