add sqlite debug cli for nix. Fix cursor delete panic. Add tracing for cell indices in btree

core/storage/btree.rs

@@ -756,8 +756,11 @@ impl BTreeCursor {
             let mem_page = mem_page_rc.get();
 
             let contents = mem_page.contents.as_ref().unwrap();
+            let cell_count = contents.cell_count();
 
-            if cell_idx == contents.cell_count() {
+            tracing::trace!(cell_idx, cell_count, "get_next_record");
+
+            if cell_count == 0 || cell_idx == cell_count {
                 // do rightmost
                 let has_parent = self.stack.has_parent();
                 match contents.rightmost_pointer() {
@@ -3590,7 +3593,9 @@ impl BTreeCursor {
                 DeleteState::FindCell => {
                     let page = self.stack.top();
                     let mut cell_idx = self.stack.current_cell_index() as usize;
-                    cell_idx -= 1;
+                    if cell_idx > 0 {
+                        cell_idx -= 1;
+                    }
 
                     let contents = page.get().contents.as_ref().unwrap();
                     if cell_idx >= contents.cell_count() {
@@ -4439,6 +4444,11 @@ impl PageStack {
     /// Cell index of the current page
     fn current_cell_index(&self) -> i32 {
         let current = self.current();
+        tracing::event!(
+            tracing::Level::TRACE,
+            "current: cell_indices={:?}",
+            self.cell_indices
+        );
         self.cell_indices.borrow()[current]
     }
 
@@ -4453,14 +4463,32 @@ impl PageStack {
     /// We usually advance after going traversing a new page
     fn advance(&self) {
         let current = self.current();
-        tracing::trace!("pagestack::advance {}", self.cell_indices.borrow()[current],);
+        tracing::trace!(
+            "pagestack::advance {}, cell_indices={:?}",
+            self.cell_indices.borrow()[current],
+            self.cell_indices
+        );
         self.cell_indices.borrow_mut()[current] += 1;
+        tracing::event!(
+            tracing::Level::TRACE,
+            "after: cell_indices={:?}",
+            self.cell_indices
+        );
     }
 
     fn retreat(&self) {
         let current = self.current();
-        tracing::trace!("pagestack::retreat {}", self.cell_indices.borrow()[current]);
+        tracing::trace!(
+            "pagestack::retreat {}, cell_indices={:?}",
+            self.cell_indices.borrow()[current],
+            self.cell_indices
+        );
         self.cell_indices.borrow_mut()[current] -= 1;
+        tracing::event!(
+            tracing::Level::TRACE,
+            "after: cell_indices={:?}",
+            self.cell_indices
+        );
     }
 
     /// Move the cursor to the next cell in the current page according to the iteration direction.
@@ -4477,7 +4505,18 @@ impl PageStack {
 
     fn set_cell_index(&self, idx: i32) {
         let current = self.current();
-        self.cell_indices.borrow_mut()[current] = idx
+        tracing::event!(
+            tracing::Level::TRACE,
+            "set_cell_index={} cell_indices={:?}",
+            idx,
+            self.cell_indices
+        );
+        self.cell_indices.borrow_mut()[current] = idx;
+        tracing::event!(
+            tracing::Level::TRACE,
+            "after: cell_indices={:?}",
+            self.cell_indices
+        );
     }
 
     fn has_parent(&self) -> bool {

flake.nix

@@ -24,10 +24,17 @@
 
         lib = pkgs.lib;
 
+        # Custom SQLite package with debug enabled
+        sqlite-debug = pkgs.sqlite.overrideAttrs (oldAttrs: rec {
+          name = "sqlite-debug-${oldAttrs.version}";
+          configureFlags = oldAttrs.configureFlags ++ [ "--enable-debug" ];
+          dontStrip = true;
+          separateDebugInfo = true;
+        });
+
         cargoArtifacts = craneLib.buildDepsOnly {
           src = ./.;
           pname = "limbo";
-          stritcDeps = true;
           nativeBuildInputs = with pkgs; [ python3 ];
         };
 
@@ -58,7 +65,7 @@
         devShells.default = with pkgs; mkShell {
           nativeBuildInputs = [
             clang
-            sqlite
+            sqlite-debug  # Use debug-enabled SQLite
             gnumake
             tcl
             python3
@@ -77,4 +84,4 @@
         };
       }
     );
-}
+}