From 21bf859c0b6c37872214debda0b72c92962bafdd Mon Sep 17 00:00:00 2001
From: Gatefixer <313497061+lancedb-gatefixer[bot]@users.noreply.github.com>
Date: Thu, 6 Aug 2026 06:30:38 +0000
Subject: [PATCH] fix(python): validate compaction option bounds

---
 python/python/tests/test_table.py | 22 +++++++++++++
 python/src/table.rs               | 54 ++++++++++++++++++++++++++++---
 2 files changed, 71 insertions(+), 5 deletions(-)

diff --git a/python/python/tests/test_table.py b/python/python/tests/test_table.py
index 5fb5ce9c9..d764b9165 100644
--- a/python/python/tests/test_table.py
+++ b/python/python/tests/test_table.py
@@ -3404,6 +3404,28 @@ async def test_optimize_compaction_options(mem_db_async: AsyncConnection):
         await table.optimize(compaction_options={"unknown": 1})
 
 
+@pytest.mark.parametrize(
+    ("option", "value", "message"),
+    [
+        ("target_rows_per_fragment", 0, "must be between 1 and 4294967295"),
+        ("max_rows_per_group", 0, "must be between 1 and 4294967295"),
+        ("batch_size", 0, "must be between 1 and 4294967295"),
+        ("num_threads", 0, "must be greater than 0"),
+        ("target_rows_per_fragment", 2**32, "must be between 1 and 4294967295"),
+        ("max_rows_per_group", 2**32, "must be between 1 and 4294967295"),
+        ("batch_size", 2**32, "must be between 1 and 4294967295"),
+        ("io_buffer_size", 2**63, "must be at most 9223372036854775807"),
+    ],
+)
+@pytest.mark.asyncio
+async def test_optimize_compaction_options_validation(
+    mem_db_async: AsyncConnection, option: str, value: int, message: str
+):
+    table = await mem_db_async.create_table("test", data=[{"x": 1}])
+    with pytest.raises(ValueError, match=message):
+        await table.optimize(compaction_options={option: value})
+
+
 @pytest.mark.asyncio
 async def test_optimize_delete_unverified(tmp_db_async: AsyncConnection, tmp_path):
     table = await tmp_db_async.create_table(
diff --git a/python/src/table.rs b/python/src/table.rs
index 963183dea..a3555bdb6 100644
--- a/python/src/table.rs
+++ b/python/src/table.rs
@@ -40,6 +40,48 @@ enum PredicateArg {
     Sql(String),
 }
 
+fn validate_positive_u32(value: u64, name: &str) -> PyResult<usize> {
+    if !(1..=u32::MAX as u64).contains(&value) {
+        return Err(PyValueError::new_err(format!(
+            "{name} must be between 1 and {}",
+            u32::MAX
+        )));
+    }
+    Ok(value as usize)
+}
+
+fn positive_u32(value: &Bound<'_, PyAny>, name: &str) -> PyResult<usize> {
+    validate_positive_u32(value.extract()?, name)
+}
+
+fn optional_positive_u32(value: &Bound<'_, PyAny>, name: &str) -> PyResult<Option<usize>> {
+    value
+        .extract::<Option<u64>>()?
+        .map(|value| validate_positive_u32(value, name))
+        .transpose()
+}
+
+fn optional_positive_usize(value: &Bound<'_, PyAny>, name: &str) -> PyResult<Option<usize>> {
+    let value: Option<usize> = value.extract()?;
+    if value == Some(0) {
+        return Err(PyValueError::new_err(format!(
+            "{name} must be greater than 0"
+        )));
+    }
+    Ok(value)
+}
+
+fn optional_i64_bounded_u64(value: &Bound<'_, PyAny>, name: &str) -> PyResult<Option<u64>> {
+    let value: Option<u64> = value.extract()?;
+    if value.is_some_and(|value| value > i64::MAX as u64) {
+        return Err(PyValueError::new_err(format!(
+            "{name} must be at most {}",
+            i64::MAX
+        )));
+    }
+    Ok(value)
+}
+
 fn parse_compaction_options(options: Option<&Bound<'_, PyDict>>) -> PyResult<CompactionOptions> {
     let mut parsed = CompactionOptions::default();
     let Some(options) = options else {
@@ -49,16 +91,18 @@ fn parse_compaction_options(options: Option<&Bound<'_, PyDict>>) -> PyResult<Com
     for (key, value) in options.iter() {
         let key: String = key.extract()?;
         match key.as_str() {
-            "target_rows_per_fragment" => parsed.target_rows_per_fragment = value.extract()?,
-            "max_rows_per_group" => parsed.max_rows_per_group = value.extract()?,
+            "target_rows_per_fragment" => {
+                parsed.target_rows_per_fragment = positive_u32(&value, &key)?
+            }
+            "max_rows_per_group" => parsed.max_rows_per_group = positive_u32(&value, &key)?,
             "max_bytes_per_file" => parsed.max_bytes_per_file = value.extract()?,
             "materialize_deletions" => parsed.materialize_deletions = value.extract()?,
             "materialize_deletions_threshold" => {
                 parsed.materialize_deletions_threshold = value.extract()?
             }
-            "num_threads" => parsed.num_threads = value.extract()?,
-            "batch_size" => parsed.batch_size = value.extract()?,
-            "io_buffer_size" => parsed.io_buffer_size = value.extract()?,
+            "num_threads" => parsed.num_threads = optional_positive_usize(&value, &key)?,
+            "batch_size" => parsed.batch_size = optional_positive_u32(&value, &key)?,
+            "io_buffer_size" => parsed.io_buffer_size = optional_i64_bounded_u64(&value, &key)?,
             "defer_index_remap" => parsed.defer_index_remap = value.extract()?,
             "index_remap_mode" => {
                 let mode: String = value.extract()?;