From 408a15ba4e76879a512ebaf80d93d44145a7a27f Mon Sep 17 00:00:00 2001
From: Alon Zakai <azakai@google.com>
Date: Mon, 29 Aug 2022 08:23:48 -0700
Subject: Fix SmallVector's resize() method (#4979)

A resize from a large amount to a small amount would sometimes not clear
the flexible storage, if we used it before but not after.
---
 test/example/small_vector.cpp | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

(limited to 'test')

diff --git a/test/example/small_vector.cpp b/test/example/small_vector.cpp
index 29d964997..a1e394e23 100644
--- a/test/example/small_vector.cpp
+++ b/test/example/small_vector.cpp
@@ -66,12 +66,47 @@ template<typename T> void test(size_t N) {
     t.reserve(t.capacity() + 100);
     assert(t.capacity() >= N + 100);
   }
+  {
+    // Test resizing.
+    T t;
+
+    assert(t.empty());
+    t.resize(1);
+    assert(t.size() == 1);
+    t.resize(2);
+    assert(t.size() == 2);
+    t.resize(3);
+    assert(t.size() == 3);
+    t.resize(6);
+    assert(t.size() == 6);
+
+    // Now go in reverse.
+    t.resize(6);
+    assert(t.size() == 6);
+    t.resize(3);
+    assert(t.size() == 3);
+    t.resize(2);
+    assert(t.size() == 2);
+    t.resize(1);
+    assert(t.size() == 1);
+
+    // Test a big leap from nothing (rather than gradual increase as before).
+    t.clear();
+    assert(t.empty());
+    t.resize(6);
+    assert(t.size() == 6);
+    t.resize(2);
+    assert(t.size() == 2);
+    t.clear();
+    assert(t.empty());
+  }
 }
 
 int main() {
   test<SmallVector<int, 0>>(0);
   test<SmallVector<int, 1>>(1);
   test<SmallVector<int, 2>>(2);
+  test<SmallVector<int, 3>>(3);
   test<SmallVector<int, 10>>(10);
   std::cout << "ok.\n";
 }
-- 
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