From f9d101e747af9d9611229acbcd38b4b40a9ff7b0 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Sun, 28 Jun 2020 20:59:01 -0700
Subject: [PATCH] m[vector] Recover vector from error in .reset()

---
 src/hb-vector.hh | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/hb-vector.hh b/src/hb-vector.hh
index 079b94a6b..13517a9c2 100644
--- a/src/hb-vector.hh
+++ b/src/hb-vector.hh
@@ -80,7 +80,12 @@ struct hb_vector_t
     fini ();
   }
 
-  void reset () { resize (0); }
+  void reset ()
+  {
+    if (unlikely (in_error ()))
+      allocated = length; // Big hack!
+    resize (0);
+  }
 
   hb_vector_t& operator = (const hb_vector_t &o)
   {
@@ -181,7 +186,7 @@ struct hb_vector_t
   /* Allocate for size but don't adjust length. */
   bool alloc (unsigned int size)
   {
-    if (unlikely (allocated < 0))
+    if (unlikely (in_error ()))
       return false;
 
     if (likely (size <= (unsigned) allocated))
@@ -195,7 +200,7 @@ struct hb_vector_t
 
     Type *new_array = nullptr;
     bool overflows =
-      (int) new_allocated < 0 ||
+      (int) in_error () ||
       (new_allocated < (unsigned) allocated) ||
       hb_unsigned_mul_overflows (new_allocated, sizeof (Type));
     if (likely (!overflows))