From 3a2312e0bd3b1a57bd5ab8c3d57700fbba7ce16b Mon Sep 17 00:00:00 2001
From: David Selassie <dsel@fastmail.com>
Date: Thu, 6 Jul 2023 17:23:28 -0700
Subject: [PATCH] Interpret generate_series arguments as possibly NULL

---
 src/vtab/series.rs | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/src/vtab/series.rs b/src/vtab/series.rs
index 53d13b9..1e178de 100644
--- a/src/vtab/series.rs
+++ b/src/vtab/series.rs
@@ -8,7 +8,6 @@ use std::marker::PhantomData;
 use std::os::raw::c_int;
 
 use crate::ffi;
-use crate::types::Type;
 use crate::vtab::{
     eponymous_only_module, Context, IndexConstraintOp, IndexInfo, VTab, VTabConfig, VTabConnection,
     VTabCursor, Values,
@@ -198,21 +197,34 @@ impl SeriesTabCursor<'_> {
 unsafe impl VTabCursor for SeriesTabCursor<'_> {
     fn filter(&mut self, idx_num: c_int, _idx_str: Option<&str>, args: &Values<'_>) -> Result<()> {
         let mut idx_num = QueryPlanFlags::from_bits_truncate(idx_num);
+        let mut any_null = false;
         let mut i = 0;
         if idx_num.contains(QueryPlanFlags::START) {
-            self.min_value = args.get(i)?;
+            if let Some(min_value) = args.get(i)? {
+                self.min_value = min_value;
+            } else {
+                any_null = true;
+            }
             i += 1;
         } else {
             self.min_value = 0;
         }
         if idx_num.contains(QueryPlanFlags::STOP) {
-            self.max_value = args.get(i)?;
+            if let Some(max_value) = args.get(i)? {
+                self.max_value = max_value;
+            } else {
+                any_null = true;
+            }
             i += 1;
         } else {
             self.max_value = 0xffff_ffff;
         }
         if idx_num.contains(QueryPlanFlags::STEP) {
-            self.step = args.get(i)?;
+            if let Some(step) = args.get(i)? {
+                self.step = step;
+            } else {
+                any_null = true;
+            }
             if self.step == 0 {
                 self.step = 1;
             } else if self.step < 0 {
@@ -224,13 +236,11 @@ unsafe impl VTabCursor for SeriesTabCursor<'_> {
         } else {
             self.step = 1;
         };
-        for arg in args.iter() {
-            if arg.data_type() == Type::Null {
-                // If any of the constraints have a NULL value, then return no rows.
-                self.min_value = 1;
-                self.max_value = 0;
-                break;
-            }
+        if any_null {
+            // If any of the constraints have a NULL value, then
+            // return no rows.
+            self.min_value = 1;
+            self.max_value = 0;
         }
         self.is_desc = idx_num.contains(QueryPlanFlags::DESC);
         if self.is_desc {