set P.I and PN.I to less than pattern length if too long

CHANGELOG.md

@@ -22,6 +22,7 @@
 - **FIX**: divide by zero errors now explicitly return a 0 (e.g. `DIV 5 0` now returns 0 instead of -1), previously the behaviour was undefined and would crash the simulator
 - **FIX**: numerous crashing bugs with text entry
 - **FIX**: `i2c` bus crashes under high `M` times with external triggers
+- **FIX**: `P.I` and `PN.I` no longer set values longer than allowed
 
 ## v1.4.1
 - **NEW**: added Ansible remote commands `LV.CV` and `CY.CV`

src/ops/patterns.c

@@ -295,10 +295,10 @@ static void p_i_set(scene_state_t *ss, int16_t pn, int16_t i) {
     pn = normalise_pn(pn);
     i = normalise_idx(ss, pn, i);
     int16_t len = ss_get_pattern_len(ss, pn);
-    if (i < 0)
+    if (i < 0 || len == 0)
         ss_set_pattern_idx(ss, pn, 0);
-    else if (i > len)
-        ss_set_pattern_idx(ss, pn, len);
+    else if (i >= len)
+        ss_set_pattern_idx(ss, pn, len - 1);
     else
         ss_set_pattern_idx(ss, pn, i);
 }