From 13b1a72a3a71a565763be8af312bf3090182cc77 Mon Sep 17 00:00:00 2001
From: Jeff Bezanson <jeff.bezanson@gmail.com>
Date: Thu, 21 Dec 2017 23:18:32 -0500
Subject: [PATCH] prevent modifying vector after in-place conversion to string

part of #24388
---
 src/array.c           | 5 +++++
 test/strings/basic.jl | 8 ++++++++
 2 files changed, 13 insertions(+)

diff --git a/src/array.c b/src/array.c
index 6135704f8e7dd..f42b8cc36f517 100644
--- a/src/array.c
+++ b/src/array.c
@@ -441,6 +441,11 @@ JL_DLLEXPORT jl_value_t *jl_array_to_string(jl_array_t *a)
         if (jl_is_string(o)) {
             a->flags.isshared = 1;
             *(size_t*)o = jl_array_len(a);
+            a->nrows = 0;
+#ifdef STORE_ARRAY_LEN
+            a->length = 0;
+#endif
+            a->maxsize = 0;
             return o;
         }
     }
diff --git a/test/strings/basic.jl b/test/strings/basic.jl
index 385d8986d046d..831474bee1f46 100644
--- a/test/strings/basic.jl
+++ b/test/strings/basic.jl
@@ -794,3 +794,11 @@ end
 @test nextind("\xf8\x9f\x98\x84", 1) == 2
 @test next("\xf8\x9f\x98\x84z", 1)[2] == 2
 @test nextind("\xf8\x9f\x98\x84z", 1) == 2
+
+# issue #24388
+let v = unsafe_wrap(Vector{UInt8}, "abc")
+    s = String(v)
+    @test_throws BoundsError v[1]
+    push!(v, UInt8('x'))
+    @test s == "abc"
+end