From f4c9039af1ec8aa936d7b374a2d827779257c724 Mon Sep 17 00:00:00 2001
From: Humza Shahid <humzasaur@gmail.com>
Date: Mon, 4 Aug 2025 08:33:48 +0100
Subject: [PATCH] fix failing unit test in
 search-list.sml/build-search-list.sml: perform bounds checking into array

---
 fcore/build-search-list.sml |  2 +-
 fcore/search-list.sml       | 11 +++++++----
 test/regression.sml         | 17 ++++++++++++++---
 3 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/fcore/build-search-list.sml b/fcore/build-search-list.sml
index 63d5332..6bf30ce 100644
--- a/fcore/build-search-list.sml
+++ b/fcore/build-search-list.sml
@@ -27,7 +27,7 @@ struct
     case rightStrings of
       hd :: tl =>
         let
-          val strIdx = absIdx - bufferIdx
+          val strIdx = Int.max (0, absIdx - bufferIdx)
         in
           if strIdx < String.size hd then
             helpNextMatch (strIdx, hd, tl, absIdx, searchString, 0)
diff --git a/fcore/search-list.sml b/fcore/search-list.sml
index 8111ccb..85b5312 100644
--- a/fcore/search-list.sml
+++ b/fcore/search-list.sml
@@ -226,11 +226,14 @@ struct
   fun goToNum (num, {left, right}: t) =
     case right of
       hd :: tl =>
-        if num >= Vector.sub (hd, 0) then
-          (* num is greater or equal to first el on right so go right *)
-          helpGoToNumRight (num, left, right)
+        if Vector.length hd > 0 then
+          if Vector.sub (hd, 0) >= Vector.sub (hd, 0) then
+            (* num is greater or equal to first el on right so go right *)
+            helpGoToNumRight (num, left, right)
+          else
+            (* num is less than first el on right so go left *)
+            helpGoToNumLeft (num, left, right)
         else
-          (* num is less than first el on right so go left *)
           helpGoToNumLeft (num, left, right)
     | [] => helpGoToNumLeft (num, left, right)
 
diff --git a/test/regression.sml b/test/regression.sml
index e6f9412..11e85cd 100644
--- a/test/regression.sml
+++ b/test/regression.sml
@@ -10,12 +10,12 @@ struct
       let
         val chr = String.sub (str, pos)
         val app = AppUpdate.update (app, InputMsg.CHAR_EVENT chr)
+                  handle _ => raise Fail (Int.toString pos)
       in
         updateLoop (pos + 1, str, app)
       end
 
-  fun updateAppWithChars (historyString, app) =
-    updateLoop (0, historyString, app)
+  fun applyChars (historyString, app) = updateLoop (0, historyString, app)
 
   fun appFromText text =
     let val buffer = LineGap.fromString text
@@ -36,8 +36,19 @@ struct
       str
     end
 
+  val initialApp = appFromText initialText
+
   val charEventTests = describe "CHAR_EVENT regressions"
-    [test "placeholder" (fn _ => Expect.isTrue true)]
+    [test "SearchList.goToNum vector bounds regression (1)" (fn _ =>
+       let
+         val app = appFromText initialText
+         val history = "G12dk"
+         val history = "100G55dkz33dk"
+         val newApp = applyChars (history, app)
+       in
+         (* just expect that we do not fail or throw an exception *)
+         Expect.isTrue true
+       end)]
 
   val tests = [charEventTests]
 end