diff --git a/kitty/decorations.c b/kitty/decorations.c
index a16a91bb1..b815dfb21 100644
--- a/kitty/decorations.c
+++ b/kitty/decorations.c
@@ -598,6 +598,8 @@ render_box_char(char_type ch, uint8_t *buf, unsigned width, unsigned height, dou
 #define S(ch, func, ...) case ch: SS(func(c, __VA_ARGS__))
 
     switch(ch) {
+        default: log_error("Unknown box drawing character: U+%x rendered as blank", ch); break;
+
         C(L'─', hline, 1);
         C(L'━', hline, 3);
         C(L'│', vline, 1);
diff --git a/kitty/fonts.c b/kitty/fonts.c
index 30a0481db..04284fb28 100644
--- a/kitty/fonts.c
+++ b/kitty/fonts.c
@@ -1038,7 +1038,7 @@ render_box_cell(FontGroup *fg, RunFont rf, CPUCell *cpu_cell, GPUCell *gpu_cell,
     FontCellMetrics scaled_metrics = fg->fcm;
     unsigned width = fg->fcm.cell_width, height = fg->fcm.cell_height;
     if (scale != 1) apply_scale_to_font_group(fg, NULL);
-    RAII_PyObject(ret, NULL); uint8_t *alpha_mask = NULL;
+    uint8_t *alpha_mask = NULL;
     ensure_canvas_can_fit(fg, num_glyphs + 1, rf.scale);
     if (num_glyphs == 1) {
         render_box_char(ch, fg->canvas.alpha_mask, width, height, fg->logical_dpi_x, fg->logical_dpi_y);