Improve error messages when comparing swisstable iterators.

We check for comparisons of swisstable iterators from different heap allocations, which can indicate either iterators from different containers or that there was a rehash between when the iterators were initialized.

PiperOrigin-RevId: 487304602
Change-Id: I5c596c5ea07948d66e048f99937f9032a630344f

1 files changed, 21 insertions, 5 deletions

diff --git a/absl/container/internal/raw_hash_set_test.cc b/absl/container/internal/raw_hash_set_test.cc
index 6478d3fc..daa32814 100644
--- a/absl/container/internal/raw_hash_set_test.cc
+++ b/absl/container/internal/raw_hash_set_test.cc
@@ -2082,13 +2082,29 @@ TEST(TableDeathTest, IteratorInvalidAssertsEqualityOperator) {
   ASSERT_NE(iter2, t.end());
   t.erase(iter1);
   // Extra simple "regexp" as regexp support is highly varied across platforms.
-  const char* const kDeathMessage =
-      "Invalid operation on iterator. The element might have .*been erased or "
+  const char* const kErasedDeathMessage =
+      "Invalid iterator comparison. The element might have .*been erased or "
       "the table might have rehashed.";
-  EXPECT_DEATH_IF_SUPPORTED(void(iter1 == iter2), kDeathMessage);
-  EXPECT_DEATH_IF_SUPPORTED(void(iter2 != iter1), kDeathMessage);
+  EXPECT_DEATH_IF_SUPPORTED(void(iter1 == iter2), kErasedDeathMessage);
+  EXPECT_DEATH_IF_SUPPORTED(void(iter2 != iter1), kErasedDeathMessage);
   t.erase(iter2);
-  EXPECT_DEATH_IF_SUPPORTED(void(iter1 == iter2), kDeathMessage);
+  EXPECT_DEATH_IF_SUPPORTED(void(iter1 == iter2), kErasedDeathMessage);
+
+  IntTable t1, t2;
+  t1.insert(0);
+  t2.insert(0);
+  iter1 = t1.begin();
+  iter2 = t2.begin();
+  const char* const kContainerDiffDeathMessage =
+      "Invalid iterator comparison. The iterators may be from different "
+      ".*containers or the container might have rehashed.";
+  EXPECT_DEATH_IF_SUPPORTED(void(iter1 == iter2), kContainerDiffDeathMessage);
+  EXPECT_DEATH_IF_SUPPORTED(void(iter2 == iter1), kContainerDiffDeathMessage);
+
+  for (int i = 0; i < 10; ++i) t1.insert(i);
+  // There should have been a rehash in t1.
+  EXPECT_DEATH_IF_SUPPORTED(void(iter1 == t1.begin()),
+                            kContainerDiffDeathMessage);
 }
 
 #if defined(ABSL_INTERNAL_HASHTABLEZ_SAMPLE)