From 4a24bf8744922263c957baca43f8616d47a39131 Mon Sep 17 00:00:00 2001
From: Jameson Nash <vtjnash@gmail.com>
Date: Sat, 4 Nov 2023 06:22:45 -0400
Subject: [PATCH] fix out-of-bounds bug in BufferedVector (#91)

* fix out-of-bounds bug in BufferedVector
---------

Co-authored-by: Drvi <tomas.drvostep@gmail.com>
---
 src/BufferedVectors.jl  | 4 ++--
 test/BufferedVectors.jl | 7 ++++++-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/BufferedVectors.jl b/src/BufferedVectors.jl
index 70456fe..b7cca56 100644
--- a/src/BufferedVectors.jl
+++ b/src/BufferedVectors.jl
@@ -55,9 +55,9 @@ function shiftleft!(x::BufferedVector, n)
         empty!(x)
         return nothing
     end
-    unsafe_copyto!(x.elements, 1, x.elements, 1 + n, len - n + 1)
+    unsafe_copyto!(x.elements, 1, x.elements, 1 + n, len - n)
     x.occupied -= n
     return nothing
 end
 
-end # module
\ No newline at end of file
+end # module
diff --git a/test/BufferedVectors.jl b/test/BufferedVectors.jl
index ffa2ae7..7a0c41b 100644
--- a/test/BufferedVectors.jl
+++ b/test/BufferedVectors.jl
@@ -59,6 +59,10 @@ using SentinelArrays: BufferedVectors
     unsafe_push!(bv, 42)
     @test bv == [1, 42]
 
+    # --check-bounds=auto not available prior to Julia 1.8, so we force the default
+    # bounds check behavior by removing the flag from the command line
+    julia_cmd_default_boundscheck = Base.julia_cmd()
+    filter!(x->!startswith(x, "--check-bounds="), julia_cmd_default_boundscheck.exec)
     code = """
     using SentinelArrays
     using Test
@@ -67,7 +71,7 @@ using SentinelArrays: BufferedVectors
     @noinline unsafe(bv, i) = @inbounds bv[i]
     @test unsafe(bv, 2) == bv.elements[2]
     """
-    cmd = `$(Base.julia_cmd()) --startup-file=no --project=. --check-bounds=auto -e $code`
+    cmd = `$(julia_cmd_default_boundscheck) --startup-file=no --project=. -e $code`
     @test success(pipeline(cmd; stdout=stdout, stderr=stderr))
 
     bv = BufferedVector{Int32}()
@@ -78,6 +82,7 @@ using SentinelArrays: BufferedVectors
     bv = BufferedVector{Int}([1,2,3], 3)
     shiftleft!(bv, 1)
     @test bv == [2,3]
+    @test bv.elements[3] == 3 # the last element is not overwritten
 
     bv = BufferedVector{Int}([1,2,3], 3)
     shiftleft!(bv, 2)